I’ve rigged up a remote car starter that integrates with HA. It’s pretty crude, but it works really well. I started with a Sonoff and a spare remote for my aftermarket remote starter. I started by cutting the trace that runs from the Mains terminal to the relay just before the relay and carved out a spark gap. This allows the Sonoff to still be powered from wall power and keeps the relay isolated. Then did the same thing for the neutral trace. I soldered a jumper from the neutral trace to the old mains leg of the relay to create a switch at the output terminal of the Sonoff. The remote only requres that you hold the button for 3 seconds to trigger the starter. That makes it really easy to rig up the switch. I cracked open the remote and soldered a couple of leads to the button and landed them in the output terminal of the Sonoff. I have Tasmota installed on the Sonoff and have it set up as an MQTT switch in HA. I setup an automation that triggers 15 minutes before I normally leave for work conditioned with the workday sensor, temperature <40 degrees and my day off calendar state = off when it fires it turns on the relay, delays for 4 seconds and turns off it also sends a TTS message to a chromecast speaker that annouces that the car is being warmed up. Like I said it’s crude, but it totally works. Now I’m excited for some cold days to see the magic unfold.

