In some respects, it's a testament to how much the world of electronics has changed over the past ~25 years. It used to be that 555 was this Swiss-army-knife IC that you had to learn about. Multiple people published entire books about it!
Today, it's essentially obsolete. You're quite unlikely to find it in any competently-done commercial designs. Every analog trick you can do with it can be done more cheaply, more reliably, with better power efficiency, and with fewer external components using a modern MCU.
It's not that analog is dead, but it's solving different problems now. Including how to keep ultra-high-speed digital signals usable within the footprint of a PCB - which wasn't that much of a consideration in the golden days of the 555.
Yep, came to this realization awhile ago, about the superiority of digital in many cases, when I had an amplifier project with a dizzying number of requirements and a very large dynamic range and (log) linearity needed. Ended up using a few ranges of ADC’s, doing the required mathematical transform on a MCU, then outputting the required voltage with a DAC. The previous gen was some fairly complex circuit designed by a smart analog guy and still wasn’t nearly as performant
I'd guess that a 555 is also tougher than a microcontroller. I'm putting together an HV supply and thought about using a microcontroller but opted for a 555-based oscillator. Either one won't survive HV but I think the 555 will handle stray charges better.
Modern mucus are surprisingly fault tolerant. Just saying. It’s not like the bad old days where if you sneezed at a cmos chip it would probably be fried. I’m not sure how that stacks up to a 555 though.
My mucus is about as fault tolerant as it ever has been. Sometimes it gets really thick if the weather is dry or I'm sick, but otherwise I haven't noticed any difference. I find that drinking water helps.
Its kind of interesting: the 555 is such _horrible_ timer. It can't do a 50% duty cycle without extra BOM parts, even more parts to make a real PWM out of it, and it has terrible temperature and voltage stability. But somehow it persists.
There's still plenty of analog control out there, it's just all hidden away as parts can integrate the sensor, controller and actuator, all in one magic IC. And it can definitely be lower power and cheaper, in volume. The main weakness is the NRE is higher than the typical MCU project so it's not really seen in low volume or hobby level stuff.
Even in jellybean analog, almost everything you can do with a 555 timer you can do with a quad comparator. And more. Over a bigger voltage range, too. It’s usually a design smell to see a 555 used for anything in a professional design, even from before the tiny mcu era.
"You're quite unlikely to find it in any competently-done commercial designs."
You'll find them in tons of commercial designs - your modern headlights (which I manufacture) and off-road lights use them in droves. Short-timed lighting like automatic UVC sterilization lighting and such also still relies heavily upon a 555 timer just to act as the on/off switch for the power driver pushing the LEDs.
Now I’m curious: what is the role of the 555 timer in a headlight?
I have a bit of a pet peeve about car lights (usually exterior lights that aren’t the headlights) that are visibly pulsed. They can be distracting. I think they should all be designed to operate either at silly frequencies that are genuinely undetectable by human eyes (30kHz?) or to genuinely operate at DC.
"what is the role of the 555 timer in a headlight?"
Newer headlights use the 555 timer as a quick comparator to turn off the headlight when the corresponding turn signal is activated, and control the turn signal simultaneously.
Huh, I always imagined that newer cars would have a single CAN link to an ECU [0] in back, and that ECU would control all the lights near it. 555 timers may be cheap and robust, but monster wiring harnesses are not so cheap.
[0] Why do cars have special names for microcontrollers?
They aren't needed when the lighting is LED. The wiring harnesses going to more modern headlights are quite thin.
"I always imagined that newer cars would have a single CAN link to an ECU [0] in back, and that ECU would control all the lights near it."
They do but some are moving away because of the total lack of security and ability to compromise the CAN bus through the headlights to steal vehicles - read https://www.autoblog.com/news/vehicle-headlight-can-bus-inje... for what's going on there. They're too cheap to actually spend the money on real hardening so they're moving back to pure hardware control in many cases.
> to turn off the headlight when the corresponding turn signal is activated
Wait what? Why is a headlight influenced by a turn signal??
I realize that American brake lights and turn signals are more intertwined than is reasonable, I've seen the Technology Connections Youtube video. Are you telling me something similar is going on with headlights?
We sell kits with plenty of 555 timers (including some listed here)
It’s a shame that Arduino has effectively truncated kids learning with a full MCU as the “building block” of their learning
I see it also bite them in the arse with wasteful solutions. Often a BJT or power fet is all they need (say for a basic relay trigger). But if they aren’t presented with a shiny arduino compatible module explicitly designed for what they want, they get nervous
About half the kids I see make the intellectual jump, half end up not coming back
I do wish kids were taught basic soldering, it would make the learning process a lot less worrisome
The 555 and LM741 are still supreme learning tools. They are even simple enough to breadboard out with BJTs and analogue components. I’ve only seen a few extremely hardcore guys bother to conceptualise under the hood that deeply
> It’s a shame that Arduino has effectively truncated kids learning with a full MCU as the “building block” of their learning
Why? I think the vast majority of hobbyists used the 555 as a "black-box" chip. They now have a more intuitive, cheaper, and more power-efficient way of doing the same thing.
Pre-Arduino, learning electronics wasn't more profound. It was just less accessible. Nowadays, you have the same number of determined and talented hobbyists who eventually master some of the more arcane topics. You also have more people who learn just enough to get their art project done, and it's easier than it used to be... but why is that a bad thing?
There's a temptation to demand that others do things the hard way just because we had to. But is it healthy? I don't lament the demise of the 555 any more than I lament that the youth no longer knows how to put shoes on a horse.
> Pre-Arduino, learning electronics wasn't more profound. It was just less accessible.
This absolutely matches my experience. I was very interested in electronics growing up in the 80s. I took everything apart (occasionally without breaking it), I had those spring terminal "200 in 1" kits, a crappy soldering iron, and tons of enthusiasm and energy to channel into it. But I very quickly hit a wall trying to understand analog circuits, and I gave up (and redirected my interest to computers).
Some of it could be the limited information I had access to, in a small town, pre-Internet. There was a lot of math, and this was when I was like 8-10 years old, so it was way over my head. But I tried several times over the following decades to get back into it, and I just couldn't find a way in that connected with me.
The point of all of this is that in 2012 I stumbled across an Arduino kit and everything changed. Now I could apply the digital logic and programming concepts I understood to make things that did stuff. I rediscovered my interest in electronics, and the part that's most relevant here is that because it was accessible and fun, it gave me an on ramp to start to explore the analog world a bit more. The concepts began to make sense and build on each other as I developed an intuition for how they worked, and now I feel reasonably comfortable with analog circuits.
So I don't see it so much as nobody is going to learn other things because they can just throw a MCU at it, I think it's a great way to get started and then go on to develop a more thorough understanding of electronics (if that's your thing).
I started experimenting with electronics long pre-arduino as well. I studied electronics later. But still somehow I never got my brain quite wrapped around analog electronics, beyond the basics and the things following pure logic. I would still break my brain on a bi-stable multivibrator using analog components. I guess I am missing some gen.
That said, some analog principles are still needed in the back of your mind when making digital stuff. Input impedance, rise time, ripple etc.
... Are you me? I followed essentially the exact same path.
I got into electronics (and to some degree, computers) as a means to do something cool. I don't have the drive to memorize data sheets spend hours playing component golf. I just want my circuit to work, even if it's not the most efficient way possible to do it.
You raise an interesting issue to which I offer just ONE counterpoint. That is, a 555 circuit often requires external circuits that involve useful theory beyond basic circuits.
I’m thinking RC timing and voltage dividers. These have practical application. Would it ever get used elsewhere? That is where my thinking merges to yours.
Forty years from when I started that journey, not sure it can’t be learned from a wiki.
A potentiometer is a simple voltage divider, and I think often used as an input to the ADC of an MCU, as a means of turning some some value up or down.
> There's a temptation to demand that others do things the hard way just because we had to. But is it healthy? I don't lament the demise of the 555 any more than I lament that the youth no longer knows how to put shoes on a horse.
