timed light circuit
timed light circuit
(OP)
I want to make as simple a circuit as possible, but can't figure this one out (I'm a ChE, so go easy on me).
I want a circuit with 2 LED's - one red and one green. A clock will turn off the green and turn on the red every 12 hours (at 5 am and 5 pm). If someone pushes a button at any point, the lights will switch, red off, green on, until the next 5 o'clock rolls around. ie: if someone presses the button at 6:00, the green light will be on for 11 hours, but if someone presses it at 4:45, it will only be on for 15 minutes.
I have a 12V DC source.
Any suggestions?
I want a circuit with 2 LED's - one red and one green. A clock will turn off the green and turn on the red every 12 hours (at 5 am and 5 pm). If someone pushes a button at any point, the lights will switch, red off, green on, until the next 5 o'clock rolls around. ie: if someone presses the button at 6:00, the green light will be on for 11 hours, but if someone presses it at 4:45, it will only be on for 15 minutes.
I have a 12V DC source.
Any suggestions?





RE: timed light circuit
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RE: timed light circuit
RE: timed light circuit
I'm curious how long this can run before you'll need to reset the timing for 24 hour accuracy.
12V is good for LEDs; red LEDs typically need 1.8V, and green LEDs typicaly need 2.1V, so for 10mA through a red LED you'll want a ((12-1.8)V/0.010A =) 1000 ohm resistor in series with the red LED. The green LED will need a ((12-2.1)/10mA = ) 1K resistor. If your LEDs take more or less power then recalculate the current limiting resistor with the above equations.
John D
RE: timed light circuit
Or just a cron job on one that's already there.
Mike Halloran
Pembroke Pines, FL, USA
RE: timed light circuit
RE: timed light circuit
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