555 Timer Circuits

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.

> 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 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.

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).

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.

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.

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.

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.

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.

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!

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

Link to your kits?

Seconding this.

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.

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.

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.

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.

> 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?

> 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).

> 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!

>>> 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.

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.

... 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.

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.

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.

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’d imagine pretty common, at least back when it was uncool to be a “nerd”. Hormones are a powerful drug, and at least until I figured out what it was all about, girls were way more fascinating than electronics.

Sex derails the potential of young humans in so many ways, yet the process of reproduction is so arduous that it makes sense that we’d end up wired to prioritise it heavily. All it would take is for young people to wise up and we’d be extinct within a century and a half lol.

We’re seeing the results of not valuing the labor that is creating a home and raising children in systematic rapid population decline. (Which might seem ok, but in most situations, it is socioeconomicly catastrophic)

We need to learn to overtly value the huge labor sink investment that motherhood , fatherhood, and family stewardship entail.

There are things more valuable to humanity than the ability to concentrate wealth and power at the expense and to the exclusion of others.

The whole drive to concentrate wealth and power is fundamentally based on sex anyway. It seems a great poverty to not acknowledge and socially celebrate the skills, labours, and sacrifices of parenthood.

> Often a BJT or power fet is all they need (say for a basic relay trigger).

Perhaps you mean BJT+resistor+diode+relay or FET+diode+relay is all they need?

The value in the module is that it includes the necessary components required so that the circuit doesn't break. And such breaking is highly destructive to the learning process. You need to get kids excited about what they might be able to do on a larger scale, before you can trick them into studying the lower level details and diligence required to make it happen.

My own childhood explorations in electronics were stunted due to not understanding that BJTs were current devices, and what all those resistors were for. I'd try to modify a circuit, destroy a transistor, and then no amount of playing around would get things working again. Especially on those toy kits where every component was broken out into spring terminals - I basically learned that the transistor section was verboten unless I was building something exactly from the manual. Sometimes I ponder how much earlier I would have understood electronics in an alternative timeline that emphasized 2N7000's instead of 2N3904's.