LED Bot

LED bot is the little diode that could.

Hardware Configuration

The following hardware is required to make an accurate clone of LED bot.

• Raspberry Pi 3b or above.
• Arduino with at least 1 serial port, capable of delivering 80 mA through 3 PWM pins. I used an Uno Rev 3.
• Breadboard
• RGB LED
• Resistors
• Hookup wire
• USB for powering Arduino and sending serial data

The code

#define RED 6
#define GREEN 9
#define BLUE 10
#define MIN 0
#define MAX 255

int redVal = 0;
int greenVal = 0;
int blueVal = 0;
int brightnessStep = 25;

void setup() {
  Serial.begin(9600);
  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(BLUE, OUTPUT);
}

void loop() {
  if (Serial.available() >= 2) {
    for (int i = 0; i < 2; i++) {
      command[i] = Serial.read();
    }
    switch(command[1]) {
      case 'd':
        switch(command[0]) {
          case 'r':
            redDown();
            break;
          case 'g':
            greenDown();
            break;
          case 'b':
            blueDown();
            break;
        }
        break;
      case 'u':
        switch(command[0]) {
          case 'r':
            redUp();
            break;
          case 'g':
            greenUp();
            break;
          case 'b':
            blueUp();
            break;
        }
        break;
      default:
        break;
    }
  }

  analogWrite(RED, redVal);
  analogWrite(GREEN, greenVal);
  analogWrite(BLUE, blueVal);

  // Clear the buffer if there's some weird data or something
  if(Serial.available() % 2 == 1) {
    Serial.end();
    Serial.begin(9600);
  }
}

void redUp() {
  redVal = threshold(redVal + brightnessStep);
}

void greenUp() {
  greenVal = threshold(greenVal + brightnessStep);
}

void blueUp() {
  blueVal = threshold(blueVal + brightnessStep);
}

void redDown() {
  redVal = threshold(redVal - brightnessStep);
}

void greenDown() {
  greenDown = threshold(greenVal - brightnessStep);
}

void blueDown() {
  blueDown = threshold(blueVal - brightnessStep);
}

int threshold(int val) {
  if (val < MIN) {
    return MIN;
  } else if (val > MAX) {
    return MAX;
  }
  return val;
}

Controller Configuration

I don't use a microphone for LEDBot. A loopback is enabled instead.

sudo modprobe snd-aloop
sudo echo 'snd-aloop' >> /etc/modules

For the current session, the device will show up as card 1, but after a reboot it'll show up as card 0.

I set my microphone device to 0,0 and my speaker device to 0,1.