I'm using a Pro-Micro to send messages using NRF24 module from a remote location, using batteries (later on, will be recharged using solar panel).
To conserve power, Pro-Micro wakes up every 30 minutes, sends its data. My goal is to power up NRF24 module only when needed, in order to conserve power as much as possible.
For that I tried 3 ways:
Using a Relay to cut off
5Vinput to the NRF24 module.
Using a MOSFET
FQP30N06, connected to
GNDof NRF24 module.
powerDown()function reduce consumption.
These are the current draw results:
a) During sleep, power consumption of Pro-Micro only is 3.4 mA ( due to LED remains ON ).
b) Pro-Micro + NRF24 module, both normal operation ~70mA.
c) Using a relay + entering Pro-Micro to Sleep mode: 6mA.
powerDown() + entering Pro-Micro to Sleep mode: 30mA.
e) Using a MOSFET + entering Pro-Micro to Sleep mode: 180mA. (yes, MOSFET turns off power to NRF24 ).
** I have to say that my first go was for using a MOSFET, but I was amazed by the result! What is the reason for that? Can it be the when MOSFET in its OFF state consumes so much power ?
** I would like to hear from other's experience for better ways to do such.