2xAA powered PIR
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Took me a while to make it though the idea is very simple. I took this jModule https://www.openhardware.io/view/20/jModule and a BMP280 i2c board (I have a few spare ones) and hooked them up Mini Pro (modified for the battery use) as well as the PIR and the battery compartment. I have to admit I am cheating here - I am using 2xAA Ni-Zn and they are 1.6V each giving me a stable voltage 3-3.2V throughout its life.
I had to do a little modification to the PIR to be able to work at 3.3v. It does work really well. Cannot say much about the battery life as it depends. Sleeping current is low, but the life really depends on how many times the PIR is going to be triggered.Some photos at the end:
And the final product is ...(compared with DHT22)
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