4K cameras with face recognition on a motorhome — without a single hole in the bodywork

No drilling into the outer skin. That was the only condition I set myself when I started working out how to keep an eye on the Phoenix. Everything else then had to fit around it.

On a motorhome it is not as simple as on a house

At home I would be done in half an hour. A wall, two holes, plugs, finished. On a motorhome several things come together at once.

The camera has to look where I need it to, not at the neighbour's caravan. It should not be obvious at first glance, because I do not want the vehicle to look like a guarded facility on wheels. It must not get in the way when washing. And above all, it must not leave a hole behind.

The skin flexes while driving, freezes and expands, so every hole is a place where sooner or later you end up dealing with sealing. When water starts getting in somewhere, it does not announce itself. You find out from whatever swells up underneath two years later. That is why I had the condition before I even started looking at mounts.

What it is made of

The cameras are eufyCam 3C, they record to a eufy HomeBase 3 base station, and the whole thing is kept connected by a Teltonika RUTX50 router. I have had that in the vehicle for a while now because of internet, and it does not have one line but three: Starlink, 5G from T-Mobile and 5G from Vodafone. It switches between them by itself.

The base station can tell familiar faces from strangers on its own. It sends nothing to the cloud for that, the video stays in the vehicle. That matters to me more than the feature itself.

Those three lines in the router turned out to matter more for the cameras than I expected. When one drops out, another takes over and most of the time I do not even notice. A camera with no signal is useless — and that is exactly the moment you would need it.

Everything runs off 12 volts

The router and the base station both hang off the vehicle's 12 V system. So I do not have to switch on the 230 V inverter just for the cameras, which is good — it would have to run non-stop and would draw current even doing nothing.

The cameras themselves do not run off the vehicle at all, they have their own battery. That, incidentally, is exactly why nothing had to be drilled. If they needed power from the vehicle, a cable would have to run to them and it would have to get outside somehow. As it is, all that is outside is a housing stuck to the surface, nothing else.

Nylon housings, SLS printed

The housing here does more than just protect. It is also the part the whole mount is built on. The bracket grows straight out of it, it is not a box slipped over something ready-made.

It did not start from scratch. Somebody had already drawn a housing for the eufyCam 3C S300 and offers it for download; a friend found it through the 3D model search engine yeggi.com. His work was to add the mounting features — the GoPro interface and a seat for the screw. They were printed for me by my friend's company SLS.market, which does industrial SLS printing in PA 12 including blasted finishing. I fitted them myself. First a test piece came out in black PLA, which confirmed everything fitted, and only then were the white ones printed for real.

The material is nylon PA 12, printed by SLS: a laser sinters powder layer by layer. That makes the part isotropic — equally strong in every direction, with none of the weak spots between layers where filament printing could eventually crack from vibration fatigue. For something holding a camera outside a moving vehicle, that is what decided it. PLA would not survive a single season outdoors.

One thing I need to put straight, because I had it wrong at first. White PA 12 with no surface treatment can change shade outdoors, and the rough SLS finish holds road grime far more readily than smooth paint does. How a particular powder fares in the sun is a question only its datasheet answers — it is not a blanket property of PA 12, because it depends on the dye and the stabilisation. So I am planning to give the housings a proper exterior coating in time: degrease, key the surface, a plastics primer and a UV-stable topcoat. The load-bearing job stays with the mechanics, though, not with the paint.

The base housing is neither my work nor my friend's, and it is a paid model, so I cannot pass it on. Anyone who wants it will find it through yeggi.com under „EufyCam 3C S300 Waterproof Cover“. The mounting features were drawn to fit my vehicle and they are not files I would hand out. I am writing here about how I solved it, not a guide to printing it.

Three joints, each doing something different

The whole mount is three joints. If one had to do all of it, it would end up half-hearted in all three respects.

The camera sits in the housing and is held there by a screw with a quarter-inch tripod thread, the same one every camera has. It is printed too, not metal, and that is deliberate. It carries nothing, the camera sits in the housing on its own. The screw only stops it falling out. A metal one would wear through the plastic over time.

On top of the housing there is a GoPro mount with a swivel joint. The angle gets set once, tightened, and that is that.

What holds it on the vehicle

The GoPro mount base is bonded to the degreased paint with 3M VHB 5952F double-sided tape. No screw, no hole.

VHB is not the double-sided tape from the hardware shop. It is a millimetre of acrylic foam and 3M itself offers it as a replacement for rivets and screws. It conforms to unevenness and holds on paint too. In cars it is used to bond trim and spoilers, so the side of a motorhome is nothing unusual for it.

Numbers from the technical data sheet, so that this is not just an impression:

The most useful line is the static load. Roughly 57 cm² of tape per kilogram, so a bit more than a postcard. The camera weighs a few dozen grams, so the margin is decent. For anything heavier you would have to do the sums.

This strikes me as more important than the catalogue strength. On an area of 3.23 cm² the 5952 holds around a kilogram in static shear at 23 °C. At 66 °C only half a kilo and at 93 °C a quarter. A wall baking in summer therefore takes away from it, however well the joint is made. A white skin heats up less than a dark one, but you should work with the worse figure.

With bonding the substrate matters as much as the tape. 3M wants isopropyl alcohol with water at 70:30, and a degreaser first on greasier spots. Then patience: after twenty minutes the joint has half its strength, after a day ninety per cent, and full strength only after three days. Sticking it on and heading straight for the motorway is a bad idea.

I take the side cameras off before driving

I do not want to bury this among the specifications: the side cameras are not on the vehicle while driving. I take them off before setting out and carry them inside.

That is why the swivel joint matters so much. If I had to hunt for the angle again every time I put a camera back, I would stop doing it after the second trip and find a reason why it is fine as it is. As it is, it takes a few seconds and the camera goes back exactly where it was.

The only one that stays on permanently is the rear camera. That is the only one that travels, so with that one I do not rely on the adhesive alone. It is also secured with a 2 mm cable. If the joint let go, the camera would stay hanging on the vehicle instead of ending up on the road behind me.

It is there for what you cannot plan for. A branch, a lump of ice off a lorry roof, or a mistake I made while bonding and do not know about. It costs a few crowns and turns a potential disaster into an inconvenience.

That it holds applies to this housing, this joint, this paint and this vehicle. It is not a certified installation and 3M itself states that this is an industrial tape not tested for all automotive uses. That is why I take the side cameras off and secure the rear one with a cable. Leaving something hanging over the road on adhesive alone does not strike me as a good idea. Anyone wanting to copy this should work out their own area, their own paint and the weight of their own camera.

How it looks

The cameras are high up on the side, by the entrance and the windows. From that height they see along the whole wall and onto the door, which is exactly what I wanted.

What pleases me most is that it does not show. From a distance nobody connects a white housing on a white skin with security, and the vehicle does not look like a guarded facility.

It is not a kit and was never meant to be one. It came about for one particular vehicle, one camera model and one condition. On another vehicle it would turn out differently.

Conclusion

It does not work thanks to one camera or one bracket. It works because a few things fit together, none of which is remarkable on its own: cameras with their own battery, a base station that records by itself, a router with three lines, a housing from a material that survives outdoors, and a mount that can be taken apart at any time.

First I decided what I did not want to do to the vehicle. Only then did it become clear what it should look like.

A camera on a vehicle does not only film the vehicle. Before fitting one, look into what rules apply in your country to filming public space and to recording people, especially when face recognition is involved. It differs from country to country and I am not covering it here.

And one more thing. A security camera is not a reversing camera and does not replace one, it watches a parked vehicle. Nor is it protection against everything. It is one layer of several and on its own it deters nobody.