I have a Arduino Pro mini 328 - 5V/16MHz. I currently have six DS18B20 sensors and the communication is made via a HC-05 Bluetooth module.
I am powering it via a basic Alcaline 9V 6LR61 but this battery is too big but the battery life is good.
I would like to know what are the best possibility for having a thinner and rechargeable battery like a Lithium Ion ? The 6LR61 are now too big for me, same for AA(A), it would need to be in a restricted area.
I assume I need to have a battery >= 5V but I only find 3.7V