I have a Futaba RC transmitter and receiver, and an electric wheelchair. I want to be able to control the wheelchair via RC (a-la battlebots), and I do not want to control the joystick via servo. I also want to leave the wheelchair's joystick controls intact and either solder another RC device in tandem with the joystick, or hijack the control by having an external switch that switches from either manual joystick, or RC Freq. I have some experience in electronics, but only in the troubleshooting arena. I can fix things if they are broken and can troubleshoot to the board level, but have no experience building bots and have no RC experience. The solution needs to be low cost please. I can solder build boards from directions. I just have no "vision" of how to put these 2 systems together. I think the words "pwm to analog" have been thrown around online, but I need to know more. Please point me to websites, or send me instructions and Ideas. The wheelchair will not be a wheelchair forever. R2-D2, Wall-E, and an RC Lawnmower are all in contention. Thanks in advance.?