This must be the first time I've ever referred to the humble 555 as a microcontroller. To be fair, it does have 8 pins and runs at 5V. Maybe a few less transistors though.
Huge processing-power errors aside, this is an interesting and different use of the 555 from normal.
It doesn't use the main output pin, but instead uses the standard configuration to provide a triangular waveform directly from the capacitor.
This is a very retro circuit, but it works well and is fully serviceable at every level, with scope for customisation in terms of PWM frequency and potentiometer range.
The search keywords to find these on eBay are - rgb knob dimmer
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Huge processing-power errors aside, this is an interesting and different use of the 555 from normal.
It doesn't use the main output pin, but instead uses the standard configuration to provide a triangular waveform directly from the capacitor.
This is a very retro circuit, but it works well and is fully serviceable at every level, with scope for customisation in terms of PWM frequency and potentiometer range.
The search keywords to find these on eBay are - rgb knob dimmer
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
https://www.patreon.com/bigclive (extra streams and channel interaction)
Or alternatively:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators
A simple description of the op Amp circuit is it is a comparator since it has no feedback to reduce its gain.
Technician A and Technician B are dressed for surgery with their LED monacles illuminating Grandpa's cranial area, as Grandpa sits catatonic in the operating chair. "What happened to him?" asks A. "He was chewing on an extension cord. Apparently it got mixed up with his late night spaghetti snack." replies B. "Hmm.." says A. "It could be a complete meltdown of the brain circuitry. I wonder what type of BPU chip he has. He's over 100 years old." "I don't know." replies B "It could be one of the original T1000s or maybe an R2D2 variant."
"Here goes" says A as he gingerly prises Grandpa's cranial access panel open with his spudger, ancient hinges creaking as bits of debris and dross fall out onto the floor.
Peering inside, his LED eyepiece illuminating the cavity, technician A uses his air jet to blow away the accumulated dust, exposing the delicate brain circuitry.
"Hmm.." says B, squinting to get a better view. "I don't see any BPU chips at all. It looks like Grandpa's brain is nothing but a bunch of 555s wired together on this piece of perf-board."
(o-] A (o-] B :o] Zzzzz..
why did the algore just show me this? i want 1, i have so much rgb tape and so few drivers and they are all bluetooth phone crap!
A while back we were in a thrift store, and I saw this little box, labeled "DIMMER". They were asking a whopping 99 cents for it, and so figuring that the box was worth that much if nothing else, I bought it. Inside is something that probably resembles what you describe here a lot, I see a voltage regulator, a 555 chip, another 8-pin chip (can't find my magnifying glass at the moment), and a MOSFET. According to the markings on the cover it's rated at 12-24V .8A. No indications of who made it or anything like that though there is some sort of a part number on the board. And a "QC Passed" sticker on the bottom of the box. 🙂
First time I’ve heard of a 555 called a microcontroller – always thought it was just a timer chip.
neat circuit and great explanation of its operation!
…I guess it was more like 15 to 20 years ago…
I had a bunch of these about 10 years (still do) and was mostly impressed with the 555 configuration. IIRC it had three 555's on board and 5k pots.
THE 555 WILL NEVER DIE!
ALSO, you mentioned educational uses…
I built a color clock in which the colors of the LED's mixed as the rainbow (but including MAGNETA). It was a ONE-OUTPUT clock with the colors smoothly mixing acroos the spectrum. With practice, one could get at estimating the time of day from a single color-sum.
I didn't know they were still around.
THANKS FOR ANOTHER GREAT TEARDOWN!!
–dALe
I used 555 timers for dimmers before, but never like this.
I'd use them to drive the MOSFET… one 555 timer for each channel, with lot's of filtering (otherwise you get some nasty flickering… and probably my circuit is crap).
Using their output as a basic waveform input for an opamp is genius.
The values of the pots are usually printed on the front above the shaft . Like 1k-10k-50k etc
An interesting and excellent circuit – well thought out and unexpectedly only one 555 is needed.
I've just completed the design of a dimmer using a 555 and MOSFET, which is adapted from the circuit of a standard buck regulator. Why the complication? Well, the load is a set of 6 SES E14 Bonlux 2 watt LED lamps (see Amazon) that are advertised as 'non-dimmable'. They work on any voltage between 12 and 24 volts, either ac or dc. A PWM feed doesn't work with them because they obviously contain a capacitor that can grab all the charge it needs in a short time, so even if the PWM signal is mostly off, the lamps still operate at full brightness. (This is presumably designed to bridge the gaps when used on 50 hz ac.) The 555 produces a variable PWM signal, controlled by a potentiometer, at about 500 hz., which feeds the adapted buck regulator to produce a variable dc voltage (with a little ripple, which is fine) and the lamps dim nicely with no flicker. Everything is fed from a 12 volt supply, since I don't like mains in the garden.
I could have used a variable linear regulator, but I wanted to keep the efficiency high.
I was thinking, if the positive side of the potentiometers was fed by another voltage divider pot, that could give you a global brightness control that keeps the color proportions intact
One of the classic 555 uses.