Who knows things about cars?

I have a Jeep, and twice since I’ve lived here, it’s been broken into; this got me thinking… How difficult or practical would it be to design a ESP8266 Module to be attached to the alarm signal wire that when connected to the wifi (native on this board) would send an alarm or signal or notification to Hass. Can we do this?! I want lights and sirens and to scare the piss out of whoever dares mess with my things!

if you were running the ESP8266 24/7 you’d just need to step down the voltage to a level the ESP could read (some say 5v is fine but most say 3.3v is safe) and then just check for a pin state to go high. Then just fire an mqtt message or whatever you want to HA.

How long would you say a standard car battery could safely run an ESP for and still be able to crank the engine?

I’m no EE but someone on reddit said this

That’s from a question asking about running it continuously. I’d imagine if you were cranking and running your car daily or every other day you’d probably be fine. But again I’m no EE.

MTA. You could just have it sleep (or off) until it gets ‘powered on’ by the alarm and then send it’s message. That way you wouldn’t even need to keep it on. Of course you’d have to factor in boot up time into the equation. The Wemos boards I use power up rather quickly so as long as it could connect to your wifi it probably would be rather quick. just some food for thought.

That’s pretty close for a ballpark estimate.

Using this data:

And assuming an 85% efficient 12 to 3.3V DC-DC converter, worst case a 50Ah battery would be exhausted from the esp alone in 10 days. Note there will be other standby currents your Jeep consumes, e.g. the alarm system), so in real life less than this.

If you put it into deep sleep and use GPIO interrupts to only wake the device to report an alarm you could get standby times longer than the battery’s service life.

Modem sleep alone would get you something like 3 months.