Reversing Camera Into Android Head Unit

I kind of got used to the reversing camera on our "proper" car so had a look into a way of mounting one on the Copen. As we already have a double-din Android stereo installed which has a camera input, the hard bit was choosing where to mount the camera then cable it back to the dashboard.

The second part of that proved easier than expected, mainly due to the excellent description of how to remove internal panelling provided by Rex here: My New Double Din Stereo

As I didn't want to drill any holes into the rear bumper panel, the choice of cameras and locations was fairly limited. However, in the course of my research, I discovered that the later model Copen's rear number plate light is very similar to that on the 2002-2012 Toyota Rav4. That took me down a rabbit hole on Amazon where i eventually found a combined number plate light \ reversing camera for that model which I ordered. (https://smile.amazon.co.uk/dp/B0827XNMW3?psc=1&ref=ppx_pop_dt_b_asin_image).

Just as an aside, there are plenty of RAV4 number plate light cameras on Amazon, eBay and AliExpress. Some have different sockets for the lamp fitting so, if you're interested in doing this mod, check the fitting that you have against the one you want to buy first. Popping out the number plate light is really easy and I really recommend doing a physical check prior to purchase.

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When it arrived, it was apparent that the bulb fitting was ever so slightly different to the Copen's bulb holder. Five minutes with a Dremel and file had that fixed. Out with the original number plate light, in with the new and it was a perfect fit.

Figure 1. Bulb Fitting Fixture Comparison (Camera Version Shown On Left)​

Actually cabling it in was slightly problematic but mainly down to my own incompetence. The wiring diagram showed that the reversing light power cable should be green and white, but there were actually two cables going out of the boot grommet with those colours. Finding which was the right one to use as power and camera trigger was made really easy by a tip I picked up on CopenWorld.

Using some crocodile clip cables on my multimeter, I put a narrow sewing pin in the jaws of the +ve clip with the -ve attached to a convenient earthing bolt. With the ignition on and the car in reverse (obviously not with the engine running), I pressed the pin though the insulation of each cable. One showed 0v, the other 12v. As a further check, with the car in neutral, both showed 0v.

With everything switched off again, I ran the cable from the camera through the existing electrical cable grommet and hooked it up to the camera image feed cable. It was then a case of tying the camera power and trigger feeds together with a Scotchlock connector then connecting that to the previously identified reversing light power cable, again using a Scotchlock. Ground from the camera was connected to the main earthing point in the boot, just above the cable grommet.

Figure 2. Camera Signal Cable Entry Into Boot and Earthing Cable
(Camera feed is thicker black cable coming through grommet, trigger\power is red cable into Scotchlock)​

This was where the problem became evident. Even though the cabling matched the diagram provided with the camera, no signal was coming through to the Android head unit. To cut a long story short, the Scotchlock connectors were too big for the cables they were clipped to and weren't making a circuit. A quick trip to Halfords for some smaller connectors, and five minutes later the image was coming through perfectly.

The head unit has a number of built-in settings that can be applied to the image, e.g. parking guidelines, which I'm still tweaking but overall, it's a huge success. My only concern is that an over-zealous MOT tester may complain about the camera slightly obscuring the number plate (it's still perfectly readable) so I may swap back to the original light fitting, just for the MOT. That's a 10 minute job so it's no big deal.

Figure 3. Final Fitting​

Figure 4. Reversing Camera Image​

 

Just spotted your comment Shahram. Hopefully not too late.

It's a cabled camera but running the cable through wasn't a big deal. The various panels popped off without too many issues.

The power for the camera comes from the reversing light circuit and the image is presented via the head unit. A trigger wire runs from the camera connector in the boot to the HU alongside the camera feed cable which automatically launches the camera app when reverse is engaged. This cable and its connector were part of the camera install kit