hi,

i see that i can add ldr to Hc-sr501 pir sensor so it will work only at night,the output become high for a certain period if any motion detected .
can i modify it so the output become always high at night(even no motion detected) and goes low during the day ?

L

 

hi,
Look at this clip, short out C6.
Note the TX time constant.
Once triggered the sensor output will always be High [On]
E

 

i short the c6 and test the circuit, the output always high (dark or not )
i need the output to be high at night (without any motion ) and off during the day.

L