Fixing the Dreamcast Race Controller's dead zone with a simple microcontroller circuit
Tuesday, 21st May 2019
I recently bought myself a Race Controller wheel for the Sega Dreamcast and was a little disappointed with the way that it performed. I had read reviews online before buying it and some did mention that it didn't handle particularly well but others did mention that it was about the best controller available for the system so I didn't feel it was too risky a purchase.
The issues I have with the wheel stem from its excessively large dead zone – you need to turn the wheel quite far before your car starts to turn, making it feel sluggish and unresponsive.
Fortunately, the wheel hardware is very simple internally – a 100KΩ potentiometer is used to detect the wheel's position and it outputs an analogue voltage to the controller PCB. We can take advantage of that to insert our own circuit between the potentiometer and controller PCB to sample the wheel position, add an large offset to it to push it outside the dead zone and then output that corrected voltage to the stock PCB. This will then cancel out the offset as part of the large dead zone before sending the position to the console.
The video above goes into more detail about how this circuit works as well as illustrating the problem with the stock dead zone. For more information and to download the code and circuit diagram please see the De-Dead Zone product page.