5:55 video released on May 5th, as per description :)<p>For something feeling like a fairly specific IC, I remember seeing many projects that use it throughout the years in wacky ways - and seeing it makes me happy to know that the sentiment for this little piece is shared.
I learned (long ago) it’s trivial to fool my satellite receiver’s modem’s dial tone verification for remote pay per view ordering (it doesn’t phone home right away but gets angry if it’s not connected to a phone line).<p>Turns one a single frequency that’s remotely close to one of the two tones of a dial tone will convince it. Wasn’t sine wave either but not a problem! 555 powered by a 9V battery.
The trick is that it's sold as a timer but it's really a kit of parts from which you happen to be able to build a timer.<p>There's a lesson in there somewhere.
Two videos tomorrow at 5:56!
my favorite use of a 555 is in a solar charge controller. It is a voltage controlled switch!<p>i have the page archived, but it's called A New Solar _ Wind Charge Controller Based on the 555 Chip (2_7_2026 12<p>I can upload the webrip if anyone wants it
Big Clive is currently livestreaming to celebrate the 555's birthday: <a href="https://www.youtube.com/watch?v=jzNjFJdaw_I" rel="nofollow">https://www.youtube.com/watch?v=jzNjFJdaw_I</a>
You can learn about the origin of the 555 timer from its creator in his free book here: <a href="http://www.designinganalogchips.com/" rel="nofollow">http://www.designinganalogchips.com/</a><p>Fun fact: his original concept needed 9 pins and therefore was going be forced to have a 14 pin package. A late epiphany got it down to the 8 pin version we know today.
I still have the Forrest Mims III Radio Shack "555 Engineer's Mini-Notebook" somewhere in my basement. And rumor has it that Sammy Hagar can't drive 555 because his car just isn't fast enough!
I have a paper copy of "IC 555 projects" kicking around on my bookshelf still!<p>PDF version here <a href="https://worldradiohistory.com/UK/Bernards-And-Babani/Babani/Bababi-IC-555-Projects.pdf" rel="nofollow">https://worldradiohistory.com/UK/Bernards-And-Babani/Babani/...</a>
The Mims books are fantastic. As a kid I collected every mini notebook and the green Radio Shack "Getting Started in Electronics." They were my intro to electronics along with the Radio Shack kits.
Also consider the <i>IC Timer Cookbook</i> by Walter G. Jung.
As a kid I didn’t understand what the 555 timer chip on the Apple II disk controller was doing but I learned the hard way that when you misalign the pins on the drive connector cable and the 555 chip releases its blue smoke you can’t use the drive anymore :(
I have read as well that the 555 was used in the game paddles for the Apple II. 555 + potentiometer (the part you turned) varied the length (duty cycle?) of a square wave which the Apple II used to determine the paddle position.
The Apple II family did indeed use 555 timers, in either 558 or 556 chips, to drive the timing circuit used to read paddle and joystick positions. The following article explains both the circuit and the reading code:<p><a href="https://www.applefritter.com/appleii-box/APPLE2/NibbelingAtTheGameport/NibbelingAtTheGameport.pdf" rel="nofollow">https://www.applefritter.com/appleii-box/APPLE2/NibbelingAtT...</a>
The port that was standardized on for PC joysticks was the dumbest possible one:<p>The joystick itself just had 1 potentiometer per axis, wired directly to the port. The port had no A/D, no timer, and no interrupt. Instead there was a GPIO and a capacitor. You discharged the capacitor with a GPIO write, and then polled the GPIO to measure when the capacitor was charged again. The number of iterations through your polling loop would be proportional to the position of the axis.<p>This is a pain to emulate if you aren't doing cycle-accurate emulation. IIRC Dosbox has a bunch of kludges and still doesn't get the joystick right for every game.<p>[edit]<p>To clarify the game port used a 558 (quad stripped-down version of a 555) as a schmitt trigger, so it generated pulses of a width proportional to the potentiometer position. I looked up the Apple II interface and it looks very similar, but with the caveat that accelerated versions (e.g. the IIgs) would always clock to 1MHz when reading the joystick port, compared to the PC that could run at a huge range of clocks (and CPI) over the lifetime of the port.
I remember using similar trick to use LEDs to sense light. Basically, charge the (reverse biased) LED capacitance, then measure how long it takes to discharge.
The lil circuit I had was LED bar, so I used it to sense finger position using that (other leds providing light, LED doing the sensing judging that light and comparing to rest
Yea, definitely don’t let out the magic smoke. That stops all the fun right away.
There was a 556 on the Apple ][ disk controller (a dual 555).<p>See: <a href="https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/Disk%20Drive%20Controllers/Apple%20Disk%20II%20Interface%20Card/Schematics/Apple%20Disk%20II%20-%20Schematics%20050-0005-01.pdf" rel="nofollow">https://mirrors.apple2.org.za/Apple%20II%20Documentation%20P...</a>
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Evil Mad Scientist makes a giant, discrete version as a soldering kit:<p><a href="https://shop.evilmadscientist.com/productsmenu/tinykitlist/652" rel="nofollow">https://shop.evilmadscientist.com/productsmenu/tinykitlist/6...</a><p>Very cool. (Looks like it uses 26 transistors. I assume the die is similar.)
Built an atari punk console using these with my late father. Still have it hanging on my wall in a shadow box.
Oh god I feel old. I remember being an excited schoolboy thinking how magic this was when it debuted.
For me that is blue leds.
