▲5:55 video released on May 5th, as per description :)
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.
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.
There's a lesson in there somewhere.
FarmerPotato6 hours ago
[-] Two videos tomorrow at 5:56!
reply▲That's fine, but you know you have to concatenate them and sell them as one unit, right?
reply▲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 :(
reply▲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.
reply▲The port that was standardized on for PC joysticks was the dumbest possible one:
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.
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.
[edit]
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.
SoleilAbsolu6 hours ago
[-] 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!
reply▲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.
reply▲Built an atari punk console using these with my late father. Still have it hanging on my wall in a shadow box.
reply▲I recently dug one out to use as a hardware shutdown timer to power off an rpi's PSU once it has presumably halted without having to resort to a dedicated MCU for the task.
reply▲Oh god I feel old. I remember being an excited schoolboy thinking how magic this was when it debuted.
reply▲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.
reply▲Ha. When I was a teenager I used to build 555s into timers for the same purpose using a no PCB rats nest construction.
Though surprising the family at dinner with a small explosion was a much more innocent purpose.
Brian_K_White5 hours ago
[-] For me that is blue leds.
reply▲"rareleds" on Instagram is fantastic. Vintage LEDs set to apex twin and so on
reply▲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."
reply▲The 555 timer is
still the most popular chip that hobbyists add to their parts inventory (see rankings at
https://partsbox.com/ecdb.html). 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.
One nice thing about the 555 is that at least it aged well and still is very usable in those beginner tutorials. Unlike for example the uA741 which no one should use.
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.
reply▲That says a lot more about them than it did about you.
reply▲also today's date is 5.5. and the video is 5m55s
reply▲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.
reply▲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
reply▲Just another 500 years to go. I missed the beginning, probably will miss that last milestone as well.
reply▲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.
reply▲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!
reply▲What component values do you need to time exactly 55 years?
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. :)
reply▲I don't think you could do it. Not with the original BJT variant anyway. :)
reply▲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 ;-)
https://www.digikey.com/en/products/detail/tecate-group/PBLH...
Time to slow it down to lower frequencies and give it more frequent checkups.
reply▲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.
reply▲killer oneshot, laughed hard..
reply▲I used to get exited about this. Hahaha I think I miss those days.
reply▲raverbashing5 hours ago
[-] Makes me wonder if we could have a 555 circuit with a trigger time of 55 yrs
reply▲How many capacitors do you have that can hold their charge for 55 years?
reply▲Every EEPROM is basically that, and they're designed for data retention of around 100 years. I imagine it wouldn't be hard - embed two metal plates in glass?
reply