pi-lights/main.c

#include <wiringPi.h>
#include <stdio.h>
#include <stdbool.h>
#define LATCH_PIN   2
#define CLOCK_PIN   0
#define DATA_PIN    3
#define OFF         false, false, false
#define RED         true, false, false
#define GREEN       false, true, false
#define BLUE        false, false, true
#define PURPLE      true, false, true
typedef enum { LEFT, RIGHT } Side_t;
bool colorField[] = {
  false, // Left red
  false, // Left green
  false, // Left blue
  false, // Right red
  false, // Right green
  false, // Right blue
  false, // Unused bit
  false  // Unused bit
};
void write(bool mode) {
  delay(10);
  digitalWrite(DATA_PIN, mode);
  digitalWrite(CLOCK_PIN, true);
  digitalWrite(CLOCK_PIN, false);
  digitalWrite(DATA_PIN, false);
}
void flushPins() {
  digitalWrite(LATCH_PIN, true);
  digitalWrite(LATCH_PIN, false);
}
void updateColors() {
  flushPins();
  for(int i = 0; i < 8; i ++){
    write(colorField[i]);
  }
  flushPins();
}
void changeColor(Side_t side, bool red, bool green, bool blue) {
  short shift = 0;
  if(side == RIGHT) {
    shift = 3;
  }
  colorField[shift] = red;
  colorField[shift + 1] = green;
  colorField[shift + 2] = blue;
  updateColors();
  delay(1000);
}
void changeAllColors(bool red, bool green, bool blue) {
  changeColor(LEFT, red, green, blue);
  changeColor(RIGHT, red, green, blue);
}
int main(void) {
  wiringPiSetup();
  pinMode(DATA_PIN, OUTPUT);
  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(LATCH_PIN, OUTPUT);
  changeAllColors(OFF);
  updateColors();
  delay(1000);
  for(;;) {
    changeColor(LEFT, RED);
    changeColor(LEFT, OFF);
    changeColor(LEFT, GREEN);
    changeColor(LEFT, OFF);
    changeColor(LEFT, BLUE);
    changeColor(LEFT, OFF);
    changeColor(LEFT, PURPLE);
    changeColor(LEFT, OFF);
  }
}