Yes! I remember thinking "damn you band gap physics, if we only had blue leds we could do colour displays with LEDs, but that can never happen."
"rareleds" on Instagram is fantastic. Vintage LEDs set to apex twin and so on
I also remember being amazed, and did a forehead slap, when an old army bomb disposal man explained how, what I thought was an innocent device, was used by the IRA in bombs.
I got lucky I saw and screenshot when this had 222 points with 55 comments.<p><<a href="http://ibb.co.com/1Y7QFB8N" rel="nofollow">http://ibb.co.com/1Y7QFB8N</a>>
I used one of these to win an inter-school science competition when I was ~13. It was a minute timer. The competition board doubted I had built it all myself, so they plonked it down in front of me and demanded I draw the circuit diagram in front of them.
I was on my college fencing team. One summer, I had an internship at HP and they paired me with a grizzled old hardware designer, Fred, as a mentor to build a summer project. Fred had a lab bench with drawers overflowing with old resistors, caps, ICs, and even some tubes (“Fred, what the hell are you going to use those for?” “You never know. Tubes might come back!”). Fred had once accepted a promotion to be a manager and quickly renounced it because he hated it and just wanted to design hardware. I decided to build the electronic scoring system used in fencing matches. Our school had one professional system, but I figured I could replicate it for a lot less money. It was all based on a couple of 555s, some 74-series TTL counters, a few LEDs, buttons, and a speaker. Fred was the guy who showed me how a 555 worked. I built it, it worked, and the school used it for at least a year or two after I left. Happy memories. God bless Fred, wherever he is.
The 555 timer is <i>still</i> the most popular chip that hobbyists add to their parts inventory (see rankings at <a href="https://partsbox.com/ecdb.html" rel="nofollow">https://partsbox.com/ecdb.html</a>). I find this both interesting and curious — I'd say it has mostly nostalgic value at this point. Almost every practical problem today is better solved by something else. And yet it persists, I guess mostly because of beginner tutorials and first LED blinky circuits.<p>One nice thing about the 555 is that at least it aged well and still <i>is</i> very usable in those beginner tutorials. Unlike for example the uA741 which no one should use.
> Almost every practical problem today is better solved by something else.<p>I'm curious about this claim. It's certainly easier to just wire up a modern microcontroller, but is there a better option that involves no software and is likely to still work the same today as it did 50 years ago?
I find it much easier to write a ten line program for an 8 pin CH32V003 (or ATTiny85 in past times) to do exactly the timing or SDC comparisons I want than to figure out the circuit and component values for a 555 or op-amp.<p>For that matter, a 16 pin CH32V003 can emulate a vast array of 7400 series devices as long as you don't need ns timing — no problem for µs. It's also cheaper.
also today's date is 5.5. and the video is 5m55s
I have a Displate of a decapped 555 hanging near my EE workbench:<p><a href="https://displate.com/displate/2002057" rel="nofollow">https://displate.com/displate/2002057</a>
Back when radio shack still existed I would buy a 555 timer during every visit. I live collecting them and still have a bunch somewhere stored. I continue to do it with the 328p arduino boards as well whenever I visit my local microcenter.
As an electronics-enthusiast kid in the 70's, just before home computers showed up at all, I wished the 555 was for Time Travel
When I was a camp counselor in my 20s I designed a one-octave "piano" out of one of these, a battery, paperclips for keys, and a shitload of resistors. We had the kids build them on proto board. They sounded harsh but you could play Mary Had a Little Lamb on them!
Can't watch it right now, but upvoted for Dave Jones. He's taught me so much. Absolute treasure, and the host of one of the last great active forums. Thank you for not blackholing all that info on the disaster that is Discord, like so many other communities.
!remindme 500 years
What component values do you need to time exactly 55 years?<p>Maybe it could work if you used 5 timers?
How exactly is exactly? Can I make it measure 1 hour with an allowed tolerance of 55 years, plus or minus. :)
I don't think you could do it. Not with the original BJT variant anyway. :)
Hmm, why not? For the astable configuration, you could use a 100F capacitor with R1 = 10 Meg and R2 = 7.5 Meg, for a 55 year period. Base current for the Threshold NPN will come from the Trigger PNP (and hopefully temperature drift matches OK). Other than maybe the 100F capacitor might have some variation in capacitance and leakage current over the course of 55 years ;-)<p><a href="https://www.digikey.com/en/products/detail/tecate-group/PBLH-12R0-100ST/12323423?s=N4IgjCBcpgnAHLKoDGUBmBDANgZwKYA0IA9lANogAMIAugL7EBMVALEtCGpFnkaRRDwqAAgBiIYmCqiJtYgAcALlBABVAHYBLJQHl0AWXyZcAVwBO%2BEIxAsA7B1QYcBYmUiUwTEQDU6ilUh1bT1DYzNLa2IAWiZkLiglc1N%2Bd0oAVjp6bKA" rel="nofollow">https://www.digikey.com/en/products/detail/tecate-group/PBLH...</a>
Time to slow it down to lower frequencies and give it more frequent checkups.
And the topic had 55 comments when I first looked at it
killer oneshot, laughed hard..
The late Harold DuBose use to use the 555 as a power inverter as it could sink 200ma at the laser companies he worked for. Convenient and cheap.
I used to get exited about this. Hahaha I think I miss those days.
Just another 500 years to go. I missed the beginning, probably will miss that last milestone as well.
Makes me wonder if we could have a 555 circuit with a trigger time of 55 yrs
and this is the fifth comment