Controlling 12v Signal with Proximity Sensor

[PedroC88]

Hello everyone, I'm considering starting my first project and don't know where to start (aside from MySensors of course), I have a 12v circuit which I'd like to interrupt based on proximity, basically I want it to operate normally but interrupt when I come close (I was thinking a bluetooth proximity sensor connected to the phone, but I'm open for any ideas).

I'm installing this on a car so the "switch" needs to run on batteries, I think I could make it work out of the battery of the car but since the device actually runs when the car is off; I'm concerned about the battery drain over an extended period off.

So the questions basically are:

• What is the best approach for this proximity switch?
• What hardware to I need?

[doctor64]

@PedroC88 Sorry, i not completely understand your requirements. Do you want a sensor which generate signal when somebody walk near the car? You can look at PIR sensors, but i am not sure can they work outside a building.

[PedroC88]

@doctor64 said:

PIR sensors

Not anyone, a sensor that generates a signal when I come close to the car, I rather it not be IR since, AFAIK, they need to be in specific positions to work, unlike NFC or Bluetooth that cover areas around the sensor.

Basically I'm trying to create a smart switch that goes on or of based on whether I'm close (in the range of 10-20 feet) to it or not.