Ch Pro Pedals Gameport to USB adapter

Ch Products is a manufacturer of control devices. I’ve been using CH Products since early ’90, and never had problems with them.

They are all plastic, but sound and well manufactured. The components are high quality, the design is sturdy, that’s why they last basically forever.

I’ve a set of CH Pro Pedals, with Gameport, but they are somewhat useless in modern computers.

There are Gameport to USB adapters in the market, but they are almost always plug and pray, as back in the Gameport era, the pin wiring was not standardized, so your device may or may not work. In particular for this very case, it is simply impossible for a Gameport to USB adapter to work, as only the Z axis (rudder) OR X and Y (toe brakes) are transmitted through the Gameport wiring (depending on the position of the CAR – PLANE toggle switch).

For this reason I thought of designing and manufacturing a simple, dedicated Gameport to USB adapter.

Design

Similarly to the TM Cougar USB adapter, the design is rather simple:

1. A connector, namely two DB-15 (with two rows), Female.
2. An Arduino Pro Micro Board.
3. A base PCB with the correct wiring between the DA-15 connector, and the Arduino Pro Micro.
4. An USB cable.

Luckily enough, back in those days, the wiring scheme of the port was directly written in the device’s manual (thanks to this post of Teensy forum).

The CH Pro Pedals have 3 connectors: 1 marked as Joystick (following CH Product data sheet, C connector, female), 1 marked as Gameport (following CH Product data sheet, B connector, male), and 1 marked as AUX (following CH Product data sheet, A connector, male).

Looking to the diagram of the wiring, depending on the position of the CAR – PLANE toggle switch the VIOLET cable (connected to the Rudder Pot) will or will not transmit to the Gameport Connector . On the other hand, AUX connector (A connector) will always (and only) carry the two pedals potentiometers signals, respectively on pin 3 and 6, that is A3 and A6.

Thus in order to have an external adapter, two DB-15 are needed (one connecting to the Gameport and the other to the AUX), in this way it is possible to have the three axis working at the same time (something that curiously wasn’t possible with the original CH Pro Pedals, at least to my understanding).

The PCB board is rather simple, following the above diagram, it connects the B1,B8,B9,B15 DB15 pins to the VCC of the Arduino Pro Micro, B4,B5,B12,B13 to the GND, and A3, A6, and B11 to A0,A1,A2, Arduino pins, which are ADC capable. I will be using one piece for the Gameport connector (so to connect the Z axis (rudder), and another to connect the AUX connector, so to have the Toe Brakes. As we are dealing with quite long cables, I added three capacitors to each potentiometers the axis to reduce jitter, they are wired to the ground.

Moreover I rewired the Pedals so to add ground to the three potentiometers. The original wiring, as shown in the pictures, was connecting only VCC and sensing pin to the potentiometers, no ground. As I will use an Arduino Micro, I opted to go for the conventional 3 pin VCC-Sensing-Ground, to wire the potentiometers. To do so I used the Yellow Cable ( I cutted it from the switch and soldered three ground cables to the potentiometers), which connects to the Red cable, and pin 13 of the Gameport Connector.

It is important to remark that the connector I chose, is the FEMALE (so if you look to the connector the first pin is on the first row on the right.

For the sake of completeness, in the diagram that follows, it is reported the Arduino Pro Micro pinout.

CH Pro Pedals disassemble

One dedicated chapter should be dedicated to the Pedals dis/assembly. It is nothing difficoult, but quite counter intuitive to me. To avoid any “surprise”, I think you may find useful these notes …

1. First of all, well, disconnect the pedals from the PC.
2. Everybody would start by disassembly the base (many screws there), I suggest to disassembly the pedals first, and remove them, as otherwise it will be very difficult to assembly back everything together.
3. Unscrew the screws on the light grey part of each pedal.
4. Remove the light grey plastic cover of the pedals. It will make you access to the potentiometer screw compartment.
5. Gently pull the potentiometer and unplug the connectors.
6. Unscrew the pedals from the base.
7. Remove the pedals.
8. Unscrew the base screws (plenty of them), don’t forget to unscrew the one covered by the Void Warranty sticker.
9. It is very likely that the screws which gives the spring back to the pedals will jump out of place.
10. You have full access to the pedals internal / movements.
11. If you wish to reduce the noise, you may add some plastic grease in the two housing where the rollers slide.

Arduino Code

The code implemented is pretty straightforward, simply providing 3 analogRead and assigning it to the joystick. I used Arduino Joystick Library, as it allows customizing the constructor (I will only save the 3 axis, and drop all the buttons and unneeded axis).

You can also find the most updated version of the code in my Github repository.

// Program used to setup an adapter for Ch Pro Pedals 
// Gameport to USB adapter.
//
// Giovanni Medici
// 2020-09-13 
//------------------------------------------------------------

#include <Joystick.h>

Joystick_ Joystick(JOYSTICK_DEFAULT_REPORT_ID,
                   JOYSTICK_TYPE_JOYSTICK, 0, 0, // 0 buttons, 0 hatswitches
                   false, false, false, true, true, true, // no x,y,z,Rx,Ry,Rz
                   false, false, false, false, false );         // Rudder, no Throttle, Accelerator and Brake, no Steering


void setup() {
  // Initialize the three axis
  //Joystick.setRxRange(0, 1023);
  //Joystick.setRyRange(0, 1023);
  //Joystick.setRzRange(0, 1023);


  Joystick.begin(false);

}

void loop() {

  //Serial.begin(9600);
  //reduceNoise(A1);
  int sensorA1 = analogRead(A1);
  //reduceNoise(A2);
  int sensorA2 = analogRead(A2);
  //reduceNoise(A3);
  int sensorA3 = analogRead(A3);
  //reduceNoise(A0);
  //int sensorA0 = analogRead(A0);
  
  Joystick.setRxAxis(1023-sensorA3);
  Joystick.setRyAxis(sensorA2);
  Joystick.setRzAxis(sensorA1);
  
  Joystick.sendState();
  delay(20);
  
  //Serial.print(" | A1 XAxisB: ");
  //Serial.print(sensorA1);
  //Serial.print(" | A2 YAxis: ");
  //Serial.print(sensorA2);
  //Serial.print(" | A3 XAxis: ");
  //Serial.println(sensorA3);
  
  

}

void reduceNoise(int pinNum)
{
  // This function reduces the noise in the pot
  // (particoularly effective for the Microstick).
  digitalWrite(pinNum, HIGH);
  delay(5);
  digitalWrite(pinNum, LOW);
  
}

The board

Here the final result, clean output, no noise whatsoever, possibly better than the ordinary CH Pro Pedals USB!