I have a small circuit where I need to control two relays using an UNO in sequence. This is a very intermittent operation and operated on battery. If it was only the UNO, I could have resorted to a bare bone Atmega328P and followed the Power saving tips outlined by Nick Gammon. http://www.gammon.com.au/power
But in this case the relay board also is battery powered and so at the end of the operation ( 5 sec maximum ) I need to shut down the whole stuff.
Refer the attached circuit which I tried and it " kind off works" But of course I am not happy with it as the Pin 3 is powered even when the UNO is off. Blocking diode did not work. This is a P-Channel MOSFET which needs the Gate to be pulled low to fire. Would a N-Channel MOSFET be OK instead ?
Anyone try anything like this ? Would be glad to get some tips !!