That should work just fine. make sure external light cannot get to the LDR, just the light from the neon lamp.
It may be worth adding a capacitor across R2 so you get a more steady signal.
Are you using a commercial Neon lamp or wiring it yourself? Just remember to be VERY careful around mains!
i will put them as close as possible ^^just one point .... Neon has a very specific spectrum , mostly in the red , is your LDR sensitive to this ?? if the neon and LDR are very close it will probably be OK.
1uF enough ?I've used that set-up. It works very well, using a bog-standard LDR. As Dendad suggetsed, use a capacitor across R2.
To work a uC input the voltage must cross the input thresholds and by selecting the resistor value that should be possible, especially if you make sure all external light is excluded.if i want to connect the output of the circuit to interrupt pin of any micro-controller should i modify the circuit ? or adding the capacitor across R2 enough?
Depends what you want the micro to do in response to a light level change. If R2 is 10k then I'd use 10uF to give a time constant longer than the mains cycle.1uF enough ?
by Jake Hertz
by Jake Hertz
by Duane Benson