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Problems with delay and timer for led circuit

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Junior Member level 3
May 31, 2002
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Delay and timer help!!

I want to build a circuit that when i start it the led will stay off about 30 sec. then it wil illuminate 1 min. and then it will go off.It will lock the start button i mean when i give another pulse it will not accept the second one.I tried to build it with 556 but nonsense.
Please hellllpppp!!!

One way would be to use a PIC12C508 8 pin micro. You could make that do what ever you wanted.
Maybe overkill??

Yes i thought that a 8 pin mcu is very fine for it but cost is important :(
So to program is an additional cost for it.Because i need a guy to program it.I will build it many times.Thanks for reply
I don´t understand if you like the idea of the µC but it only cost about 2.5€
for the OTP version. Another way is to use logic devices. If you are using main (220V/50Hz) you´ll can retrive a 100Hz wave (from the retifier bridge) and with an 74HC390 you´ll get both 500mS and 1S times. Then add a S-R flip flop and you´ll get what you want.

You used 556 in ordrer to produce the two timing 500ms and 1s? Why not using a crystal instead? I support the μC option, it is cheap but if you don't how to use it and you have to learn turn either to a quick learning μC-I suggest motorolas HC05 or Atmels905-. On the other hand logic design is a quick, cheap and convinient idea as Elavionic suggest!

Have a nice work!!!

PS: In HC05 there are ready programms to introduce delay time!To be more specific the Application Guide book introduce you to HC05 with a programm application similar , if not the same to your request.Try motorolas site to be sure for it!

8) 8) 8)

I think I got a solution, the good old R-C and a couple of comparators instead of 556. If you're interested I may send you a schematic
We'll see how it works

Errm..I think you misunderstood sirs, because i'll build this circuit many times and i dont have time and effort to program it.I need a schematic that contains dummy components.
If you send that circuit i will be appreciated..Thank you :D

Hi ergen,

To be honest I don't understant what you want, maybe I'm stupid ... :oops:

You write "I want to build a circuit that when i start it the led will stay off about 30 sec. then ......" :eek:

When nice guy's here try to help you .... :D

You answer "I think you misunderstood sirs ..............I need a schematic that contains dummy components" :x

And you add "If you send that circuit i will be appreciated..Thank you" :roll:

No coments!

:lol: :lol: :lol: :lol: :lol:

I simulated the circuit, but you have to try it for real. You may also need to change the values of some components.
Another thing, the circuit should work well, but don't pretend great accuracy.
pm me to tell where should I send it, or wait until FM comes back

best regards

decade counter can help you!!!

you can do it with 4017 decade counter and 555 with f = 1/10s.
this decade counter have ten decoded outputs (Q0-Q9)that are normally low and one pin go high for 10s and so one it olso have clock enable that can stops the count at the end by putting Q9 to Clock enable you also need 6 diodes (working like logic AND) from Q3-Q8 and then to the LED
and you can lock the key by adding jk flip flop and then to the reset.

PIC CHIP is a good way to go, man, if it aint got a micro in it.
I could program that sucker during tea break!

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