Potentiometer for Gamebuino


By Tombuino, 3 years ago

Controls: D-Pad: [Arrows / WASD] - A: [J] - B: [K] - Menu: [U] - Home: [I]
Enjoy games at full speed with sound and lights on the Gamebuino META!
Emulator by aoneill

This is a short program written to desmonstrate the integration of a potentiometer on the Gamebuino Meta. It is intended as a code example to show how to handle the hardware. The commented code is available on the discourse post related to this creation for everyone to use and discuss.

Last comments

Thomas Thuret
3 years ago

Here is the source code with comments. Feel free to ask questions about it and reuse it yourself.

#include <Gamebuino-Meta.h>
//we include the math library to get access to sin() and cos() functions as well as a value of PI used in the program
#include <math.h>

//variable declaration for the potentimeter value and its conversion to angle
int32_t i32_pot_value;
int32_t i32_pot_angle;

//variable declaration for the point used to draw a line
int16_t i16_point_x;
int16_t i16_point_y;

//define of the analog pin used to plug the potentiometer, here it's A1
#define ANALOG A1

//define of our circle properties, here it has a radius of 15 and is centered on the screen
#define CIRCLE_R 15
#define CIRCLE_X gb.display.width()/2
#define CIRCLE_Y gb.display.height()/2

void setup() {
  // put your setup code here, to run once:


void loop() {
  // put your main code here, to run repeatedly:
  while (!gb.update());

  // the logic function will handle the math needed for the program

  //the draw function will handle the display of all the elements needed for the program

void  logic(){
  // we read the value from the potentiometer plugged to the analog port A1
  i32_pot_value = analogRead(ANALOG);
  // we convert the value from a range of 0 to 1023 to an angle within 360 degrees
  i32_pot_angle = (i32_pot_value * 360) / 1023;

  // we calculate the coordinates of a point on the circle perimeter corresponding to the value of the angle found above
  // note the multiplication by PI/180, this is because the angle we calculated in degrees must be converted to radians
  i16_point_x = CIRCLE_X + CIRCLE_R * cos(i32_pot_angle * M_PI/180);
  i16_point_y = CIRCLE_Y + CIRCLE_R * sin(i32_pot_angle * M_PI/180);

void  draw(){
  // the clear function is needed to reset the screen between each frame, otherwise frames would mix together and get messy

  // we print the value read from the potentiometer and its value when converted to an angle
  gb.display.print(" pot_value = ");
  gb.display.print("\n angle = ");

  // we draw the circle with the properties we defined at the beginning, its center's position and radius
  gb.display.drawCircle(CIRCLE_X, CIRCLE_Y, CIRCLE_R);
  // we draw a line between the center of the circle and the point on its perimeter corresponding to the potentiometer value we read
  gb.display.drawLine(CIRCLE_X, CIRCLE_Y, i16_point_x, i16_point_y);

// code by Thomas Thuret for Gamebuino