Detecting if my car is parked in the "right" spot

Hi all,

So I have this garage which narrowly fits a car. The garage has an additional challenge: behind the car there is a (wide) door that needs to be opened regularly (see drawing). If the car is parked too close to this door (on the left), we can’t enter that space. If the car is parked too much to the right, we can’t close the garagedoor.

Additional challenge: multiple cars park in this area, each with their separate dimensions.

The best results are when each driver tries to park as close to the garagedoor as possible, leaving the most space for that other door as possible (with a bigger car, it will be still somewhat narrow, but ok).

I’ve found some interesting tutorials online (such as this one A New Parking Assistant using ESP8266 and WS2812b LEDs - YouTube), but they don’t fully cover my needs.

A Lidar module can not be mounted as shown in the video, because it would need to be placed on the inside of the garagedoor (and that door would need to be closed).

I was more looking for a ceiling mounted solution, that can detect a car below. It’s okay if it is a binary sensor (car below - no car below). If I can mount that sensor 10cm inwards from that garagedoor, I think it should work.

Any ideas on this approach? And if it is sensible, any guidance on hardware components?

Thanks!

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Hang a tennis ball from the roof, so the windscreen just touches it when the car is in the right place.

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The picture really helps with understanding your constraints. Nice one.

I’m wondering if a dumbish solution might work here.

Could each car have a predetermined spot for something like this to point at? Could be unmarked on the bonnet or perhaps you could attach a very subtle sticker etc? Different for each car.

Just found this amazing item on AliExpress. Check it out! AU$9.43 40%OFF | Garage Assist Parking Guide 360-degree Adjustable Induction Light Beams Type Parking Aid Double Head Guide For Car Suv US Plug
https://a.aliexpress.com/_mLBkyiy

The cars have different dimensions…

Yeah I missed that!

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Good find, I bought 2.

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How about using one of these on the ceiling just in front of the wall?
https://www.aliexpress.com/item/4000529415321.html?pdp_npi=2%40dis!AUD!AU%246.50!AU%246.18!!!!!%402103243416874806361044759e57c1!10000002692441665!btf&_t=pvid:033bf465-c016-45b9-8e89-17e78f135d47&afTraceInfo=4000529415321__pc__pcBridgePPC__xxxxxx__1687480636&spm=a2g0o.ppclist.product.mainProduct

Personally I can’t really see that working due to their “Field of view” maybe the can be “Blinkered” with a tube to provide a linear beam type path, but I am doubtful…

I have a couple of these. Works fine if the same car always parks in the same space.

or:

or:
https://www.aliexpress.com/item/1005004904162083.html?pdp_npi=2%40dis!AUD!AU%241.33!AU%240.88!!!!!%402103011716874841769382554e4f7f!12000030966548413!btf&_t=pvid:1c74f068-527e-43f7-9202-9fe89bef6a73&afTraceInfo=1005004904162083__pc__pcBridgePPC__xxxxxx__1687484177&spm=a2g0o.ppclist.product.mainProduct

which apparently has a narrower beam angle.

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Thanks everyone for the numerous and useful replies!

The tennis ball option wouldn’t work. Since I need to measure/track distance on the side where the garage door is (right part of the picture) and the car would need to drive trough the tennis ball first.

I have considered the option with the light beam (on the bonnet), but:

  • Since different cars would park there, it would work well for every car;
  • If we would reverse park in this spot, the light beam would be impossible to see;

Hanging a TOF (TOF10120) sensor on the ceiling would be an option. But the ceiling is 300cm high, and the sensor only seems to measure a max distance of 180cm. That should not be a problem as long as the car is higher than 120cm (47inches). But I’m afraid measurements would also become less accurate (and the far end of the bonnet of a non-SUV might be below 120cm).

The ultrasonic sensor seems to be the better fit. It can measure up to 400cm, which is plenty enough. I’ll have to research the beam angle a bit (it should be narrow, given the situation I think).

Thanks a lot. Additional ideas welcome!

I don’t think the cone angle will be narrow enough, but keen to hear your findings…

Another option, depending on the shape of the cars is to use a beam across the doorway from one side wall to the other. You can mount the transmitter and reflector at an appropriate height to be broken by the rearmost part of the car. The problem is that this point needs to be the same / close enough on each car. If there is a slight difference you can run the beam at a slight diagonal upwards but you won’t have a huge amount to play with.

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That’s also an interesting idea. The garage door is about 10 meters wide. Did you have a specific transmitter/reflector in mind that could be used?

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Yeah this sounds good.

Something along these lines? Maybe there are off the shelf versions too?

This was just a super cheap one I saw in a quick search.

needs power to both sides:
https://www.aliexpress.com/item/1005005080926768.html?spm=a2g0o.productlist.main.31.2ee0aa93c5xWEd&algo_pvid=2c06ca0f-4903-410b-8420-912aeb6ea606&aem_p4p_detail=202306222352253566360438260290010670047&algo_exp_id=2c06ca0f-4903-410b-8420-912aeb6ea606-15&pdp_npi=3%40dis!AUD!13.8!8.96!!!!!%402102196716875031453697487d077d!12000031568486428!sea!AU!0&curPageLogUid=j1uuXADy8UiS&search_p4p_id=202306222352253566360438260290010670047_16

Reflector style:
https://www.aliexpress.com/item/1005003728268171.html?spm=a2g0o.productlist.main.49.2ee0aa9390JCca&algo_pvid=df12b119-a2fd-4d3a-b986-bd85b15d2966&aem_p4p_detail=2023062223541513539416214837960010505228&algo_exp_id=df12b119-a2fd-4d3a-b986-bd85b15d2966-24&pdp_npi=3%40dis!AUD!75.87!37.93!!!!!%40211bf49716875032558107688d07c1!12000026953986621!sea!AU!0&curPageLogUid=aqKmmefq4d0j&search_p4p_id=2023062223541513539416214837960010505228_25

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This was the first thing that came to mind for me as well!
Alternatively you could mount it vertically as well, separately for each car. the reflectors are generally very flat or could even be a sticker, so that should work on the floor. Maybe it would just need cleaning every once in a while.

They are called retroreflective sensors btw. Maybe you should consider getting a polarized version, that prevents it from being triggered if a shiny object passes underneath (I reckon a freshly washed car could possibly be reflective enough)

Those break sensors with reflector panel seem to be fit to do the job!

I’m inclined to go more for an off-the-shelf solution. However, such as the one suggested by @sparkydave (the one with the reflector). It can cover up to 15 meters, so that’s great.

Anyway I can hook it up with an ESP-compatible controller, so I can do some magic with LED lights that need to light up when the IR beam is interrupted?

Ahhh. I get it now.

I’m still thinking low-tech. A line on the floor and a mirror on the ceiling? When you can see the line in the mirror, you’ve backed far enough. But don’t let me spoil the fun of a more technical solution. I like those, too!

Nothing wrong with low-tech, on the contrary. However, each car would need another line. And mirror-placement would not be easy given the higher ceiling (3m).