ATMEGA 328 Bare + DHT22 + radio with 2xaa. Need Step Up and a hint from you

[sineverba]

Hi to all,
realizing a DHT22 sensor with bare ATMEGA328 @8MHZ BOD disabled and the NRF24L01.

I feed them with 2XAA rechargable that feed 2.70V at max charge.

So, radio and Atmega works without issues. DHT22 need at least 3.1volt, otherwise cannot read.

So, I'm buying some step-up / booster voltage. My issue is:

1. With the step up, best to feed only DHT or also the Atmega? (not the radio, of course, 'cause rated at 3.3v)
2. My plan was feed with booster only the DHT22 and use the battery direct to the Atmega and Radio (so I can also monitor them).

Thank you

[mfalkvidd]

@sineverba

1. Only the dht
2. Yes?

[rozpruwacz]

@sineverba you can try even more sophisticated solution, the boost converter with a enable or pass trough pin so you can power the dht only when needed and save more energy.

[sineverba]

@mfalkvidd thank you!

[sineverba]

@rozpruwacz mmmm interesting ..... I could put a NPN on GND of DHT and when I need read activate it.... Do you mean this?

[rozpruwacz]

well yes, that will do the same, but i think that using for example MCP1640C (you can check the example project here https://www.openhardware.io/view/279/Adjustable-Boost-Converter-with-Pass-Through) will result in simpler schematic :)