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how do you make led's blink and chase? Answered

I would like to use a small cr2032 battery with LED's How many Led's will a 2032 battery run? What about wiring several 2032 in series? and I would like to make them blink and chase ex 1 lights up 2 lights up ect I would like to make them run off a switch that controls steady on blink and chase any ideas would be greatly appreciated. Thanks Christy


Most LEDs draw 20 to 30 milliamps. Most CR2032 batteries give 200 mAh (though the cheaper ones can give as few as 150). So that's one LED for ten hours, 2 in parallel for 5 hours and so on... Rigging the LEDs in series requires a higher voltage. Remember, LEDs in parallel require more current, LEDs in series more voltage.

You can connect two 2032 cells in parallel; that would give you the same voltage, more mAh. Regarding the LED 'chase' effect: Various decade counters will do the trick. Google the phrase 'LED chase' or 'LED knight rider' and you'll find dozens of circuit ideas. If you want to use ten or fewer LEDs, the 4017 decade counter is a good start.

The 4017 IC is your friend for this. Clock one input and it will sequence one of ten lines high sequentially.


9 years ago

The 4001 ic would also handy for this

If you want the LEDs to blink on and off you should look at astable circuits. You can do this with resistors or capacitors or you can buy a cheap IC (integrated circuit) called a 555 which allows you a bit more control. There are good circuits here:

If you want the LEDs to chase each other (do you mean like the lights on knight rider?) then you want to investigate using a 4027 flip flop IC (I think) to make a shift register. This would have an astable as an input and each time it pulsed the next LED would be lit up.

I have some of both of these ICs at home, I might add this to my list of ibles to make.

Wikipedia lists the cr2032 as having a nominal voltage of 3V. It would depend on which LEDs you use. There's an LED calculator that's posted here a lot but I can't find it right now. Help someone?