I agree with both you and the GP. Arduinos tend to make goofing around with electronics more accessible to more people. At the same time a lot of projects could be built very simply with just a couple timer chips. It's unfortunate people reach for a relatively complex solution (Arduino etc) to what's ultimately a simple problem. They would benefit a great deal from just knowing a blinking light can be made very simply with a simple circuit.
I liken it to people who reach for kubernets and docker and microservices and cloud infrastructure when a simple LAMP stack running on a single box will do. And people who reach for a hosted javascript app when a native one that doesn’t require internet will do. They’re not wrong, just unnecessarily complicating things because they learned how to do it the complicated way.
I get what you're saying and I don't disagree but I don't know if the analogy works.
An Arduino is very approachable in that you can just plug it into a USB port and tell it to blink a light following a very simple tutorial. No breadboards even, just plug in a device and open a program. Under the hood the Arduino is very complex but for the end user it's very simple.
A lot of Arduino compatible modules are also simple for the end user despite being very complex under the hood.
The simplicity for the end user is I think the biggest attraction for the Arduino. In your K8s analogy, it is not simple for the end user. Someone may build some K8s monstrosity because that's what a tutorial or bootcamp taught but it's very obviously complex. The hosted JavaScript app is a better Arduino analogy, it's a complex solution under the hood but presents a relatively simple user experience.
Starting in electronics 47 years ago, digital electronics clicked for me in a way that analog didn’t. My early analog circuits often used digital components to create clear deterministic behavior. The 7400 was my do everything black box and the 555 was the timer of choice when it became available.
But I always dreamed of a digital future. When I was very young, microprocessors fascinated but intimidated me with their need for special support chips, and I would design 4 bit computers I couldn’t afford to build using 7400 logic and 4 bit SRAM.
For a while, I strayed from the path and learned to program on my C2-8P computer that my brother and I bought. By middle school, I was more or less distracted, and came back to technology later with the TS1000 and later the c64. Eventually, the AT2323 brought me back into electronics with MCUs, and I found it was the world I always fantasised about as a 7 year old kid designing 4 bit ALUs. I don’t know why I missed out on the early PIC days, but I think it was girls, cars, and LSD, mostly lol.
Anyway, since then, I’ll unashamedly put a 6 pin mcu in just to flash a light, but I’ll make it flash in a better way, so that it grabs your attention when it is starting or stopping flashing, for example. Or it will flash in a way that communicates just a little more about what it’s telling you. I find with MCUs your stuff can be just a little bit better in a thousand subtle ways, and despite 10000x the parts count, more reliable and resistant to environmental factors. With modern mixed-signal MCUs that can drive 60ma on a GPIO, most things can boil down to a single chip with a few external parts.
Then you get to stuff like the esp32 platform, where for $1 you get a single chip solution that puts my first 486 PC to shame playing DOOM, even while bit-banging the video output. There’s no point in using something less capable unless you are making more than a thousand units, in which case you can still end up with a $0.10 risc-V running a respectable 24 mhz at 32 bits, with more flash and ram than my old C2-8P.
The esp32 is amazing. It has a flexible IP block that can create complex patterns on gpio without the cpu needing to bit bang. You can use one core for the ip stack and the other for example for running micropython scripts. Its the 555 of today, a million times.
I grew up with Arduinos, never used 555 because it draws too much current for what it is doing. I get how it once was a popular thing, but if I need a simple delay circuit or simple logic that needs to e precise I do it discretev if ir needs to be more complex there is any number of MCUs.
I was 100% self thought and teach electronics in art university now. And I have to say I can't really confirm your suspicions about "the kids", sure many stay at the module level (totally okay, they study arts not electronics), but many don't. I had a student who over the course of 2 years built a brain wave reading circuit with a specialized instrumentation amplifier IC, to filter out grid EMF she built an opamp based notch filter and that woman had nearly no help from me and no prior education in the field. That analog stuff isn't going away anytime soon.
It is a bit unfair though as one is comparing new MCU to ancient parts. For example the TLV9301 is a updated version on the 741 and is superior in basically every possible spec, but people still use the 741 out of habit. And if you need a lower power discrete timer, the 555 is not the best way to do it in 2024. There are a huge number of options.
For art projects I totally get using a MCU. You're probably only making one and the product is the art. The engineering just gets in the way so minimizing man hours, which includes the time to learn to do the thing, is critical. It will be tough to beat a MCU on that metric.
That is what I meant: the 555 is a habitual option by people who grew up with it. The arduino can be an habitual option by people who grew up with that.
Not every project is mass produced or must be highly optimized when it comes to size, cost or power consumption. People use what they know, and what they know depends on when they grew into it.
Arduino is very much less about the board itself, and more of a software framework. Every single "Arduino compatible" board beyond the standard Uno or Micro have a bunch of macros essentially just telling the compiler what the standard Arduino pin definitions go where. That even extends to boards like the 2560, since I know the port registers and the silk screening on that board are completely different.
The problem with starting with a 555 timer is that the things you can make with a 555 timer aren’t impressive to kids anymore. Oh, you made a sound that gets higher pitched when there’s more light on it? I thought that shit was amazing when I was 8. But my son wouldn’t look twice at that. So we started with Arduino so that the first thing he created was something he saw as “cool.”
I wonder if that will come around though, where it's cool because it seems so simple or 'real' compared to black box software or AI walking talking robot or wherever we are.
I grew up interested in stuff like that, taking walkie-talkies apart and building electromagnets with nails etc. - despite the availability of the world wide web & DAB radio.
I disagree. I as an adult with zero prior experience with electronics have recently completed the book "Make: Electronics", which contains such experiments, and I got a sense of amazement very much resembling one that a(n) (intellectually curious) child would have. A 555, a couple of trimpots and a speaker can be loads of fun!
I’m in a 3 year mechatronics program, and we covered 555, LM741, and similar ICs in our 2nd semester PLC/digital/electronics class. No microcontrollers until year 2. I don’t feel I conceptualized it very well, but it gave me a good whetted appetite to dive further.
This tension between two paths, the microcontroller path vs the analog path, there is a bit of an analog to this in the game Factorio. You can use combinators to build sophisticated circuits (the microcontroller path), but there's also a lot you can do with just a few red wires (the analog path).
Why Arduinos in particular? We're in an era where you can choose any MCU (ARM, Espressif, RiscV e tc), pick a language you like within limits (C, C++, Rust, Python (sort of)), and make it happen. Open KiCad, design a PCB, and have it arrive from Shenzhen in 10 days. Or, order a dev board, and attach additional circuits to it. (STM32 Discovery, nordic dev kit, one of the cheap Chinese ones "pill" etc.) Design whatever circuits you want. Use passives, or string together ICs.
555 is obsolete tech. I see this as equivalent to suggesting someone buy an Apple II instead of a modern PC.
This is a good question. I think that "Arduino" means a couple of different things, and it's sometimes hard to guess what someone means from context.
There's "Arduino" the old 16-bit MCU board, and there's "Arduino" the development platform supporting a huge ecosystem of MCUs, libraries, and accessories.
For instance, I use the Arduino IDE, but with a variety of dev boards to suit my needs. For my work, I don't need to cost-engineer anything, so I'm satisfied with pre-made modules that I plug into my own application boards.
A lot of engineers dismissed Arduino long ago, and are utterly unaware that the broader ecosystem even exists.
I don't object to a beginner choosing the original Arduino board, for which there's huge amounts of tutorials and documentation. And then, maybe graduating to a more performant board if they take an interest in more advanced or specialized projects.
I always use the term “arduino” when I describe any of the MCU “space” to somebody not in the field. Odds are much better that a person heard of “those arduino thinks you can use to program your lights” than “esp32s3” even though the s3 is my goto microcontroller.
The second the conversation steers towards actual product selection… that is the time to introduce the MCU space and steer them to the right fit. You do always have to remember that most of those arduino MCU’s have a 5 volt logic level that is more compatible with “LEGO part style electronics” than things like the ESP chips.
