RFID power shutdown

Hello all,

So have the RFID and Arduino now controlling a 12v power supply. The next stage.. I cant have any electrical drains long term. So the idea is to have a push to make button to power up the arduino then scan the RFID and let go of the button. I need the arduino to stay on when i let go of the button and then when I scan the RFID it shut off all the power.

I cant really think of a way of doing this. Diodes maybe?

Thanks all.

Look at the Arduino power saving and sleep modes (library/tutorial). The Arduino should wake up on a button press, power on the reader, read the RFID, shut down everything, and go to sleep again.

Ive had a look at that but Im still concerned about power drain. its a lithium battery so its a bit temperamental on voltage and it might be left for some time.