The core hardware for the camper control unit consists of an Arduino processor and a TFT touchscreen display and these two items on their own can provide a system that works, albeit with some limitations in what it can control.
The Arduino CPU
The processor I chose originally is the Arduino Mega 2560 r3. In part this was forced on me when I was using a parallel display that used up or covered most of the board’s inputs and outputs. Although you can probably get away with using a smaller Uno board the Mega gives so many options I doubt anyone will run out of input and output pins in a motorhome or camper van !
The source code for this project is all geared towards the Mega 2560 so, unless you are confident in your coding abilities or have a very good reason not to, you should probably stick to the same processor.
The display panel
The TFT panel/touchscreen took a bit of choosing but for a number of reasons (and some false starts with other displays) I eventually settled on the Nextion displays. These have a major advantage over the “passive” displays in that the Nextion display is standalone. You load it with it’s own programme and it takes care of the display and touch handling, communicating with the Arduino via a simple serial link.
As well as reducing the load on the Arduino in controlling the display and interpreting touches/buttons, the main advantage for installation is that the display just need 4 wires to connect it to the Arduino. This means that the touchscreen panel can be mounted anywhere and the controller hidden away in a cupboard. The 2.8 inch version is just about a perfect fit inside the CBE mounting plates I used to mount mine…
Note that the enhanced version has a built in real time clock that can be used instead of an external module to do the same. The battery does make the panel slightly deeper though so bear that in mind for mounting the panel. I use the “normal” panel rather than the enhanced version.
Connecting to the CPU
To make it simpler to hardwire connections to the Arduino I use a breakout shell that makes it easier to solder wires to the Arduino input and output pins. I use the Wingoneer ones below, I use the solder only type but the screw terminal type might be a good option, especially if you’re not confident with soldering !
For a vehicle mounted system, using the simple push on pin connectors is probably not a good idea as, with vibration, they may well come loose.