Sim racing and game controllers - part 4 - Arduino leonardo project - TENSIOMETERS

Check the previous entries about the project: part1, part2, part3 and the video and problems.

So I'm still using the Arduino racing pad since 2 years. I'm still racing in LFS, now in Assetto Corsa with it. I've complained about what's bad about it. And now I've solved another issue that I've had - the crappy joysticks. I've used FSR402 tensiometers for both accelerator and braking. This seems much more natural than using the lever sticks. And precise. Now I can drive powerful cars with no ABS and TC in Assetto Corsa :)

Why tensiometers?

When I've started thinking about that crappy joysticks, I've looked at what the game consoles are doing for the trigger buttons on the pads:

• X360 pad uses a potentiometer with clever levers,
• Playstation uses tensiometers,
• X One uses Hall Effect sensors.

I wanted to buy the replacement parts for the X360 to check the levers, but the tensiometers are just cheaper. The Hall Effect sensors seem to be a very cool idea, but you really need to have an idea how to sort out the mechanics.

How does it look:

Bad. Ugly. But works.

I've placed the tensiometers along another edge of this beautiful lunch box. And now I can use both methods of controlling the speed of the car by just remapping controls. Frankly speaking - I haven't used the levers since I've got the tensiometers running.

Wiring FSR402 to Arduino:

Check this for examples of wiring and code: https://learn.adafruit.com/force-sensitive-resistor-fsr/using-an-fsr. After wiring the tensiometer properly you use it within the code like any other potentiometer.

Video:

Summary:

This just works. I'm using this for gaming weekly or biweekly (you know, 3 kids) for the last 3-4 months.

Using tensiometers for game controlers has another potential application. People making pedals for racing always look for methods to measure travel for acceleration and pressure for braking - to simulate real car hydraulics. All not ridiculously expensive steering wheels on the market use potentiometers for all pedals. And with a very simple mechanism (1 swing, some foam) you can get a pressure measuring tensiometer based pedal - you'll need a bigger tensiometer thou.

Code:

The requirements for having this running are described in the part3 of this "journey".

#include "HID-Project.h"

const int pinLed = LED_BUILTIN;

const int pinButton = 2;

// this is for printing to COM - set to 1 to get printouts

const int printuj = 0 ;

void setup() {

  pinMode(pinLed, OUTPUT);

  pinMode(pinButton, INPUT_PULLUP);

  Gamepad.begin();

  if ( printuj == 1 ) {

    Serial.begin(9600);

  }

}

void loop() {

  // limits for steering

  float steeringmin=0;

  float steeringmax=1023;

  // limits for joystick braking

  float brakemin=0;

  float brakemax=1023;

  // limits for joystick accelerating

  float accelmax=1023;

  // limits for tensometer acceleration and braking

  float brakemaxb=910;

  float accelmaxb=910;

  float accelmin=0;

  float min=-32767;

  float max=32767;

  float diff=max-min;

  float minB=-123;

  float maxB=+123;

  float diffB=maxB-minB;

  // steering

  float steer = (float)analogRead(0)/(steeringmax-steeringmin)*diff + min;

  // acceleration, braking for joysticks and for tensometers

  float accel = ((float)analogRead(2)/(accelmax-accelmin))*diff + min;

  float brake = ((float)analogRead(1)/(brakemax-brakemin))*diff + min;

  float accelb = ((float)analogRead(4)/(accelmaxb-accelmin))*diffB + minB;

  float brakeb = ((float)analogRead(3)/(brakemaxb-brakemin))*diffB + minB;

  // all 4 buttons readouts

  int gearup = digitalRead(2);

  int geardown = digitalRead(3);

  int gearupb = digitalRead(4);

  int geardownb = digitalRead(5);

  // idiotic deadzones for joystick

  if ((accel <= 3) and (accel >= -3)) {

    accel=0;

  }

  if ((brake <= 3) and (brake >= -3)) {

    brake=0;

  }

  // limits for tensometers

  if (accelb > maxB) {

    accelb=maxB;

  }

  if (brakeb > maxB) {

    brakeb=maxB;

  }

  // this is the COM printing

  if ( printuj == 1 ) {

        Serial.print ((int)steer);

        Serial.print (' ');

        Serial.print (analogRead(0));

        Serial.print (' ');

        Serial.print ((int)accel);

        Serial.print (' ');

        Serial.print (analogRead(2));

        Serial.print (' ');

        Serial.print ((int)brake);

        Serial.print (' ');

        Serial.print (analogRead(1));

        Serial.print (' ');

        Serial.print (gearup);

        Serial.print (' ');

        Serial.print (geardown);

        Serial.print (' ');

        Serial.print (gearupb);

        Serial.print (' ');

        Serial.print (geardownb);

                Serial.print (' ');

                Serial.print (analogRead(3));

                Serial.print (' ');

                Serial.print ((int)brakeb);

            Serial.print (' ');

                Serial.print (analogRead(4));

                Serial.print (' ');

                 Serial.print ((int)accelb);

        Serial.println (' ');

  }

 \\ button switching

 if (gearup == 0)

 {

   Gamepad.press(1);

 } else {

   Gamepad.release(1);

 }

 if (geardown == 0)

 {

   Gamepad.press(2);

 } else {

   Gamepad.release(2);

 }

 if (gearupb == 0)

 {

   Gamepad.press(3);

 } else {

   Gamepad.release(3);

 }

 if (geardownb == 0)

 {

   Gamepad.press(4);

 } else {

   Gamepad.release(4);

 }

 \\ output to axises. xA is 16bit, the rest I don't remember and it does not matter.

 Gamepad.xAxis((int)steer);

 Gamepad.yAxis((int)accel);

 Gamepad.rxAxis((int)brake);

 Gamepad.zAxis((int)accelb);

 Gamepad.rzAxis((int)brakeb);

 Gamepad.write();

}

Next step: getting some better chassis for the device.