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556 Timer project

chess

Oct 11, 2011
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Oct 11, 2011
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Hi

I want to illuminate a series of LEDs at approx one minute intervals, one after another. A switch to start and a switch to turn off. I think that the 556 would be a good start but I really have not got a clue how to do this. When not in use low battery power is essential.

I would appreciate some help or alternative suggestions, thanks.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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25,510
How many LEDs?

I would look at PICaxe, Arduino, or similar.

Doing it in a analog manner would be tricky considering the time delays involved (thinking constant current charging capacitor and something like an LM3914).

A digital approach would take many more chips. Oscillators, dividers, counters, etc.

edit: 555 design could entail the use of monostables, but the long delays involved would mean that timing would be approximate and variable (at the mercy of environmental and other factors)
 

KJ6EAD

Aug 13, 2011
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1,114
You can make a sequencer using a 555 and a 4017 decade counter.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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True. I had misread that there was a long delay at the beginning. If not, this is a simple 2 chip solution. The caveat about long delays still applies.
 

chess

Oct 11, 2011
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Oct 11, 2011
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Thanks

I need 8 LEDS, the first to come on at the start, interval could be +/- 5 sec. Thanks for your suggestions, I was aware of PIC chips but did not want to have to get into assembler if I can help it.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Picaxe chips are programmed in something like BASIC. Arduino in something like C.

I'd give the 555/4017 solution a go. It will allow you to have up to 10 leds, which exceeds your requirements. The only issue is that if you leave it long enough, it will start from the beginning again.
 

chess

Oct 11, 2011
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Oct 11, 2011
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Ok, thanks I will look at the counter. Thanks for the information, Basic is good.
 
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