> It’s a shame that Arduino has effectively truncated kids learning with a full MCU as the “building block” of their learning
There is a reason I didn’t truly get into electronics as a kid. Only in adulthood with the introduction of the arduino (really esp8266) did any of that stuff click enough to get my interest.
All that analog stuff just got in the way from what I actually wanted to do. Build cool stuff. But back then there was way too much “complexity” between me and whatever cool thing I wanted to build and none of it was the good kind of complexity.
Starting out with modern MCU’s take all that away and let me build at the level of the project where what I do actually impacts things. If I had to worry about all that analog stuff, I never would have bother, just like as a kid I never bothered—I just did all my cool shit on the computer instead!
Plenty of people are commenting on how modern microcontrollers are better than the 555. I agree, with a caveat: the 555 is a great learning tool. It is complex enough to be interesting, yet simple enough to be well understood. It is easy to clip an oscilloscope to it's pins to have a visual representation of how its inputs affects its outputs. It is a stepping stone that helps people learn how to build more complex circuits. Much as some software developers have to understand assembly language to build the most fundamental bits of software (e.g. compilers), some people have need to understand electronics to build the most fundamental bits of hardware.
Only problem is that an oscilloscope isn't accessible to beginners. It's a specialist piece of equipment that takes time to learn how to use, and are furiously expensive at best for someone who doesn't know they might like electronics to buy. That's fundamentally why people are lauding the benefits of microcontrollers, figuring out what's wrong with one doesn't require an O-scope.
That really depends upon the context. Many learn electronics in a classroom environment. Even for those who learn electronics independently, it has been possible to get new oscilloscopes that work at audio frequencies for well under $100 for many years. It looks like scopes that operate upto 20 MHz have been available for under $100 for a couple of years. They aren't great, but they are still powerful tools for learning.
And while scopes do take time to learn, learning about scopes themselves will convey a lot of fundamental information about electronics. I also wouldn't underestimate the difficulty in learning how to use microcontrollers. While using something like Arduino (boards, shields, development tools, and libraries) may be straight forward, the learning curve rises steeply as soon as you try to do anything truly independently. More steeply, I would suggest, than learning how to use an osilloscope. Besides, most of those development boards cost a lot more than a bare chip.
Indeed. An intuitive, easy to use oscilloscope needs at least to be digital and hence expensive. An alternative is using an electronics workbench simulator, but then again you might as well go fully digital.
When circuits become larger than trivial, the analog way is noise and temperature sensitive, you will spend a lot of time on tweaking those aspects by themselves.
I always found DACs/IO to be the limiting thing with microcontrollers. That and latency in general. When you were doing analog stuff with op-amps, yeah, you were setting yourself up for other problems like thermal drift, but there was never any worry that you were going to run out of capacity like you would switching tasks on a microcontroller, and latency was negligible. Plus there weren't many wires and you could see it on a scope. It was all satisfyingly immediate. I wonder what kind of cheap and ubiquitous DSPs(?) people use for that kind of niche nowadays, to do it digitally(?). Do they string DACs together on a bus somehow? How do you get, say, signals flowing around at a couple hundred kHz sample rates, with nice dataflow parallelism -- and then get those signals out to actuators, without much latency -- in that world? Like, what would you use to mix a bunch of audio and run some IIR filters with 20ns latency? Or control, say, four motors with, I dunno, 1 kHz bandwidth? I get this feeling that DACs remain a bottleneck and you're rapidly looking at expensive stuff to do that with a microcontroller, but maybe I'm wrong; I don't do this stuff.
As an FPGA developer: much agreed. We know exactly what's happening every clock cycle (or at least can), and often are able to have extremely deterministic computation. You can do this on micros, but anything with good performance will have some caching, maybe context switching, etc. The polarfire SoC marketing has a graph showing either determinism or performance (I can dig it up if interested). In FPGA land, we define the pipelining such that we get both. I usually go out to an RFIC then stop caring, but you can calculate the latencies the as well.
Apropos. I made TV-surveillance unit when 555 was almost brand new. Maybe 1977. The start of a picture was long negative pulse, easy to recognize with 555, which triggered second 555, which triggered third 555 in unison with the horizontal scan pulse. Thus you had fairly accurate point selected in the screen, showing a dot, while camera info was sampled and compared to a preset value. Thus the watchmen could use few knobs and select a point in the screen, which would raise an alarm when illumination changed. Because it was so cheap, you could select multiple triggering points. No fancy microprocessors this time, which were too slow anyways.
I'm probably being unpopular writing this, but I never quite liked the 555. Not diminishing its value and the ingenuity that went into its design; I rather found myself much more attracted by CMOS gates, also in analog circuits. One day I was playing with PLLs and to better understand how phase detectors work, I built a proof of concept motion detector off a single quad xor chip (4030 probably), 1st gate working as ultrasound oscillator connected to a tx capsule, 2nd one biased as linear amplifier with input connected to a rx capsule, 3rd gate working as phase detector taking both 1 and 2 gates outputs, 4th gate driving a LED, which would flash every time I moved the hand in front of the capsules as I was delaying one of the two signals, which triggered the gate.
Very fun and instructional. The interesting part is that a CMOS digital gate can become a decent linear amplifier if properly biased, not unlike more common opamps, so where high linearity or fidelity in audio signals aren't a must, it can be quite an interesting part.
As an example, here's a equalizer built around a 4049 quad inverter gate chip.
As for digital gates, I couldn't recommend more the TTL and CMOS cookbooks by Don Lancaster: they're a goldmine of ideas. 2nd one is available for free at author's site.
He’s working on a new book that attempts to disprove evolution or at least show cases to the contrary, advocating for a grand design as a primary mechanism instead. Curious to read it, I’m hopeful he will release it.
Your comment appears grey to me so I assume someone downvoted you? How strange.
At any rate, I do own his books on electronics as a kind of an amusing look into the history of how electronics were taught, but I do find it to be a positive thing in the world to have curious individuals like himself.
People from all walks of life believe all sorts of kooky shit. That’s the spice of it I suppose.
My biggest critiques are that it consistently fails its predictions. You’d see an endless stream of intermediate forms going in so many directions. Instead, we saw few if any, nature organized more hierarchically, and organisms just appear out of thin air after extinctions (eg Cambrian Explosion). Instead of falsification, scientists keep making excuses for it like it is a religion that can’t be wrong.
I’ll add that humans have observed creatures, in their areas and in captivity, for a long time. We haven’t seen the chickens start giving birth to different animals. I’m grateful the fire ants and poisonous spiders we’re dodging haven’t turned into something more effective. Dumb evolution would have a crazy number of adaptation streams happening, many attempts per species, to create all the life we see. Instead, we see exactly zero movement from one kind of animal to another with changes only happening within kinds.
Whereas, studies of creation itself have proven the opposite. Everything from our non-life experiments to evolutionary algorithms show a creator who fine tunes is necessary. The universe itself has many constants that never change, they work together in precise ways, all has perfect reliability, and life on Earth depends on most of them. Complexity of most of biology is such that we’re incapable of manufacturing it. (See a lung vs a respirator.) It only gets more and more impossible over time the more we learned.
On time scales (X is millions of years old), they seem to assume the Earth didn’t change much at all over a long period of time. A specific thing changes at rate X. They’ll roll the clock back that much until they hit a point in their theory. Both human literature (esp Genesis) and the fossil record show catastrophes with huge effects on the Earth. It probably went through many changes. So, all time estimates that make that assumption are faith-based, likely-incorrect beliefs no matter how many textbooks they end up in. There is a minority studying Catastrophism or something like that to understand their effect.
Finally, godless science that broke from Christian scientists, like Newton and Pascal, all backed David Hume saying only material, observable things exist. Nothing else is ever allowed in scientific theory. A faith-based, unproven belief. While still making godless and materialism axiomatic, the same scientists tell us of a world outside our universe, exceeding the laws of physics, and maybe even having effects on observed phenomenon. Instead of things with evidence (eg Bible), they’ve shifted to purely-imaginary constructs outside the universe to support their claims which themselves contradict the Hume foundation they demand of us. They do it while denying the logical implications of the complexity and fine-tuning we’ve observed.
