When things become sentient, it's good to be able to remotely kill power.
I highly recommend building something that scares you every once and a while. In this case, I’m planning to enter an autonomous vehicle into the AVC in 2016, and it's pushing my limits of comfort. A 1,000W motor with a large battery pack behind it means that if things go wrong, they go really wrong!
For that reason, one of the new safety requirements of the AVC rules is a remote kill switch that allows the user to safely and remotely power down the vehicle. So here's a tutorial going into how I built the wireless kill switch based on the RFM69. And to demonstrate this... well... let's start with a margarita.
Checkout the kill switch tutorial for the complete rundown!