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.
You can do almost all of the 555 tricks with comparators and then some, and you'll learn more doing them. Check out the old National Semiconductor application notes for the LM393. You're more likely to see comparators used for little bits of analog/analogish-digital glue in professional designs.
It's excellent teaching material for that reason alone, you do learn about it if you try to understand what makes it tick (there are plenty of articles about it, including blown up versions). I agree it is not the best solution for most applications but I'm happy to admit that I've actually used it in production designs (more than once, actually) where it made good sense to have a component that didn't have to be programmed. If you have a soft component on a board and a spare io line then you are usually better off doing it in some different way.
I've seen some interesting applications of 555s that would have taken a lot more hardware otherwise, one of which was an oven controller with used a thermistor to directly affect the PWM output of a 555.
I was meaning to add footstep-activated lights to my stairs using vibration sensors and 555 timers, but then I learned that if I tried to operate them from a battery, the 555 would drain it in hours, while a much more sophisticated ESP32-c3, would last a month in sleep mode on two coin batteries or one li-ion in the same form factor all while being part of a development board that greatly increases idle current.
That's only true in the very twisted environment that is the modern research university. But universities do still exist which are focused on teaching students as the primary goal, and the faculty there love teaching.
I ended up befriending a former Northrop RF Engineer and a (sadly) homeless genius who was involved in early silicon valley. Those two guys were incredibly impactful on me and got me all the way up to building RF equipment.
I'm really happy that you found an alternate path because such a put-down is terrible and should have never happened in any mature education institution.
My whole workbench is mid to late 90s HP equipment I've picked up very cheap at swap meets. I love this older stuff but it is really crazy what you can buy out of China now. The Rigol Oscilloscopes and Spectrum Analyzers are crazy. They can actually replace a lot of other test equipment and do some pretty complex analysis.
> I'm really happy that you found an alternate path because such a put-down is terrible and should have never happened in any mature education institution.
I actually had a near identical experience at a different university when seeking advice about how to read Hegel. I think this is a common issue with our academic system.
Some people get into Science, Software, and Electronics for the wrong reasons.. And end up miserable teaching after failing in the private sector.
A few 555 can teach people a lot, and burning out parts is part of the learning process. Most fold the DIP legs under like a "dead bug", as that is the tradition to prevent its accidental re-use.
In terms of component cost, ATTINY or PIC10 mcu have internal RC oscillators with configurable PWM pin hardware. Thus a single component is usually better than the accumulated precision error in discreet parts around a 555.
I usually recommend an RC car/truck build, https://eater.net/6502 , and or an LDOmotors Voron kit. Getting your Ham Radio technician license will also introduce you to an intuitive understanding of EE component model limits.
This covers a lot about discreet analog circuits, and I recommend trying to figure out how every circuit works on your own:
https://archive.org/details/encyclopediaofelectroniccircuits...
Simulators are not perfect, but they are a lot cheaper when starting out. =3
Tutorials:
https://www.youtube.com/@FesZElectronics/videos
Tools:
https://www.analog.com/en/resources/design-tools-and-calcula...
https://web.archive.org/web/20200218212700/http://spectrum-s...
This requires a GPU on Windows, but is a more advanced newer Spice simulator:
https://www.qorvo.com/design-hub/design-tools/interactive/qs...
It's one of those poor/early designs like the 741 opamp that has since been superseded by much better chip designs but is thoroughly ingrained in hobbyist and EE101 classes to the point where people think it must be a good design because it's so venerated. It's meme driven really.
However, for educational and hobby use, eh whatever. If I was a professor and the curriculum called for 555 or 741 use I would thoroughly state to the students that A. these devices are historic and good teaching tools, however, in the real world their performance has been surpassed and you would use new designs. Maybe even present a few alternatives like the TL081 and what Pease mentioned for timing.
For learning you some analog, I would recommend the LM358 op amp and the LM393 comparator and all the old National material on them. The LM358 has its quirks so you won't think op amps are ideal but you still see them in a ton of stuff, because they're dirt cheap and adequate for a lot of things, and the LM393 comparator is still so good you really should know why you're choosing anything else - micropower or exotically high speeds or whatever.
Then take a look on 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.
Obligatory link to Forest Mims' book: https://archive.org/details/555-designs
But I would never trust anything that ran software for something like this.
Even if you had to do everything directly with registers, the amount of C or Rust here is minuscule.
I saw this a while ago:
https://www.instructables.com/Designing-a-555-Timer-on-Discr...
Is that what you had in mind?
https://hackaday.com/2011/08/05/building-a-computer-out-of-5...
exactly :)
BF901 FTW.
> 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.
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/
https://web.archive.org/web/20260125061851/http://www.design...
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 )
http://www.designinganalogchips.com/_count/designinganalogch...
Another eatery of Valley folklore is Buck's of Woodside. Neat place on its own.
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.
LeDominoux vid: https://youtu.be/PQOjkuJtBfM?si=pS9Qloekm7JJKCoE
555 contest archive: http://web.archive.org/web/20120121212136/http://www.555cont...
stackghost•1w ago
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•1w ago
ofrzeta•1w ago
15155•1w ago
mrheosuper•1w ago
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•1w ago
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•1w ago
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•1w ago
ErroneousBosh•1w ago
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•1w ago