Raspberry Pi Forums

Hi!
I'm controlling a led using raspberry pi from a relay board. It is interfaced with a photo sensor program wherein the led has to light up when it is dark and vice versa. But when i'm connecting with the relay and giving suppose GPIO.LOW , it's doing the opposite i.e the led is lighting up. Why?

PS: GPIO.LOW and GPIO.HIGH are working fine when i'm just controlling the led using Pi alone.
please help

Which relay board are you using?

Many of them invert the GPIO signal so need a logic Low to close the relay.

probably your relay is active low.

Probably the relay is permanently connected to +ve at one end of the coil and requires a low at the other in order for current to flow.....

Oh. Yes, i guess the board indeed is active low. It didn't strike me.
Thanks a lot!