A mesh of open devices monitoring railway crossings "open-closed" status.
I removed the buttons from the PCB, rewired the switches, and use a Particle Electron to trigger each button via 3G from an Android app.
Visualize car data with a free Blynk account, particle electron and Carloop.
Using an old car keyfob and a Particle Electron, you can remotely lock and unlock your vehicle.
Here is an interesting way of monitoring yours or your kids driving habits by monitoring hard braking/accelerations and tailgating data.
Environmental Monitoring Unit K9 Mobile Sentry is a cellular enabled monitor for my dog's safety while in the vehicle during short stops.