Raspberry pi serial adaptor from Facelesstech:
If you spend a lot of time building things with a raspberry pi you will eventually run into the problem that you have booted your pi it’s not plugged into a tv/monitor and it’s not connected to wifi. You don’t want to just turn it off because it could corrupt the sd card so what do you do. I recently ran into this problem but luckily I had a serial adaptor on hand to hook up and tell my pi to turn off.
Check out the video after the break.