8 ms·
Doin' It with a 555: One Chip to Rule Them All
- stackghost 8mo agoObviously TFA is satire/tongue in cheek and while you can do all sorts of awesome stuff with a 555 you can't patch those implementations without physically rewiring them which in many cases means throwing out the board and fabbing a new one, whereas a microcontroller-based board can often be fixed with a simple jtag debugger. So, yeah, 555 timers are cool and doing things with analog ICs is groovy but there's a reason everyone just stuffs a small microcontroller in places where we used to just stuff a 555, and it's maintainability.
- nippoo 8mo agoAnd price. A PY32 is about $0.08 in quantity and can do a lot more than a 555 - which is at least 3 times more expensive...
- ofrzeta 8mo agoPuya? First time I hear of these things .. (having used ESP32, RPI Pico, Nordic and STM). Googling led me to OpenPuya https://py32.org/en/ https://py32.org/en/
- 15155 8mo agoPuya is a major flash manufacturer who ventured into ARM chips.
- mrheosuper 8mo agoand it comes with new set of problems: Now you need a FW guys to write and maintain software for it, then your hardware team may need to wait that FW guy to release software to test, or the FW guy need to wait hardware to test his software, etc. Then in production, you need another stage to flash the FW, which add time and complexity. Then security, cheap MCU usually has bad software protection, that means your software can be read out easily, not a big deal since the FW replacing the 555 would be dead simple anyway, but try to explain it to a non-technical CEO when he read about it on his morning's newspaper.
- jeffwass 8mo agoTwo thoughts on situations where the 555 may be preferable, if anyone has experience how these compare : 1. Low-noise applications. I’d naively expect the 555 to be less noisy than a clocked digital microcontroller, though it’s been awhile since I’ve worked in this space. 2. Low power applications. How does latent power draw compare between a 555 and a typical low power microcontroller?
- tdeck 8mo ago> Low power applications. How does latent power draw compare between a 555 and a typical low power microcontroller? The 555 is very power hungry compared to a typical cheap low-power microcontroller. IIRC there are lower power variants but the 555 still fundamentally does timing by draining current through a resistor, which is going to result in losses.
- dubbie99 8mo agoA micro is far superior on both these metrics.
- ErroneousBosh 8mo ago> I’d naively expect the 555 to be less noisy than a clocked digital microcontroller TTL ones were exceptionally noisy because the output transistors "shot through" - both output transistors would conduct for a moment shorting the supply rail to ground and crowbarring ridiculous interference onto other parts of the circuit.
- buescher 8mo agoAnd there's another reason not to recommend them - no one sane has used the bipolar version since the Carter administration but they're still out there and it's another pitfall for beginners.
- nurettin 8mo agoObligatory https://youtu.be/mDhNQPt8An0?si=VlzHWK4Cxcxn9pSK https://youtu.be/mDhNQPt8An0?si=VlzHWK4Cxcxn9pSK
- solomonb 8mo agoWhen I was in college I was not in an engineering program but I was self-learning electronics. I was trying to learn to use a 555 timer to do something and couldn't get it to work. So I went to the office hours of a random EE professor thinking they would help me out. Instead I got scolded about how 555 timers are not real engineering and that I shouldn't waste his time. I never used a 555 timer ever since.
- foxglacier 8mo agoI used to salvage components from electronic stuff and was always looking out for 555s but never found any, in a whole range of vintages from 1970's to 2000's. I ended up with the same conclusion - it seemed to be a hobbyist's chip that real consumer products didn't use and felt amateurish for some reason I didn't understand.
- tralarpa 8mo agoThat's funny because I have two objects on my desk for which I know that they use 555s. One is a no-name joystick with "autofire" function from the late 1980's. The other is a mass produced motor controller from the 2000's where the 555 generates the PWM signal for a FET.
- leoedin 8mo agoThe big problem I ran into playing around with 555s was that capacitors are very rarely the capacitance they claim. Unless you're speccing an expensive capacitor, you'll find your time constant varies quite a bit across devices and temperature. That's fine for some use cases, but completely a deal breaker for others.
- buescher 8mo agoYeah, in the typical value ranges (nanofarads) of a 555-timer-class analog design, you'll need film caps. Ceramic C0Gs are too small and class 2 dielectrics are dismal for anything but bypass. They don't just have temperature coefficients, they have voltage coefficients and are wildly nonlinear. And electrolytics are almost as dreadful as batteries. Worse in some ways. It's a tough bridge for beginners to cross - once you figure out capacitors are not all equivalent you have to do a deep dive on dielectrics and it's a bit of a chicken-and-egg problem - you don't know what you're doing so you don't when you'll need what.
