Arduino Pro Mini with Arduino GSM shield - Power reduction.

Dear Community

Im trying to build a device for long term logging of data, storage on microSD card and once in a while, it should send an SMS with data. So far i have succes combining Arduino Pro mini and the GSM shield (M10). But this is only possible because i power the GSM shield externally.

My challenge is related to reduction of power consumption by the GSM shield. My succes criteria is to get below and avarage power consumption of about 3 mA. The pro shield itself i can find many post on the net giving good advice, especially the LowPower library by Rocket Scream is nice and easy to apply.

However, reducing the power consumption of the GSM shield i find difficult. I can not supply the GSM shield directly from the Arduino pro which has a maximum output of 150 mA - that why i use the external power. But as i only expect to send data about once per hour, i thought about controlling the external power via a relay. I found the Omron g6e 134p only draws about 40mA of current so can i use this to turn on the gsm shield 1-2 min every hour to send data, and then turn it of againg? this would save me a lot of power, but if anly of you have better ideas for this it would be much helpfull to me.

Thanks for the many helpfull questions and answers in this forum :wink:

Maybe your modem could have a software sleep mode that you can turn on and then it enter in sleep.
Anyway if yiu decide to cute the power to the modem like you said, instead of a relay why not use a transistor or a FET instead.