Need help for any circuits which can turn LED on/off

[giraffu]

Timer.

May i know if is there any circuits which can turn LED on for 12 hour and off for another 12hour? What can i do?

 

[IanP]

Re: Timer.

The easiest way is to use a microcontroller ..
For example, PICAXE has a command called WAIT that produces 1s delay ..
If you repeat this command for 60x60x12=43200 times it will give you 12h delay ..

IanP
:idea:

 

[giraffu]

Re: Timer.

Oh but i want this particular LED to on from 6pm to next morning 6am. And off from 6am to 6pm. This process is repeated over time.

 

[IanP]

Re: Timer.

In this case you have to add an RTC (real-time-clock) ..
Examples:
DS1302 with SuperCAP
or
DS1307 with 3V lithium battery

IanP

 

[Tahmid]

Hi,
In this case you need to have an RTC (DS130x, PCF8583, etc) and a microcontroller (PIC, AVR, anything) which checks the time and determines when to turn the LED on/off.
You should start by deciding which microncontroller to use, the programming language, and then the RTC interface.

Hope this helps.
Tahmid.

Added after 4 minutes:

Hi,
Something simpler would be, no RTC and only micrcontroller. The microcontroller will have a trigger switch, which when pressed will turn the LED on and turn it off 12 hours later, turning it on again 12 hours later.
You can press the trigger switch at 6pm and hope to keep the circuit working as long as your power supply is present.

Hope this helps.
Tahmid.

 

[KMoffett]

Assuming you have access to line power, a simple solution, if you can tolerate the size is an electromechanical or digital wall plug timer. Plug a wall-wart, with a suitable DC voltage and current rating to power the LED(s ?)into it, and set to on/off times.

Ken

 

[pcwortex]

try using NE555

 

[Wxy8030]

PIC12F508，with a external 32.768K Crystal. That's enough !