I was searching for something for my RV and I stumbled on this page. I thought I'd share my project with you.
Everything you're trying to do is doable... Including the snazzy screen.
I have a 1983 American General DJ5L Postal Truck I've built an iPad Control system for using Arduino parts.
The above diagram represents the parts I used and the system components I'm controlling. I have 32 relays in the vehicle. As of now only about 16 are being used. I decided to rewire the vehicle to gain individual control of each component. I wanted to be able to create flash patterns and interesting "scenes" for my vehicle.
Above you can see the prototype. There are 4-8 channel SainSmart relay boards, an Arduino Mega, Ethernet Shield, a USB power supply and lots of wires.
For now, I have a 2000w power inverter (Just something I had) powering a wifi router, the Mega and the relays. I intend to power the system via the vehicles battery and a small solar charger to maintain charge eventually.
Another view of the system components shows the Mega and Eithernet Shield.
The above image is a screenshot of the interface.
This link shows the system in action as it is now.
In the video, you can see how I'm able to control individual components of the vehicle. This gives me the ability to create all kinds of flash patterns and scenes. Towards the end, you can see how I was able to make my blinkers work together with my traffic light bar. The possibilities are really quite endless.
You can see in this image I tow my DJ5L behind my home. When I upgrade the power system I anticipate accessing the DJ5Ls lighting system wirelessly so I don't have to attach tow lights to the vehicle while it's in tow.
Were I to install a GSM chip and pay out the $ for a monthly connection, I could control the vehicles system from anywhere. I'm far too poor for that nonsense.
At the moment I'm living in the mountains with very slow internet, next week I'll post all the resources I used to make this system. (When I say resources, I mean links to source code and information I used freely available on-line. This has been months in the making and I am not available to provide any type of regular help and support to those trying to do the same.)