Circuit auto OFF feature after no events design - Electronic Circuits Projects Diagrams Free

Uman · 2nd May 2004, 12:25 PM

A hand held circuit detects the presents of an object using an IR emiter and transistor detector. The circuit is powered by a 9v battery and sounds a buzzer when the IR light beam is interrupted.
I would like to add a feature to auto OFF the circuit when no objects interupt the IR beam within 60 minutes, to conserve batteries. The power switch will be cycled to activate the circuit again.

I suspect a 555 timer circuit embedded in the above circuit is the solution. Is the 555 timer the way to go or is there a better way?

Is it possible for the circuit to automatically reset the 60 minute timer after each interrupted event and power down after 60 minutes of inactivity?

Thanks,
Jeff in Florida

**Nigel Goodwin** · 2nd May 2004, 08:37 PM

Quote:

Originally Posted by Uman

A hand held circuit detects the presents of an object using an IR emiter and transistor detector. The circuit is powered by a 9v battery and sounds a buzzer when the IR light beam is interrupted.
I would like to add a feature to auto OFF the circuit when no objects interupt the IR beam within 60 minutes, to conserve batteries. The power switch will be cycled to activate the circuit again.

I suspect a 555 timer circuit embedded in the above circuit is the solution. Is the 555 timer the way to go or is there a better way?

Is it possible for the circuit to automatically reset the 60 minute timer after each interrupted event and power down after 60 minutes of inactivity?

Thanks,
Jeff in Florida

I would suggest a PIC would be the way to go, a small 8 pin one would be all you would need, and would give fairly accurate timings - 555's aren't really very good for any long time delays.

Sebi · 3rd May 2004, 05:34 AM

If You not familiar with PIC, possible solution a counter with 4060. The opto receiver can make a reset by event, without reset the counter run about 60sec, and give PWR off (like a watchdog).

2nd May 2004, 12:25 PM	(permalink)
Uman New Member	Circuit auto OFF feature after no events design A hand held circuit detects the presents of an object using an IR emiter and transistor detector. The circuit is powered by a 9v battery and sounds a buzzer when the IR light beam is interrupted. I would like to add a feature to auto OFF the circuit when no objects interupt the IR beam within 60 minutes, to conserve batteries. The power switch will be cycled to activate the circuit again. I suspect a 555 timer circuit embedded in the above circuit is the solution. Is the 555 timer the way to go or is there a better way? Is it possible for the circuit to automatically reset the 60 minute timer after each interrupted event and power down after 60 minutes of inactivity? Thanks, Jeff in Florida

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3rd May 2004, 05:34 AM	(permalink)
Sebi Experienced Member	If You not familiar with PIC, possible solution a counter with 4060. The opto receiver can make a reset by event, without reset the counter run about 60sec, and give PWR off (like a watchdog).