Options for a reversing camera

[moltuae]

Originally Posted by HPsauce

I'd be interested to know what you were thinking, given that the button on the RNS-D cycles through the available inputs I thought that might make it very difficult.

It might not be that difficult. Cycling would be possible, using a programmable device or maybe a simple counting circuit to generate the button activation pulses but I think a simpler approach might be to identify the video switching circuit and bypass it, especially if it turns out to be a regular composite video signal. The hardest part will be finding where the video switching takes place, then it's just a matter of intercepting it and inserting a second two-way video switch after the first. Of course this would all be much easier with a schematic diagram ..... I don't suppose anyone has one for an RNS-D?

It's possible also that the video switching takes place in the boot (haven't looked but the RNS-D head unit pinouts might give some clues). If that is the case, there may be a single composite video signal going to the head unit that you could intercept.

[HPsauce]

Originally Posted by moltuae

It's possible also that the video switching takes place in the boot

Don't think so. Remember I don't have a TV tuner, just a video input lead/adapter plugged into the 10-pin DIN-style socket on the RNS-D.
It works fine, when plugged in (even without any video signal) it is detected and the RNS-D will cycle through it, when missing it just offers Radio and CD.

According to various comments I've read online it's a pretty standard video connection and just needs one specific pin to be at +12V for the RNS-D to recognise it exists.
The attached picture is actually from a unit made for Ford by Blaupunkt but I'm pretty sure it's the same.

[moltuae]

Originally Posted by HPsauce

Don't think so. Remember I don't have a TV tuner, just a video input lead/adapter plugged into the DSIN-style socket on the RNS-D.

Ah, yes. Must be all done in the head unit in that case. I remember I modified the analogue tuner unit on mine to add a some RCA connections and I seem to remember there was some video switching capability built into that unit to switch between the tuner and an external source, but you would still need to select the tuner source on the RNS-D of course.

It's possible in that case that the composite video is digitised before switching between it and the various menu displays, which would make overriding that more difficult (particularly without a schematic). In which case a circuit to simulate the required button presses might be the simpler option. Ideally the circuit should have some feedback to 'know' when the analogue video input has been selected. From memory, I think the tuner only powers-up when the TV input is selected, so it might be possible to detect something to use as feedback there.







Edit: The pinout you've posted suggests component (RGB) inputs. Also there appears to be a 'Vid-ON' control connection ..... is that an input or an output to control the tuner I wonder?

[HPsauce]

Yes, I think the box I have converts composite video to RGB and I also think the Vid-on control is the one I referred to above which just lets the RNS-D know it's there so that it appears in the list of options.

[HPsauce]

Minor progress, of sorts today, on the back of another issue, caused by an incompetent garage.
(There will be a short angry thread on this later, re removing/repairing numberplate light fittings - http://forum.a8parts.co.uk/showthread.php?t=11923 )

Anyway, the upshot of this "issue" was that I had to pretty much totally dismantle the boot lid including the liner AND the numberplate mounting plate.
Doing so I did find some useful information to help me execute my plan:

1. The numberplate mounting plate is only held on by 5 short self-tapping screws (from behind into its plastic), plus the two long metal screws (optional if adhesive pads are used) through the numberplate itself.

2. One of these, at least in my case, is partly obscured by a large component of the boot locking mechanism, but I just managed to undo/redo it without taking that off.

3. The spare plate I bought is EXACTLY the same colour (though many years older) than the one on my car. Examined in all lighting conditions including full sun. Though on the spare the central (of 5) screw fixings is hollowed out and ineffective.

4. Importantly there are no spare holes in the boot lid behind the plate, just those for the screw fixings and two numberplate lights. So a new hole will need to be drilled for the camera lead.

5. You can take the plate off (and replace) with the lights in situ. So I might drill the hole and run the cabling, leaving the connectors ready at the hole behind the plate. That way I can easily take the plate off and swap it for the spare with the camera pre-mounted and join the leads - it has about a 50cm fly lead for power and video and there's a decent void for the cabling.

6. You need the boot liner off to take the plate off, but I expected that and need to do that to run wiring. Done it many times.

7. Finally, I can't see any way of incorporating the camera in either of the light units so it will be separate from them.

I don't have time to fit the camera today so I'm off to reassemble my boot lid now.

[HPsauce]

Another bit of mental gymnastics that might help anyone else thinking of doing something similar, i.e. fitting the camera above the number plate.

The plastic backing plate, as noted above, is fixed with a few screws and the numberplate lights are fitted separately (and tightly) directly to the metal boot lid, presumably to keep them watertight. The plate itself is not sealed around the edge (though someone here has done that) so water can, and will, find it's way behind it.
Even if sealed all round the edge sprayed water can enter around the numberplate lights, there's a significant gap there.
There are small sealing discs around each fixing screw location because of that. I suspect degradation of those (mainly the larger two for the two big numberplate screws) is probably to blame for the water I get inside the boot lid, so I'll renew all those when I do this job properly.

So, I'm going to mount the camera on the plastic backing plate, ensuring it is as waterproof as possible - the cable entry isn't clever so I'll seal that. But if there's a hole for the cable I won't worry much, though I may put a grommet on it.
But beyond that I'll concentrate on providing a new waterproof entry (grommets, sealer etc.) for the cable through the metal behind it, making sure any connections are behind the seals I use.

[HPsauce]

Originally Posted by HPsauce

So, I'm going to mount the camera on the plastic backing plate, ensuring it is as waterproof as possible

Or maybe not.....

Looking again at how the numberplate lights are fixed directly to the metal structure of the boot lid, I'm very tempted to do the same with the camera.
It will make sealing against water ingress easier, and adjusting the position precisely for the best view. Wiring will be simpler too.
Finally, a hole will need cutting in the plastic numberplate mount so that it fits over the camera, but that will be easy enough.