Some time it is hard to find solution for raspberry pi.

This time we are solving issue : how to Power Down Your Raspberry Pi using GPIO.

Step1:

copy script from power_hold.py

Step2:

sudo apt install python3-gpiozero

#connect button GPIO 21 and GND

#run below command to test

python3 power_hold.py

# hold button(gpio21 and GND) for 2 second . your pi will be shutdown.

If it is ok then power on your pi3 again

Step3:

Now execute your script ,when raspberry pi power on every time.

sudo nano /etc/rc.local

in rc.local file at the end your code must be look like this

python3 /home/pi/power_hold.py &

exit 0     

Thats it now . restart your pi again and test it….