Raspberry Pi Project Advice

[EastAfricaGuy]

You don't necessarily need 2 LEDs, just one. If LED is on then the condition is true, if off the condition is false. But yes different coloured ones is nicer.

I think 'the two LEDs' approach is nice.

Why?

Using a single LED, when you get home and the LED is off... two things involved:
- either there's no car inside the garage
- the system/controller/LED is not working, there's no power, LED is burnt.

So, to guarantee that the system is working, better to have two LEDs.

It is either green or red.

If none of them is ON, then something is wrong.

 

[Ma’bad]

So, I'm not sure if this would work. Could you leave a Bluetooth tracker in your wife's car and use Home Assistant to monitor it?
You could then set up automation to open the garage automatically if you arrive and her car isn't in the garage. Alternatively, you could set it to turn on a smart bulb red if you arrive and her car is in the garage or green if there is no car parked

 

[Koos Custodiet]

So what you do is, you get an IR beam normally used to stop your automatic gate from closing. " i5 Wired infrared Beams" and R500-ish. Make it so the car in the garage breaks the beam. The receiver has a normally open and a normally closed contact. Wire it to an LED outside your garage. Power the whole thing off an old 12V DC brick.

Or mess around with an Arduino, it _is_ more fun.

 

[hilt_ctn]

I just built this out with an ESP32, a Neopixel ring light and an mmWave sensor. <- This is the only sensor I had lying around that measures distance. It should not be used for this application. Instead look to an ultrasonic ( mentioned previously ) or a Time of Flight sensor. The Neopixel comes in individual LED's as well. Again, this was what I had it lying around.

This was just to show it can be done.

 

[Ϲhristopher]

A really cheap option would be to use an IR obstacle avoidamce sensor that simply outputs high/low to determine if there is a car in the garage, probably under R50. You can wire an LED directly to it's output, but you'd be better off adding a relay.