Did you guys know how I can switch off/on the Arduino from a phone using the Bluetooth sensor?
Do you want a complete power down of can the mystery Arduino go into and out of a sleep mode?
to be short in words as you are:
install a bluetooth-serial app on your phone
connect a bluetooth-to-serial-modul to your arduino
send your "switch-off-command" with the blue-tooth-serial-app
code an arduino-program that receives the serial data received by your bluetooth-module
switch a bistable relay which has the arduino-power connected
Though if your arduino's power is switched off you have to press a phsysical button to switch the bistable relay to its other state to switch power on of the arduino.
There is no way to remotely switch the power on again.
Are you sure you want to have it working this way
best regards Stefan
Thank you i got the idea and it working
Are you going to share with us the result so that others may benefit?