- ryan42 8mo agoI want to build an atari punk console with a 555 to learn basic soldering and electronics, fun stuff
- ErroneousBosh 8mo agoDo it. Build a couple, then build a simple opamp mixer (it's a single opamp and a handful of resistors, and a couple of capacitors across the power supply), and then - get adventurous - a PT2399 delay kit. Then take a look on https://yusynth.net https://yusynth.net at some of the VCF designs, and build one of them. You won't have a synthesizer, you'll have some crazy homebrew drone machine that you can make scary movie sountracks with.
- 0xEF 8mo agoDefinitely do it. Obligatory link to Forest Mims' book: https://archive.org/details/555-designs https://archive.org/details/555-designs
- cbdevidal 8mo agoAh man I had that one. Total flashback when I opened your link. Thanks
- fzeindl 8mo agoThe 555 is a versatile little thing. I used it at university for a simple circuit which allowed an arduino to cut it’s own power for 5 minutes and then boot again.
- pkphilip 8mo ago:) that is actually pretty cool!
- gary_0 8mo agoI designed the electronics for a heavy-duty industrial 3D printer and used a 555 in the failsafe circuit (alongside the manual e-stop). If it didn't get reset by a heartbeat from the embedded computer/software, it would unpower the heaters and actuators.
- buescher 8mo agoThat's the only use for one that isn't (always) a design smell - it makes a really nice missing pulse detector, better than you can easily do with comparators. But if you have the budget, a purpose-made watchdog chip or a tiny microcontroller really can make a better watchdog.
- gary_0 8mo agoI would absolutely not want to use a microcontroller or a complicated chip for something like that. Simplicity is the point.
- buescher 8mo agoSupervisor chips are not complicated. In some ways simpler than a homebrew analog watchdog, and the good ones will handle failure modes a simple watchdog won't, like those that result in an oscillating output.
- gary_0 8mo agoYes, a simple purpose-made chip designed to be used in safety-critical situations, with high tolerances for voltage etc, would probably be better. Although one thing the 555 design has going for it is that a seasoned EE could take one look at the physical circuit and know exactly what it does. But I would never trust anything that ran software for something like this.
- buescher 8mo agoIt depends on the system's potential failure modes and what's required by your safety standard, not on one engineer's opinion of what's "best".
- reader9274 8mo agoI built one from discrete transistors in a lab class in college, on a breadboard. Fun times debugging and getting it to work. Then I flashed an led with it right next to another led flashed from a 555 chip. With the same discrete timer caps, the flashing frequencies were different due to the extra parasitics in the breadboard discrete 555 version. So had to compensate the caps to make the flashes match each other's frequency.
- jacquesm 8mo agoThat's a great exercise. The hard part is always that in chips you can pull stuff that is rather tricky discretely, for instance, a multi-emitter transistor. So you can't always do a 1:1 conversion but for a 555 it is still doable. I saw this a while ago: https://www.instructables.com/Designing-a-555-Timer-on-Discrete-Elements/ https://www.instructables.com/Designing-a-555-Timer-on-Discr...
- direwolf20 8mo agoOnly because odd components aren't marketable. There used to be 4-terminal MOSFETs, they weren't sold after ICs became normal. Never heard of a multi emitter transistor being sold discretely but it's possible.
- jacquesm 8mo agoI use dual gate FETs frequently for all kinds of tricks and they're super useful. Is that what you had in mind?
- squarefoot 8mo agoDual gate mosfets were a godsend when building RF/IF mixers or preamps. Luckily I have a small stash as they're almost unobtanium and costly these days, but for most uses such as mixers and preamps they can be swapped with a pair or normal jfets in a cascode configuration like this one: https://i.stack.imgur.com/6Nyhg.gif https://i.stack.imgur.com/6Nyhg.gif
- pantulis 8mo agoHave to love the tone of the article.
- aj7 8mo agoThe late Harold DuBose of Spectra-Physics, repeatedly used 555's as power inverters in the electronic design of a frequency stabilized ring dye laser. He liked the strength of the output transistor.
- deleted 8mo ago[deleted]
- MeteorMarc 8mo agoIn the same voice as saying that some language is Turing complete, we can now say that an electronic component is 555 complete.