Those are some examples of counters to mainstream creation, like evolution and long timescales, being a pile of faith-based dogma that continues to fail in scientific experiments, historical writings, complexity theory, and global observations by laypeople. Outside of minor adaptation, evolution theory is provably false which leaves God as the primary hypothesis. From there, we consider whichever God claim has the most evidence and impact. That’s Jesus Christ. :)
Built many a 555 timer circuit back in the day! But in modern times, I can get an ATMega328p already attached to a PC board for $2.50 and load code on it to do whatever I want, including blink a red LED.
Can you actually get a genuine Atmel for that price? Bottom-rung Chinese Arduino clones sure, but you better order 10 of them because they will randomly stop working as you're tinkering with your circuit.
Not only are cheap microcontrollers often an easier choice for things the NE555 might be used for, they often draw far less power as well. I personally prefer to use an even smaller and cheaper micro like the ATTiny13A. It's also worth noting that your traditional 555 timers don't like to run below 5V, for that you'll need something like an LMC555. If you're building up a parts inventory, it often makes sense to have a bunch of very cheap micros rather than special purpose parts.
Except, it's not an advantage in any practical sense. Programmers cost pennies, toolchains are free and easy to use, and there are ample examples for simple tasks such as "toggle a pin in a particular way". The overall learning curve is almost certainly less steep than the learning curve for all the modes and quirks of the 555.
What matters in production is that a 555-based circuit will use more power, that it's four components to source and install instead of one, and so on. Don't get me wrong, I like the 555, just like I like vacuum tubes, but it's nearly as dead.
"that it's four components to source and install instead of one,"
The ATMega needs about ten components to get properly operational for programming vs a simple 555 timer circuit. Oh, and then you also need the programmer and toolchain for making the code.
Or you can just use some basic math and thrown down native hardware to do the job. One of the biggest off-road lighting manufacturers on the planet does exactly this with 555 timers.
I manufacture lighting controls of various sorts as my current profession.
Another way of looking at it is the 555 is useless without multiple extra parts, where as most MCUs can operate with only a bypass cap (and even that is often optional in practice). But you do have to buy a programmer ($5 these days) and get comfortable with firmware, which puts some analog folks off. I'll admit that there is a certain elegance and appeal to using only parts you fully understand and nothing extraneous.
Even if you have a microcontroller, there are simple situations where the 555 can come in handy.
For example, switch debouncer could be solved in code, resistor+capacitor or other methods. But you know what's one of the best performing switch debouncers?
1-bit of memory with an analog comparator. Aka: a 555 Timer.
> 555 is useless without multiple extra parts
Not needed for bistable multi vibrator (aka: just a flip flop mode). Which happens to be the debouncer circuit.
I'm curious what the circumstances are where that would be worth the extra BOM count if you're already feeding the input into a microcontroller. Needing to detect extremely short pulses where you can't spare a pin interrupt? Something else I can't think of?
You can add the 555 Timer to an already completed design if it is later discovered that debouncing was an unsolved problem.
I don't think it is always appropriate to assume that code can be rewritten (or rearchitected) to fit your needs. Sometimes its easier to solve problems with a touch of extra external hardware.
I recently used a 555 (and some other simple parts) to fix some timing issue my ham radio's internal CW keyer seemed to be having. Maybe I could have used an ESP32 module that I also had lying around, but I could run the 555 directly off of the ~12 volt power supply, and it was also more fun to build the little circuit.
The NE555 helped me get my first tech job in high school after I gave a presentation at a Nodebots community meetup. (It also, in some way, helped me land a job at Texas Instruments while I was in university during the COVID pandemic.) It was also the focus of the first tutorial I made for Instructables a few years ago. I always remember it fondly.
Without the 555 how can we have such fun make contests? The original www.555contest.com by Chris Gammell and Jeri Ellsworth (2011) had a tremendous response. 11 years later Hackaday held one with very creative entries. If you enter a contest you'll be forced out of your comfort zone (programming with solder) and will appreciate MCU's even more when you're done!
If you're lucky you'll get a phone call from (the late) Hans Camenzind as I did in 2011. And maybe you'll invent something goofy, like "Le Dominoux": https://youtu.be/PQOjkuJtBfM?si=Np2MSKgAp4ULwzcl
I love the circuits on this site (1). Kind of quirky layout (pretty sure the parent page uses "frames") but has fifty 555 circuits as well as 100+ transistor circuits, etc on the site. Def a labor of love. (Buy the CD, ha ha.)
I find the pin description and internal schematic a bit lacking on this website. Pin 5 isn't shown internally connected to the voltage divider, and is simply described as "affecting the timing".
Here's my tip for the 555 timer: Learn what's inside it! As you can see on the "Inside the 555" page, there are fewer than 10 functional components inside and three of them are resistors.
For some reason I always struggled to remember the different operating mode configurations, what they are called, and how to set them up. But one day I was trying to build a specific thing and decided to sit down and actually understand the 555. To my surprise, it's really simple in operation and requires relatively little electronics theory to understand and derive the different configurations yourself. Once I did that, I haven't forgotten it and I can come up with more creative uses for the 555.
The Evil Mad Scientist kits are a great way to learn what's inside it. They are faithful replicas of the internal 555 circuitry, built with discrete transistors and resistors.
You mentioned only ten functional components inside it, but if you look at individual transistors and resistors, there are quite a few more.
'10' would be counting the comparator and 2 op-amps as 3 components, the replicas you're pointing at break those out to discretes too, because once you've started down that road, why wouldn't you?
With everything going 3.3V these days with no 5V tolerance (can't have nice things ofc), is there some kind of 333 timer that would do the same job but down to those logic levels?
In some respects, it's a testament to how much the world of electronics has changed over the past ~25 years. It used to be that 555 was this Swiss-army-knife IC that you had to learn about. Multiple people published entire books about it!
Today, it's essentially obsolete. You're quite unlikely to find it in any competently-done commercial designs. Every analog trick you can do with it can be done more cheaply, more reliably, with better power efficiency, and with fewer external components using a modern MCU.
It's not that analog is dead, but it's solving different problems now. Including how to keep ultra-high-speed digital signals usable within the footprint of a PCB - which wasn't that much of a consideration in the golden days of the 555.
Yep, came to this realization awhile ago, about the superiority of digital in many cases, when I had an amplifier project with a dizzying number of requirements and a very large dynamic range and (log) linearity needed. Ended up using a few ranges of ADC’s, doing the required mathematical transform on a MCU, then outputting the required voltage with a DAC. The previous gen was some fairly complex circuit designed by a smart analog guy and still wasn’t nearly as performant
There is still at least one niche for it: very simple circuits which requires >5v. Using 555 lets you skip the regulator and drivers.
But even there, it's high Iq limits its applicability.
I'd guess that a 555 is also tougher than a microcontroller. I'm putting together an HV supply and thought about using a microcontroller but opted for a 555-based oscillator. Either one won't survive HV but I think the 555 will handle stray charges better.
Modern mucus are surprisingly fault tolerant. Just saying. It’s not like the bad old days where if you sneezed at a cmos chip it would probably be fried. I’m not sure how that stacks up to a 555 though.
My mucus is about as fault tolerant as it ever has been. Sometimes it gets really thick if the weather is dry or I'm sick, but otherwise I haven't noticed any difference. I find that drinking water helps.
lol. Eventually, spellcheck will eliminate my need to type altogether.
Its kind of interesting: the 555 is such _horrible_ timer. It can't do a 50% duty cycle without extra BOM parts, even more parts to make a real PWM out of it, and it has terrible temperature and voltage stability. But somehow it persists.
I think it's more that the 555 is basically the heart of hysteretic controller in a box, but it doesn't have the other stuff you need.
https://en.wikipedia.org/wiki/Bang–bang_control
There's still plenty of analog control out there, it's just all hidden away as parts can integrate the sensor, controller and actuator, all in one magic IC. And it can definitely be lower power and cheaper, in volume. The main weakness is the NRE is higher than the typical MCU project so it's not really seen in low volume or hobby level stuff.
