Read battery voltage from battery which is powering arduino I have a 5V arduino pro micro. I want to power it with a 3.7V lipo. 


Should I use a step up module to convert it to 5V? 


I also want to measure the voltage of the battery. 


How can I do this? 


Because I read that the power source also the reference voltage is so I cant measure it with an analog pin right?

I also use a lipo charging module to charge the battery.

Thanks for helping!
You can read the Arduino's supply voltage see here How to measure the supply voltage of Arduino without using an analog pin Alternatively use the internal 1.1V reference and a suitable voltage divider to read the lipo's voltage