Sometimes the car is left unlocked - attention is normally on the two babies - so I’m looking for a way to get a notification when this happens.
I don’t want to hack the car, so I figured detecting the key fob being pressed was the way to go.
Something like this:
Place my custom device - D1 mini, and RF receiver - near my parking space
Detect when car is UNLOCKED
Detect if me or my wife leave the house (presence detection by checking phone/WiFi connection?)
When that person returns (or if nobody left at all) wait 15 minutes for a LOCK signal
If no LOCK signal is detected then send an alert
The difficulty so far is that I can’t find any info on sniffing the RF transmission from the car key fob.
AFAICT, the fob sends a message to the car consisting of an identifier (to make sure the key fob is the right one for the car), an instruction (which button was pressed), and a rolling code (as a security measure). I don’t want anything to do with the rolling codes! I just want to make sure it is my key that is pressed, and know which button.
I’ve seen posts in the arduino forums about similar things with garage door openers, and most point to using a library called rc-switch but I think these rely on knowing the chip in the remote - googling the chips inside my car key return zero results.
I get that car thieves don’t need any help! But like I said, I’m only interested in detecting if my legit remote has been pressed.
Ah, OK. As a German Car Specialist I cannot help on that one…sorry
If the car is parked at home and within range of a zigbee and or z-wave network, my thought process would be to hard wire in a simple contact type sensor across one of the lock circuits in the vehicle, but my knowledge on French cars is pretty slim I am afraid.
You donot want to hack the car: logically as then guarantee might fail
You also have a detection issue when not home, i.e.the car needs to be in range of the HA network
As you already mention, the only thing is to sniff if your key sends a ‘close’ signal… which of course is no guarantee at all that the car is actually closed…as you have the ‘which button was pressed’ then you could theoretically use that. My rfxcom detects my VW key but honestly I have not done anything with that.
However, on a different note… if people want to break into your car then they will, closed or not…and in that case it might even be more beneficial ti have the car open (!)…less damage…speaking of experiences(mutliple)
I have found the Michael Ossmann talk (video, code) about clock recovery really interesting, but I have zero experience in DSP, so I am just hoping it will work in my use case - not having the datasheet for the transmitter chip!
I think I’ll need to add some C++ code to demodulate the signal (as in the above), then add some logic (C++ or HA YML?) to check if the received data is for my key, and which button was pressed.
Is ESPHome the right tool to use for this?
