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2017-06-26

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

Check the previous entries about the project: part1part2, 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.

1 komentarze:

Michael Steven pisze...

I just read your article and found it very helpful for those who are looking to get the cheap game controllers for their gaming but still there are many different options that are available in the market at an affordable cost. You can easily find the best controller for your PC gaming at an affordable cost. I'd recommend to take a look at this list of PC game controllers if you are looking to buy a new game controller for your PC gaming.

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