Hacking a RS- 485 device

Hey everyone! I'm new to the forum, just a quick question.

I have found a Electric wheel chair controller at the Junk yard. Along with the entire base of the wheel chair the motors and battery charger.

From what I have found on YouTube in order to use the factory controller I need the factory joystick that communicates with the controller with RS 485 SharkBus.

How hard could it possibly be to decifer what kind of signals I need to send this controller on the RS 485 network to make it think that my Arduino board is the joystick for it?

Is this kind of stuff usually coded in a way that's non standard?

If you are really sure, that it is a RS485 connection you will need

1) some kind of hardware, so the arduino can communicate via RS485 maybe something like this: RS485 Shield this may be the easy part

2) you need to know the protocol: how the joystick "talks" to the controller this may be the hard part if you do not have much information about the protocol

2) you need to know the protocol: how the joystick "talks" to the controller this may be the hard part if you do not have much information about the protocol

You could try to sniff the communication using a logic analyzer like Saleae or another brand to capture the communication and repeat it in your arduino ...

Is some reference to Shark printed on the parts you managed to salvage that makes you refer to SharkBus?

I had a quick look online and could not find much help in the details of this protocol but a starting point might be to look here if you have not found a better offering. It looks like the signal is differential but the protocol is proprietary so you may have a lot of difficulty working it out.

The main issue is to know baud rate, parity, slave Id, and stop bits of your controller. If you have those things, then connect your controller to modscan software using rs485 to usb cable. There you can see which address have what value and format also.