A while ago, I decided to wire up a Raspberry Pi (Zero W) to a few peripherals, but it stopped working shortly afterward (not entirely, but I think it was undervolting the power rails). I had connected a Relay Module, a PIR Module, and a DHT22 Shield. The Relay and DHT22 were on the 3.3v pins, and the PIR was connected to the 5v rail. DHT22 data was connected to pin 7, PIR to to pin 12, and Relay to pin 13.
All was working fine until the PIR started misbehaving in a way that is consistent with being undervolted (I don't have a functional multimeter atm to confirm, but various results searching for "False alarms at exactly 2 minutes" gave a similar answer).
I had connected them all directly to the pi (no pull-up or down resistors), based on some information I had gleaned from searching. I opted for the DHT22 Shield as it seemed to have an integrated resistor into it (and worked better with the form factor I was going for).
So, I assume this was wrong due to the outcome, so can anyone give any recommendations on what I should add to the circuits so when I do this to a new pi, I don't see the same results?
Additionally, I am thinking about adding another component, which would require sharing of some of the power pins. Is that something that is not recommended, or special steps that need taking? Based on the amperage of the components I intend to run in parallel, everything seems like it should work, but I would like to double check before possibly damaging another pi.