Even in jellybean analog, almost everything you can do with a 555 timer you can do with a quad comparator. And more. Over a bigger voltage range, too. It’s usually a design smell to see a 555 used for anything in a professional design, even from before the tiny mcu era.
It makes a nifty missing pulse detector, though.
"You're quite unlikely to find it in any competently-done commercial designs."
You'll find them in tons of commercial designs - your modern headlights (which I manufacture) and off-road lights use them in droves. Short-timed lighting like automatic UVC sterilization lighting and such also still relies heavily upon a 555 timer just to act as the on/off switch for the power driver pushing the LEDs.
Now I’m curious: what is the role of the 555 timer in a headlight?
I have a bit of a pet peeve about car lights (usually exterior lights that aren’t the headlights) that are visibly pulsed. They can be distracting. I think they should all be designed to operate either at silly frequencies that are genuinely undetectable by human eyes (30kHz?) or to genuinely operate at DC.
"what is the role of the 555 timer in a headlight?"
Newer headlights use the 555 timer as a quick comparator to turn off the headlight when the corresponding turn signal is activated, and control the turn signal simultaneously.
Is this for a western car maker?
Haven't seen 555 in a commercial product with modern design for a long long time.
Huh, I always imagined that newer cars would have a single CAN link to an ECU [0] in back, and that ECU would control all the lights near it. 555 timers may be cheap and robust, but monster wiring harnesses are not so cheap.
[0] Why do cars have special names for microcontrollers?
"but monster wiring harnesses are not so cheap."
They aren't needed when the lighting is LED. The wiring harnesses going to more modern headlights are quite thin.
"I always imagined that newer cars would have a single CAN link to an ECU [0] in back, and that ECU would control all the lights near it."
They do but some are moving away because of the total lack of security and ability to compromise the CAN bus through the headlights to steal vehicles - read https://www.autoblog.com/news/vehicle-headlight-can-bus-inje... for what's going on there. They're too cheap to actually spend the money on real hardening so they're moving back to pure hardware control in many cases.
> to turn off the headlight when the corresponding turn signal is activated
Wait what? Why is a headlight influenced by a turn signal??
I realize that American brake lights and turn signals are more intertwined than is reasonable, I've seen the Technology Connections Youtube video. Are you telling me something similar is going on with headlights?
> Wait what? Why is a headlight influenced by a turn signal??
Some new cars, mainly luxury ones, dim headlights. It is to avoid blinding other drivers who may be looking at your turn signal.
There's still room for synchro and servo theory I learned in the Navy but I really like the digital world a lot, so flexible.
Can you recommend books/courses that cover this new approach you’re talking about?
We sell kits with plenty of 555 timers (including some listed here)
It’s a shame that Arduino has effectively truncated kids learning with a full MCU as the “building block” of their learning
I see it also bite them in the arse with wasteful solutions. Often a BJT or power fet is all they need (say for a basic relay trigger). But if they aren’t presented with a shiny arduino compatible module explicitly designed for what they want, they get nervous
About half the kids I see make the intellectual jump, half end up not coming back
I do wish kids were taught basic soldering, it would make the learning process a lot less worrisome
The 555 and LM741 are still supreme learning tools. They are even simple enough to breadboard out with BJTs and analogue components. I’ve only seen a few extremely hardcore guys bother to conceptualise under the hood that deeply
> It’s a shame that Arduino has effectively truncated kids learning with a full MCU as the “building block” of their learning
Why? I think the vast majority of hobbyists used the 555 as a "black-box" chip. They now have a more intuitive, cheaper, and more power-efficient way of doing the same thing.
Pre-Arduino, learning electronics wasn't more profound. It was just less accessible. Nowadays, you have the same number of determined and talented hobbyists who eventually master some of the more arcane topics. You also have more people who learn just enough to get their art project done, and it's easier than it used to be... but why is that a bad thing?
There's a temptation to demand that others do things the hard way just because we had to. But is it healthy? I don't lament the demise of the 555 any more than I lament that the youth no longer knows how to put shoes on a horse.
> Pre-Arduino, learning electronics wasn't more profound. It was just less accessible.
This absolutely matches my experience. I was very interested in electronics growing up in the 80s. I took everything apart (occasionally without breaking it), I had those spring terminal "200 in 1" kits, a crappy soldering iron, and tons of enthusiasm and energy to channel into it. But I very quickly hit a wall trying to understand analog circuits, and I gave up (and redirected my interest to computers).
Some of it could be the limited information I had access to, in a small town, pre-Internet. There was a lot of math, and this was when I was like 8-10 years old, so it was way over my head. But I tried several times over the following decades to get back into it, and I just couldn't find a way in that connected with me.
The point of all of this is that in 2012 I stumbled across an Arduino kit and everything changed. Now I could apply the digital logic and programming concepts I understood to make things that did stuff. I rediscovered my interest in electronics, and the part that's most relevant here is that because it was accessible and fun, it gave me an on ramp to start to explore the analog world a bit more. The concepts began to make sense and build on each other as I developed an intuition for how they worked, and now I feel reasonably comfortable with analog circuits.
So I don't see it so much as nobody is going to learn other things because they can just throw a MCU at it, I think it's a great way to get started and then go on to develop a more thorough understanding of electronics (if that's your thing).
I started experimenting with electronics long pre-arduino as well. I studied electronics later. But still somehow I never got my brain quite wrapped around analog electronics, beyond the basics and the things following pure logic. I would still break my brain on a bi-stable multivibrator using analog components. I guess I am missing some gen.
That said, some analog principles are still needed in the back of your mind when making digital stuff. Input impedance, rise time, ripple etc.
... Are you me? I followed essentially the exact same path.
I got into electronics (and to some degree, computers) as a means to do something cool. I don't have the drive to memorize data sheets spend hours playing component golf. I just want my circuit to work, even if it's not the most efficient way possible to do it.
You raise an interesting issue to which I offer just ONE counterpoint. That is, a 555 circuit often requires external circuits that involve useful theory beyond basic circuits.
I’m thinking RC timing and voltage dividers. These have practical application. Would it ever get used elsewhere? That is where my thinking merges to yours.
Forty years from when I started that journey, not sure it can’t be learned from a wiki.
Voltage dividers are still commonly used in MCU-laden designs, as are RC timing circuits.
(The power supply sitting next to that MCU has a divider-based feedback loop, usually.)
These possibly can't be learned from a wiki, but they can absolutely be learned from the Art of Electronics for a low price.
A potentiometer is a simple voltage divider, and I think often used as an input to the ADC of an MCU, as a means of turning some some value up or down.
> There's a temptation to demand that others do things the hard way just because we had to. But is it healthy? I don't lament the demise of the 555 any more than I lament that the youth no longer knows how to put shoes on a horse.
I agree with both you and the GP. Arduinos tend to make goofing around with electronics more accessible to more people. At the same time a lot of projects could be built very simply with just a couple timer chips. It's unfortunate people reach for a relatively complex solution (Arduino etc) to what's ultimately a simple problem. They would benefit a great deal from just knowing a blinking light can be made very simply with a simple circuit.
I liken it to people who reach for kubernets and docker and microservices and cloud infrastructure when a simple LAMP stack running on a single box will do. And people who reach for a hosted javascript app when a native one that doesn’t require internet will do. They’re not wrong, just unnecessarily complicating things because they learned how to do it the complicated way.
I get what you're saying and I don't disagree but I don't know if the analogy works.
An Arduino is very approachable in that you can just plug it into a USB port and tell it to blink a light following a very simple tutorial. No breadboards even, just plug in a device and open a program. Under the hood the Arduino is very complex but for the end user it's very simple.
A lot of Arduino compatible modules are also simple for the end user despite being very complex under the hood.
The simplicity for the end user is I think the biggest attraction for the Arduino. In your K8s analogy, it is not simple for the end user. Someone may build some K8s monstrosity because that's what a tutorial or bootcamp taught but it's very obviously complex. The hosted JavaScript app is a better Arduino analogy, it's a complex solution under the hood but presents a relatively simple user experience.
