I want a accurate timer which can switch the led at regular interval.
for eg : If I set the timer at 2pm then it should glow the led at exactly 2pm and stay for 2 hours... and after 2 hour it should automatically switch off the led and this should repeat everyday....
and we can also vary the time when needed and it should give 2 hour delay..
Further questions:-
What time resolution/accuracy is necessary (microseconds, seconds, minutes....) for both the time of day and the LED 'on' time?
What is this "2 hour delay" you've just introduced? When does it start? Is it just another way of referring to the LED 'on' duration?
see the attached pages, its all about a digital alarm clock and a timer, combining both you can make what you need. as every one suggested not easy to assemble, since you have the interest you can invest your time on this..
Further questions:-
What time resolution/accuracy is necessary (microseconds, seconds, minutes....) for both the time of day and the LED 'on' time?
What is this "2 hour delay" you've just introduced? When does it start? Is it just another way of referring to the LED 'on' duration?
Now I think you're overloading the questions just a little bit.
From what I've read, I think it's safe to ASS-U-ME that ordinary household clock accuracy is plenty good enough here (for both the on and delay times).
The 2-hour delay is just that: from the instant the LED is turned on, it will be turned off 2 hours later (to the accuracy stated above).
Now I have no clue where yusuf is located but everyday programmable timers in many flavors like these are available I would think globally. I can't build one for what I can buy one for. They are all easily hacked for your construction (or destruction) pleasure. I see timers out there for $11 USD that I can't begin to build for that price.
Now I have no clue where yusuf is located but everyday programmable timers in many flavors like these are available I would think globally. I can't build one for what I can buy one for. They are all easily hacked for your construction (or destruction) pleasure. I see timers out there for $11 USD that I can't begin to build for that price.
Yeah, I know. Eric in post #6 suggested using a uA2240C and for reasons I don't understand that suggestion was ignored. Oh well, I guess a bowl of ice cream is in order.