Maker Pro
Maker Pro

That kind of photodiode to use for HC-SR501 PIR module.

seanspotatobusiness

Sep 11, 2012
193
Joined
Sep 11, 2012
Messages
193
I'm using a "HC-SR501" PIR module to control a lamp I'm making for my hallway. As well as being motion-activated, I want to use a light sensor to only allow activation after dusk. The HC-SR501 comes with this functionality - you just need to add a suitable component at the right place on the circuit board - the problem is what components are suitable?

According to this webpage, a CdS light-dependent resistor would need to be of an uncommon high-resistance type. I have some CdS LDRs but I don't know what their specifications are and connecting them to the proper pads on the PCB had no effect; possibly because I also need to make a bridge to the 1M SMD resistor (I don't understand why the PCB wouldn't already connect these two). The webpage says they used a photodiode and replaced or bridged the 1Mohm resistor with something much lower. If I search eBay for photodiodes, I see a variety of different components and I don't know which I should be trying. Thanks for any direction.
 
Top