Starting in electronics 47 years ago, digital electronics clicked for me in a way that analog didn’t. My early analog circuits often used digital components to create clear deterministic behavior. The 7400 was my do everything black box and the 555 was the timer of choice when it became available.
But I always dreamed of a digital future. When I was very young, microprocessors fascinated but intimidated me with their need for special support chips, and I would design 4 bit computers I couldn’t afford to build using 7400 logic and 4 bit SRAM.
For a while, I strayed from the path and learned to program on my C2-8P computer that my brother and I bought. By middle school, I was more or less distracted, and came back to technology later with the TS1000 and later the c64. Eventually, the AT2323 brought me back into electronics with MCUs, and I found it was the world I always fantasised about as a 7 year old kid designing 4 bit ALUs. I don’t know why I missed out on the early PIC days, but I think it was girls, cars, and LSD, mostly lol.
Anyway, since then, I’ll unashamedly put a 6 pin mcu in just to flash a light, but I’ll make it flash in a better way, so that it grabs your attention when it is starting or stopping flashing, for example. Or it will flash in a way that communicates just a little more about what it’s telling you. I find with MCUs your stuff can be just a little bit better in a thousand subtle ways, and despite 10000x the parts count, more reliable and resistant to environmental factors. With modern mixed-signal MCUs that can drive 60ma on a GPIO, most things can boil down to a single chip with a few external parts.
Then you get to stuff like the esp32 platform, where for $1 you get a single chip solution that puts my first 486 PC to shame playing DOOM, even while bit-banging the video output. There’s no point in using something less capable unless you are making more than a thousand units, in which case you can still end up with a $0.10 risc-V running a respectable 24 mhz at 32 bits, with more flash and ram than my old C2-8P.
The esp32 is amazing. It has a flexible IP block that can create complex patterns on gpio without the cpu needing to bit bang. You can use one core for the ip stack and the other for example for running micropython scripts. Its the 555 of today, a million times.
> By middle school, I was more or less distracted, and came back to technology later
Lol this also happened to me, I wonder how common this is?
I grew up with Arduinos, never used 555 because it draws too much current for what it is doing. I get how it once was a popular thing, but if I need a simple delay circuit or simple logic that needs to e precise I do it discretev if ir needs to be more complex there is any number of MCUs.
I was 100% self thought and teach electronics in art university now. And I have to say I can't really confirm your suspicions about "the kids", sure many stay at the module level (totally okay, they study arts not electronics), but many don't. I had a student who over the course of 2 years built a brain wave reading circuit with a specialized instrumentation amplifier IC, to filter out grid EMF she built an opamp based notch filter and that woman had nearly no help from me and no prior education in the field. That analog stuff isn't going away anytime soon.
It is a bit unfair though as one is comparing new MCU to ancient parts. For example the TLV9301 is a updated version on the 741 and is superior in basically every possible spec, but people still use the 741 out of habit. And if you need a lower power discrete timer, the 555 is not the best way to do it in 2024. There are a huge number of options.
For art projects I totally get using a MCU. You're probably only making one and the product is the art. The engineering just gets in the way so minimizing man hours, which includes the time to learn to do the thing, is critical. It will be tough to beat a MCU on that metric.
That is what I meant: the 555 is a habitual option by people who grew up with it. The arduino can be an habitual option by people who grew up with that.
Not every project is mass produced or must be highly optimized when it comes to size, cost or power consumption. People use what they know, and what they know depends on when they grew into it.
Arduino is very much less about the board itself, and more of a software framework. Every single "Arduino compatible" board beyond the standard Uno or Micro have a bunch of macros essentially just telling the compiler what the standard Arduino pin definitions go where. That even extends to boards like the 2560, since I know the port registers and the silk screening on that board are completely different.
The problem with starting with a 555 timer is that the things you can make with a 555 timer aren’t impressive to kids anymore. Oh, you made a sound that gets higher pitched when there’s more light on it? I thought that shit was amazing when I was 8. But my son wouldn’t look twice at that. So we started with Arduino so that the first thing he created was something he saw as “cool.”
I wonder if that will come around though, where it's cool because it seems so simple or 'real' compared to black box software or AI walking talking robot or wherever we are.
I grew up interested in stuff like that, taking walkie-talkies apart and building electromagnets with nails etc. - despite the availability of the world wide web & DAB radio.
One of the circuits on the site is a 20000 V zapper [1]. Would even that fail to interest today's kids?
[1] https://www.555-timer-circuits.com/stun-gun.html
I disagree. I as an adult with zero prior experience with electronics have recently completed the book "Make: Electronics", which contains such experiments, and I got a sense of amazement very much resembling one that a(n) (intellectually curious) child would have. A 555, a couple of trimpots and a speaker can be loads of fun!
I’m in a 3 year mechatronics program, and we covered 555, LM741, and similar ICs in our 2nd semester PLC/digital/electronics class. No microcontrollers until year 2. I don’t feel I conceptualized it very well, but it gave me a good whetted appetite to dive further.
This tension between two paths, the microcontroller path vs the analog path, there is a bit of an analog to this in the game Factorio. You can use combinators to build sophisticated circuits (the microcontroller path), but there's also a lot you can do with just a few red wires (the analog path).
Why Arduinos in particular? We're in an era where you can choose any MCU (ARM, Espressif, RiscV e tc), pick a language you like within limits (C, C++, Rust, Python (sort of)), and make it happen. Open KiCad, design a PCB, and have it arrive from Shenzhen in 10 days. Or, order a dev board, and attach additional circuits to it. (STM32 Discovery, nordic dev kit, one of the cheap Chinese ones "pill" etc.) Design whatever circuits you want. Use passives, or string together ICs.
555 is obsolete tech. I see this as equivalent to suggesting someone buy an Apple II instead of a modern PC.
>>> Why Arduinos in particular?
This is a good question. I think that "Arduino" means a couple of different things, and it's sometimes hard to guess what someone means from context.
There's "Arduino" the old 16-bit MCU board, and there's "Arduino" the development platform supporting a huge ecosystem of MCUs, libraries, and accessories.
For instance, I use the Arduino IDE, but with a variety of dev boards to suit my needs. For my work, I don't need to cost-engineer anything, so I'm satisfied with pre-made modules that I plug into my own application boards.
A lot of engineers dismissed Arduino long ago, and are utterly unaware that the broader ecosystem even exists.
I don't object to a beginner choosing the original Arduino board, for which there's huge amounts of tutorials and documentation. And then, maybe graduating to a more performant board if they take an interest in more advanced or specialized projects.
I always use the term “arduino” when I describe any of the MCU “space” to somebody not in the field. Odds are much better that a person heard of “those arduino thinks you can use to program your lights” than “esp32s3” even though the s3 is my goto microcontroller.
The second the conversation steers towards actual product selection… that is the time to introduce the MCU space and steer them to the right fit. You do always have to remember that most of those arduino MCU’s have a 5 volt logic level that is more compatible with “LEGO part style electronics” than things like the ESP chips.
Link to your kits?
Seconding this.
> It’s a shame that Arduino has effectively truncated kids learning with a full MCU as the “building block” of their learning
There is a reason I didn’t truly get into electronics as a kid. Only in adulthood with the introduction of the arduino (really esp8266) did any of that stuff click enough to get my interest.
All that analog stuff just got in the way from what I actually wanted to do. Build cool stuff. But back then there was way too much “complexity” between me and whatever cool thing I wanted to build and none of it was the good kind of complexity.
Starting out with modern MCU’s take all that away and let me build at the level of the project where what I do actually impacts things. If I had to worry about all that analog stuff, I never would have bother, just like as a kid I never bothered—I just did all my cool shit on the computer instead!
Plenty of people are commenting on how modern microcontrollers are better than the 555. I agree, with a caveat: the 555 is a great learning tool. It is complex enough to be interesting, yet simple enough to be well understood. It is easy to clip an oscilloscope to it's pins to have a visual representation of how its inputs affects its outputs. It is a stepping stone that helps people learn how to build more complex circuits. Much as some software developers have to understand assembly language to build the most fundamental bits of software (e.g. compilers), some people have need to understand electronics to build the most fundamental bits of hardware.
