what's the best way to power an Arduino Pro Mini 3.3V with batteries connected to nrf24l01 + DHT22? 2xAAA or 18650
Thanks in advance, may be my question is a bit stupid but I'm new on electronics
Fernando
Min voltage for DHT22 is 3V, so you will need step up regulator when battery voltage drops. If you have low power sensor in mind it's better use suitable temperature/humidity sensor like HTU21D or SHT21. I've created custom sensor boards with this sensor and it can easily operate couple of years on 2 AA batteries.
Two things helped. I didn't use a regulator and I uses Narcoleptic sleep function to put it to sleep most of the time.
A fully charged 18650 is about 4.2Vdc so I added a diode drop for the nrf24L01 but the other devices can handle it. It my latest version I'm using a DHT22 which I think is good to 3Vdc but basically I run them until they stop transmitting.
I'm hoping to connect these up to EasyIOT server when I figure out all this stuff.