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A circuit for randomly lighting LED? Answered

Hi all

I am a newbie in analogue and I would like to make something for hobby.

I would like to build a circuit with breathing lighting effect for 5 to 6 LED, and they breath individually at random time, so to create some random lighting effect, and the circuit may be powered up by a 3V battery.

So how can this individual random time for switching the LED on and off done please?



8 years ago

I'm doing something similar in THIS Instructable. The LEDs flash randomly - Really easy to do with a Picaxe microcontroller.
The 08m chip I'm using actually has only 3 LED outputs, but the similar 20m has 8 outputs - Ideal for what you want.  The Instructable gives a fair bit of info on the Picaxe. 


Answer 8 years ago

thank you for your reply, it seems to need some time to understand how to program the microcontroller, so do u believer that I can use this microcontroller to create the random breathing effect on several LEDs??

By the way, I did some search outside this forum, ppl seem to use a 555 timer to do this effect, but if I follow this method, does it mean I will need 1 timer per 1 LED I have on my design please?


8 years ago

Use an arduino with a pseudo-random number generator subroutine. Sounds fancy and complex, but it's not. Cost you maybe $39? (someone correct me on that dollar amount) for the arduino. At a guess, the arduino either has a canned routine or one can be downloaded from someone, or, alternatively, written yourself. There are many many webpages that investigate random number generation code.


Answer 8 years ago

is it possible to do this task with only some analogue and possible a simple microcontroller?


Answer 8 years ago

Yes, you can do pseudo random generation using a a hybrid or pure analog circuit. It's just such a pain and arduinos seem to be popular here at instructables that I punted for an arduino.

AndyGadget uses a picaxe as he shows above (and he even offers up a very nice instructable, not something I'm likely to do). I'd use whatever I had my hands on be it a picaxe, an arduino, or some other microcontroller microprocessor, etc, or hybrid/analog circuit.

But detailing an analog circuit for you isn't something I'm willing to do. Too much work for too little gain. That's why I got a degree, so *I could do this sort of thing. Get a degree and you can too. Otherwise search the net or use the off-shelf hobbyist tools.

No offense intended with my comments.

I'm voting for Andy and suggesting that you use his instructable.