Only problem is that an oscilloscope isn't accessible to beginners. It's a specialist piece of equipment that takes time to learn how to use, and are furiously expensive at best for someone who doesn't know they might like electronics to buy. That's fundamentally why people are lauding the benefits of microcontrollers, figuring out what's wrong with one doesn't require an O-scope.
That really depends upon the context. Many learn electronics in a classroom environment. Even for those who learn electronics independently, it has been possible to get new oscilloscopes that work at audio frequencies for well under $100 for many years. It looks like scopes that operate upto 20 MHz have been available for under $100 for a couple of years. They aren't great, but they are still powerful tools for learning.
And while scopes do take time to learn, learning about scopes themselves will convey a lot of fundamental information about electronics. I also wouldn't underestimate the difficulty in learning how to use microcontrollers. While using something like Arduino (boards, shields, development tools, and libraries) may be straight forward, the learning curve rises steeply as soon as you try to do anything truly independently. More steeply, I would suggest, than learning how to use an osilloscope. Besides, most of those development boards cost a lot more than a bare chip.
Indeed. An intuitive, easy to use oscilloscope needs at least to be digital and hence expensive. An alternative is using an electronics workbench simulator, but then again you might as well go fully digital.
When circuits become larger than trivial, the analog way is noise and temperature sensitive, you will spend a lot of time on tweaking those aspects by themselves.
I always found DACs/IO to be the limiting thing with microcontrollers. That and latency in general. When you were doing analog stuff with op-amps, yeah, you were setting yourself up for other problems like thermal drift, but there was never any worry that you were going to run out of capacity like you would switching tasks on a microcontroller, and latency was negligible. Plus there weren't many wires and you could see it on a scope. It was all satisfyingly immediate. I wonder what kind of cheap and ubiquitous DSPs(?) people use for that kind of niche nowadays, to do it digitally(?). Do they string DACs together on a bus somehow? How do you get, say, signals flowing around at a couple hundred kHz sample rates, with nice dataflow parallelism -- and then get those signals out to actuators, without much latency -- in that world? Like, what would you use to mix a bunch of audio and run some IIR filters with 20ns latency? Or control, say, four motors with, I dunno, 1 kHz bandwidth? I get this feeling that DACs remain a bottleneck and you're rapidly looking at expensive stuff to do that with a microcontroller, but maybe I'm wrong; I don't do this stuff.
As an FPGA developer: much agreed. We know exactly what's happening every clock cycle (or at least can), and often are able to have extremely deterministic computation. You can do this on micros, but anything with good performance will have some caching, maybe context switching, etc. The polarfire SoC marketing has a graph showing either determinism or performance (I can dig it up if interested). In FPGA land, we define the pipelining such that we get both. I usually go out to an RFIC then stop caring, but you can calculate the latencies the as well.
Fpga's have the best of both worlds!
I'm not an expert by any definition of the term, but a book on programming for the Raspberry Pi Pico with Micropython recommends the MCP3008 ADC.
Apropos. I made TV-surveillance unit when 555 was almost brand new. Maybe 1977. The start of a picture was long negative pulse, easy to recognize with 555, which triggered second 555, which triggered third 555 in unison with the horizontal scan pulse. Thus you had fairly accurate point selected in the screen, showing a dot, while camera info was sampled and compared to a preset value. Thus the watchmen could use few knobs and select a point in the screen, which would raise an alarm when illumination changed. Because it was so cheap, you could select multiple triggering points. No fancy microprocessors this time, which were too slow anyways.
Thats awesome!
You could make it so you could control it with a light pen. It would integrate over a window of a single scan line?
A slightly more complex device could retrigger and sum into a bucket brigade and integrate over a region.
Whoa that's a really cool application! Another example of limitations begetting creativity.
I'm probably being unpopular writing this, but I never quite liked the 555. Not diminishing its value and the ingenuity that went into its design; I rather found myself much more attracted by CMOS gates, also in analog circuits. One day I was playing with PLLs and to better understand how phase detectors work, I built a proof of concept motion detector off a single quad xor chip (4030 probably), 1st gate working as ultrasound oscillator connected to a tx capsule, 2nd one biased as linear amplifier with input connected to a rx capsule, 3rd gate working as phase detector taking both 1 and 2 gates outputs, 4th gate driving a LED, which would flash every time I moved the hand in front of the capsules as I was delaying one of the two signals, which triggered the gate. Very fun and instructional. The interesting part is that a CMOS digital gate can become a decent linear amplifier if properly biased, not unlike more common opamps, so where high linearity or fidelity in audio signals aren't a must, it can be quite an interesting part.
As an example, here's a equalizer built around a 4049 quad inverter gate chip.
http://www.runoffgroove.com/mreq.html
As for digital gates, I couldn't recommend more the TTL and CMOS cookbooks by Don Lancaster: they're a goldmine of ideas. 2nd one is available for free at author's site.
https://www.tinaja.com/ebooks/cmoscb.pdf
The awesome Ben Eater gives the clearest explanation I've seen of how the 555 timer works internally: https://www.youtube.com/watch?v=kRlSFm519Bo
Shout out to Forest M Mims III, the OG 555 circuit guru.https://en.wikipedia.org/wiki/Forrest_Mims
He’s working on a new book that attempts to disprove evolution or at least show cases to the contrary, advocating for a grand design as a primary mechanism instead. Curious to read it, I’m hopeful he will release it.
Also a global warming denier. I’d love to see him explain how this is wrong?
https://climate.nasa.gov/vital-signs/global-temperature/?int...
Your comment appears grey to me so I assume someone downvoted you? How strange.
At any rate, I do own his books on electronics as a kind of an amusing look into the history of how electronics were taught, but I do find it to be a positive thing in the world to have curious individuals like himself.
People from all walks of life believe all sorts of kooky shit. That’s the spice of it I suppose.
You might enjoy this article which lists all the articles of faith evolutionists believe in:
https://answersingenesis.org/theory-of-evolution/12-the-basi...
My biggest critiques are that it consistently fails its predictions. You’d see an endless stream of intermediate forms going in so many directions. Instead, we saw few if any, nature organized more hierarchically, and organisms just appear out of thin air after extinctions (eg Cambrian Explosion). Instead of falsification, scientists keep making excuses for it like it is a religion that can’t be wrong.
I’ll add that humans have observed creatures, in their areas and in captivity, for a long time. We haven’t seen the chickens start giving birth to different animals. I’m grateful the fire ants and poisonous spiders we’re dodging haven’t turned into something more effective. Dumb evolution would have a crazy number of adaptation streams happening, many attempts per species, to create all the life we see. Instead, we see exactly zero movement from one kind of animal to another with changes only happening within kinds.
Whereas, studies of creation itself have proven the opposite. Everything from our non-life experiments to evolutionary algorithms show a creator who fine tunes is necessary. The universe itself has many constants that never change, they work together in precise ways, all has perfect reliability, and life on Earth depends on most of them. Complexity of most of biology is such that we’re incapable of manufacturing it. (See a lung vs a respirator.) It only gets more and more impossible over time the more we learned.
On time scales (X is millions of years old), they seem to assume the Earth didn’t change much at all over a long period of time. A specific thing changes at rate X. They’ll roll the clock back that much until they hit a point in their theory. Both human literature (esp Genesis) and the fossil record show catastrophes with huge effects on the Earth. It probably went through many changes. So, all time estimates that make that assumption are faith-based, likely-incorrect beliefs no matter how many textbooks they end up in. There is a minority studying Catastrophism or something like that to understand their effect.
Finally, godless science that broke from Christian scientists, like Newton and Pascal, all backed David Hume saying only material, observable things exist. Nothing else is ever allowed in scientific theory. A faith-based, unproven belief. While still making godless and materialism axiomatic, the same scientists tell us of a world outside our universe, exceeding the laws of physics, and maybe even having effects on observed phenomenon. Instead of things with evidence (eg Bible), they’ve shifted to purely-imaginary constructs outside the universe to support their claims which themselves contradict the Hume foundation they demand of us. They do it while denying the logical implications of the complexity and fine-tuning we’ve observed.
