Hello~~~It's me again.
My sensor project is done actually. However, I wanna use only one DC adaptor to power all 3 of my devices instead of using 3 different ones. The following are the power requirements of them:

Microcontroller: 12V, 500mA
Pad: 9V 100mA
Receiver: 9V 100mA

BTW, I also want to hook up a rechargeable backup battery to the microcontroller so it could still work for 12hrs even if power is cut out. How can I do that? Is this battery good enough?

LiFePO4 Li-Ion Module: 12V 1350 mAh (4x18650 4S Flat, 4A rate)

Thanks...

 

You could use a voltage regulator for the 9V circuits so they could run off the same power supply as the 12V