- quijoteuniv 8mo agoThat’s why the Beach Boys made a song about the 409, the predecessor chip.
- TomMasz 8mo agoThe 555 figured prominently in a digital circuits course I took back in the mid-80s. It was into its second decade of existence by that point, and it's still going strong.
- BoredomIsFun 8mo agoDepends what you want to achieve; from fundamental educational point of view it is not a good device, too high level; most of the stuff you can build with 555 you can do with standard BJTs, and you'd be able in fact in understand how it works. To me, 555 is good only for dumbed down entertaintment, not true learning.
- nayuki 8mo ago> Doin’ It With A 555: One Chip to Rule Them All > We also know that microcontrollers implement logic gates – AND, OR, NOT, NAND, etc. But you don’t have to deal with those complicated logic functions, or worse, the software that runs on those microcontrollers. Get down to brass tacks and use hardware (555 ICs and 555 timer ICs, to name a few the only important ones) that just works! Come on, you haven't even described how to implement combinational logic using 555 timer chips. Just show us how to build NAND, please.
- aashvik 8mo agoSorry. That topic's reserved for the sequel, "Implementing RISC-V in Only 870,000 555 ICs, Part 1 of ??".
- jrmg 8mo agoThe ‘birthplace’ of the 555 is in downtown Sunnyvale - an easy trip if you’re in the Valley*. It’s in an alley between Murphy Ave. and the parking lot off S. Frances. There’s a realtor’s office opposite the side entrance to Fashion Wok. That’s the place. It was invented by Hans Camenzind**, who was doing contract work for Signetics in an office he rented there. What a great location for your office, even back then! There really should be a plaque or something. * Go there then have dinner at Dishdash, across the street. ** RIP - he died in 2012, but his web site is still up: http://www.designinganalogchips.com/ http://www.designinganalogchips.com/
- asdefghyk 8mo agoInteresting links on Hans https://web.archive.org/web/20260125061851/http://www.designinganalogchips.com/ https://web.archive.org/web/20260125061851/http://www.design... https://en.wikipedia.org/wiki/Hans_Camenzind https://en.wikipedia.org/wiki/Hans_Camenzind ( Please note , I posted the archive.org link to the Hans Camenzind site, because when I tried to access the site URl , my BitDefender virus thing popped up a warning about a certificate problem. I Have NO idea if this is a real problem (Im clueless) or not but just to be careful I use the archive.org link )
- madison256 8mo agoHans wrote a text book, "Designing Analog Chips" which is available for free. http://www.designinganalogchips.com/_count/designinganalogchips.pdf http://www.designinganalogchips.com/_count/designinganalogch...
- burnt-resistor 8mo agoCool. I lived on E Evelyn for a few years in the 00's and dined many a night at Gumba's. And Hobee's and Denny's of course. I miss the days of raiding Radio Shack in the nearby mall perennially under construction for piles of :CueCats. Another eatery of Valley folklore is Buck's of Woodside. Neat place on its own.
- jrmg 8mo agoGumbas is still there! Hobee’s near 101 too. Still my favorite diner. The mall (and ‘downtown’ Denny’s) has finally, after literal decades of construction driven by multiple bankruptcies of the firms doing it, been replaced by walkable mixed use stores, apartments, and a cinema.
- ChrisMarshallNY 8mo agoI'm really looking forward to the LLM results of all these posts.
- aashvik 8mo agoAuthor here, my posts are typed entirely by hand. I only ever use LLMs for consultation, so anything awkward here is, well... artisanal.
- relwin 8mo agoI won 2011's "555 Timer Contest" artistic category. As a bonus I got a phone call from Hans Camenzind, who offered to design a custom chip (for free) to perform the same function. LeDominoux vid: https://youtu.be/PQOjkuJtBfM?si=pS9Qloekm7JJKCoE https://youtu.be/PQOjkuJtBfM?si=pS9Qloekm7JJKCoE 555 contest archive: http://web.archive.org/web/20120121212136/http://www.555contest.com/news/ http://web.archive.org/web/20120121212136/http://www.555cont...
- effnorwood 8mo agohttps://m.youtube.com/watch?v=bjAlzA4Cyys https://m.youtube.com/watch?v=bjAlzA4Cyys
- bzmrgonz 8mo agoWait, so this is not April fool's? I read April 1st and bolted.
- aashvik 8mo agoIt's entirely satire :)