Steering wheel buttons, controls and integration of car functions with Arduino

[ERA_Evil]

Hello all, this is my first post.

I am new to the forum but not so new to Arduino. Previous experience was fixing my 3d printer as the original board died, so I switched it over to Arduino, while most of the code is available, I did have to rewrite several parts to make it work with my particular model (Chinese Anet A8 copy).

Anyways, on to my project, I am building street-able racing car, which has an aftermarket steering wheel. I came across a button plate that goes between the steering wheel and the hub, which has 8 programable buttons (NRG WCU-008) and work off a battery from the plate, and send signals to the "brain" wirelessly, but being I don't want to spend 360 on it and that I love tinkering, I would like to go about making my own version but incorporating more than 8 buttons and functions.

So I can make the plate and add buttons which would be 10, essentially have all major functions on the steering wheel (turn signals x2; corner lamps, then headlights, so 2 here; lo beam/hi bean switch x1; horn button x1; 1 accessory and 1 starter button to turn on the car; wiper 2 speeds) Also a rotary switch could also work here, for example on the wiper, instead of 2 or 3 buttons

So my train of thought was around using a mini or nano in the steering wheel, I can either power it with a battery, or try to use the stock horn cable and convert it to provide the power for the board in the steering wheel. I would need this one to wirelessly communicate to a second board, possible an Uno/ATMega. Additionally I would like to control other things, the idea is using a relay board as I see there are some that have 2, 4, 8 or even 16 onboard relays, so as to keep everything protected. The mini or nano from the steering wheel to the main Uno would be one part, but I would also be interested in making an app for android and try to communicate with the Uno to control other functions, say like the locking system, windows, lights or other things about the car.

I would also like to look into working with the Arduino and leds to make a shift light, since the cars signal is a square wave, would be nice to get clocked leds and make it sequential and RGB to change colors, and interested in seeing if any car info can be taken from the ECU and displayed on to am OLED screen or several. ECU is chipped so I have access to the info on my cellphone via app and Bluetooth so I already have the means, just need to be able to access the ECU via the installed Bluetooth and pull the data, and proceed to display it. Sort of like the Chippernut sequential shift light, which was done off of Arduino

My questions are:
What would be better a nano or mini on the steering wheel? I would essentially press a button, which makes the signal go to this board and communicate to the Uno to trigger the relay and make the requested task (turn on/off lights, the engine, wipers etc.)

What would be the best connection type between the involved boards, in case I may expand and incorporate more than 1? Bluetooth, RFID, Wi-Fi, connection distance would be around 1 to 1.5m (3 to 5ft) at the most due to space for the other board with the car.

Would the Uno/ATMega work for this or would there be a better suited board for this project?

This would be the first major project I want to do with Arduino, I know its complicated but nothing is impossible, and am ok with learning and getting in to it to accomplish my goals. Also, where ever I am wrong, or if someone has a better idea on how to go about this task, I would greatly appreciate any feedback. It is a big project with several angles, and more the more brains the better.

[mikb55]

If you are using this for critical safety functions such as lights and indicators then it needs to be super reliable. What happens if the battery gets low or radio interference causes the signal to dropout?

The lights in modern cars are controlled by proprietary control modules and CAN bus messages. Are you planning to disconnect those and use your own switch boxes?

[ERA_Evil]

Hello, thanks for the message. Regarding the car it is a 2000 model Honda, so there is no CAN bus, I think it would definitely be hard get into it, thankfully it does not have that system.
Regarding the battery, well if the battery ran out, pretty much nothing would work, unless you mean that a lower voltage would make the system malfunction. I may be wrong here but wouldn't think so as the car is 12v, and the boards are what 3.7v - 5v? So if it were to drop, car would loose functions before the board not being able to operate.

Regarding the interference, I would definitely say that I am out of my element here, but, I would simply be tapping the Arduino system I want to build onto the cabling itself, its a lot simpler with no CAN bus or anything, simple cables, grounds, fuses and switches, I'm just changing a switch to another, but having them on the steering wheel is a commodity, but I could still retain some switches, I would definitely deem the lights critical, so I could leave the stalk in the steering column as backup to turn them on, should anything happen to the Arduino system. Due to the hub and a deep steering wheel, you can't actually reach the stalks easily, as the driving position is a little further back than normal, and with a 5 point harness it gets even harder as it definitely restricts movement. I know the starter would be critical too, but since it is a manual one can always bump start it.

Since the car is transitioning to be a race car, it will eventually not see the streets, at this point, the car is more of a weekend driver and it goes to the track on it's own, but the more the car progresses to be a track car, there will come a point where it will no longer be streetable. So I am not too worried about that, as I am foreseeing that by the time I finish the Arduino system, the car would probably end up being a track only car

And you do bring a completely valid idea here, which now prompts me to include physical back-up switched in case something happens to the Arduino system, y always have the back up physical switches at the ready, It would definitely not be good to loose a race due to a system malfunction. I suppose I could tap into the board with the 16 integrated relays and activate them directly