Those are some examples of counters to mainstream creation, like evolution and long timescales, being a pile of faith-based dogma that continues to fail in scientific experiments, historical writings, complexity theory, and global observations by laypeople. Outside of minor adaptation, evolution theory is provably false which leaves God as the primary hypothesis. From there, we consider whichever God claim has the most evidence and impact. That’s Jesus Christ. :)
Built many a 555 timer circuit back in the day! But in modern times, I can get an ATMega328p already attached to a PC board for $2.50 and load code on it to do whatever I want, including blink a red LED.
Can you actually get a genuine Atmel for that price? Bottom-rung Chinese Arduino clones sure, but you better order 10 of them because they will randomly stop working as you're tinkering with your circuit.
Hell, you can get an ESP32 with wifi and bluetooth for that price.
why would you buy an ATMega328p for that price if you can get an ESP32 with wifi/ble and awesome rust support? ;)
Not only are cheap microcontrollers often an easier choice for things the NE555 might be used for, they often draw far less power as well. I personally prefer to use an even smaller and cheaper micro like the ATTiny13A. It's also worth noting that your traditional 555 timers don't like to run below 5V, for that you'll need something like an LMC555. If you're building up a parts inventory, it often makes sense to have a bunch of very cheap micros rather than special purpose parts.
The main advantage of 555 timer is that it is configured with a resistor/capacitor kit. No computer or programming required.
Microcontrollers obviously have more than 1 bit of memory + 2x analog comparators + one 33% / 66% voltage divider (which is all a 555 timer truly is).
What is surprising however is how flexible 1 bit of memory + 2x analog comparators + one 33% / 66% voltage divider
Except, it's not an advantage in any practical sense. Programmers cost pennies, toolchains are free and easy to use, and there are ample examples for simple tasks such as "toggle a pin in a particular way". The overall learning curve is almost certainly less steep than the learning curve for all the modes and quirks of the 555.
What matters in production is that a 555-based circuit will use more power, that it's four components to source and install instead of one, and so on. Don't get me wrong, I like the 555, just like I like vacuum tubes, but it's nearly as dead.
"that it's four components to source and install instead of one,"
The ATMega needs about ten components to get properly operational for programming vs a simple 555 timer circuit. Oh, and then you also need the programmer and toolchain for making the code.
Or you can just use some basic math and thrown down native hardware to do the job. One of the biggest off-road lighting manufacturers on the planet does exactly this with 555 timers.
I manufacture lighting controls of various sorts as my current profession.
Another way of looking at it is the 555 is useless without multiple extra parts, where as most MCUs can operate with only a bypass cap (and even that is often optional in practice). But you do have to buy a programmer ($5 these days) and get comfortable with firmware, which puts some analog folks off. I'll admit that there is a certain elegance and appeal to using only parts you fully understand and nothing extraneous.
Even if you have a microcontroller, there are simple situations where the 555 can come in handy.
For example, switch debouncer could be solved in code, resistor+capacitor or other methods. But you know what's one of the best performing switch debouncers?
1-bit of memory with an analog comparator. Aka: a 555 Timer.
> 555 is useless without multiple extra parts
Not needed for bistable multi vibrator (aka: just a flip flop mode). Which happens to be the debouncer circuit.
I'm curious what the circumstances are where that would be worth the extra BOM count if you're already feeding the input into a microcontroller. Needing to detect extremely short pulses where you can't spare a pin interrupt? Something else I can't think of?
Black Box engineering.
You can add the 555 Timer to an already completed design if it is later discovered that debouncing was an unsolved problem.
I don't think it is always appropriate to assume that code can be rewritten (or rearchitected) to fit your needs. Sometimes its easier to solve problems with a touch of extra external hardware.
Could always use a 555 as a charge pump for your micro power mcu too.
Indeed, a small $0.23 mcu may have its own internal RC oscillator, or even a MEMS based resonator on a PLL. =3
I recently used a 555 (and some other simple parts) to fix some timing issue my ham radio's internal CW keyer seemed to be having. Maybe I could have used an ESP32 module that I also had lying around, but I could run the 555 directly off of the ~12 volt power supply, and it was also more fun to build the little circuit.
More details if curious: https://www.reddit.com/r/amateurradio/comments/1eo9ki7/xiegy...
The NE555 helped me get my first tech job in high school after I gave a presentation at a Nodebots community meetup. (It also, in some way, helped me land a job at Texas Instruments while I was in university during the COVID pandemic.) It was also the focus of the first tutorial I made for Instructables a few years ago. I always remember it fondly.
Without the 555 how can we have such fun make contests? The original www.555contest.com by Chris Gammell and Jeri Ellsworth (2011) had a tremendous response. 11 years later Hackaday held one with very creative entries. If you enter a contest you'll be forced out of your comfort zone (programming with solder) and will appreciate MCU's even more when you're done! If you're lucky you'll get a phone call from (the late) Hans Camenzind as I did in 2011. And maybe you'll invent something goofy, like "Le Dominoux": https://youtu.be/PQOjkuJtBfM?si=Np2MSKgAp4ULwzcl
Holy cow. Those things are still around?
I cut my teeth on them, about 40 years ago.
I love the circuits on this site (1). Kind of quirky layout (pretty sure the parent page uses "frames") but has fifty 555 circuits as well as 100+ transistor circuits, etc on the site. Def a labor of love. (Buy the CD, ha ha.)
1) https://www.talkingelectronics.com/projects/50%20-%20555%20C...
I find the pin description and internal schematic a bit lacking on this website. Pin 5 isn't shown internally connected to the voltage divider, and is simply described as "affecting the timing".
Clark Zapper… Hmm sure offers some interesting properties!
> This device is used tocure, treat and prevent any disease. It will cure anything.
https://www.555-timer-circuits.com/clark-zapper.html
The internal diagram appears to be incorrect, https://www.555-timer-circuits.com/inside-the-555.html
The internal resistors should be connected to the upper comparator. Also, that diagram just seems confusing. Something like this makes more sense: https://www.theengineeringknowledge.com/wp-content/uploads/2...
Might be interested to check out this legendary book: https://en.m.wikipedia.org/wiki/The_Art_of_Electronics
Here's my tip for the 555 timer: Learn what's inside it! As you can see on the "Inside the 555" page, there are fewer than 10 functional components inside and three of them are resistors.
For some reason I always struggled to remember the different operating mode configurations, what they are called, and how to set them up. But one day I was trying to build a specific thing and decided to sit down and actually understand the 555. To my surprise, it's really simple in operation and requires relatively little electronics theory to understand and derive the different configurations yourself. Once I did that, I haven't forgotten it and I can come up with more creative uses for the 555.
The Evil Mad Scientist kits are a great way to learn what's inside it. They are faithful replicas of the internal 555 circuitry, built with discrete transistors and resistors.
You mentioned only ten functional components inside it, but if you look at individual transistors and resistors, there are quite a few more.
Here is the through-hole component version:
https://shop.evilmadscientist.com/productsmenu/652
And a surface mount device version:
https://shop.evilmadscientist.com/productsmenu/922
I built the through-hole version, and it worked the first time I wired up a circuit around it.
Highly recommended!
'10' would be counting the comparator and 2 op-amps as 3 components, the replicas you're pointing at break those out to discretes too, because once you've started down that road, why wouldn't you?
Another link about the internal pars of the 555 https://www.righto.com/2016/04/teardown-of-cmos-555-timer-ch...
You might be interested in http://www.designinganalogchips.com ...
Thanks, I hadn't heard of this book and will definitely check it out!
Well, you can also build microprocessors out of them:
https://hackaday.io/project/182915-555enabled-microprocessor
Probably the first IC I used.
> VCC +4.5 to 15V
With everything going 3.3V these days with no 5V tolerance (can't have nice things ofc), is there some kind of 333 timer that would do the same job but down to those logic levels?
LMC555