2.RGB-LED-Chaser.ino

2.RGB-LED-Chaser

This is an example of the ShiftRegisterOut class of the Control Surface library. It creates light effects using three 8-bit shift registers and some RGB LEDs.

Boards: 🛈

AVR, AVR USB, Nano Every, Nano 33 IoT, Nano 33 BLE, UNO R4, Pi Pico, Due, Teensy 3.x, ESP8266, ESP32

Connections

Connect three daisy-chained shift registers to the SPI pins.
Connect 8 RGB LEDs (+ current limiting resistors) to the outputs of the shift registers.

SCK   >───────────┬──────────────────────┬──────────────────────┐
          ┏━━━━━━━┷━━━━━━━┓      ┏━━━━━━━┷━━━━━━━┓      ┏━━━━━━━┷━━━━━━━┓
          ┃     SH_CP     ┃      ┃     SH_CP     ┃      ┃     SH_CP     ┃
MOSI  >───┨ DS        Q7S ┠──────┨ DS        Q7S ┠──────┨ DS        Q7S ┃
          ┃     ST_CP     ┃      ┃     ST_CP     ┃      ┃     ST_CP     ┃
          ┗━━━━━━━┯━━━━━━━┛      ┗━━━━━━━┯━━━━━━━┛      ┗━━━━━━━┯━━━━━━━┛
SS    >───────────┴──────────────────────┴──────────────────────┘

Remember to connect the enable pin of the shift register to ground and the master reset pin to Vcc in order to enable it.

The order of the colors doesn't matter. You can change them in software using the ShiftRegisterOutRGB::redBit, ShiftRegisterOutRGB::greenBit and ShiftRegisterOutRGB::blueBit constants.

If you wired the LEDs as RGB (red first, then green and then blue), the red bit is 0, the green bit is 1 and the blue bit is 2.
If you wired the LEDs as BGR (blue first, then green and then red), the red bit is 2, the green bit is 1 and the blue bit is 0.
Other combinations are possible as well.

Behavior

This example will turn on all red LEDs one by one, then turn them off one by one, next, it will turn on and off all green LEDs in the same manner, and finally the same for the blue LEDs. This is repeated indefinitely.

Demo

Written by Pieter P, 2018-07-13
https://github.com/tttapa/Arduino-Helpers

 
#include <Arduino_Helpers.h> // Include the Arduino Helpers library.
#include <AH/Hardware/ExtendedInputOutput/SPIShiftRegisterOut.hpp>
 
// If you wired your LEDs as RGB
const uint8_t ShiftRegisterOutRGB::redBit = 0;
const uint8_t ShiftRegisterOutRGB::greenBit = 1;
const uint8_t ShiftRegisterOutRGB::blueBit = 2;
 
// If you wired your LEDs as BGR
// const uint8_t ShiftRegisterOutRGB::redBit   = 2;
// const uint8_t ShiftRegisterOutRGB::greenBit = 1;
// const uint8_t ShiftRegisterOutRGB::blueBit  = 0;
 
// Create a new shift register output connected to pins 11, 13 and 10,
// shift the data out with the most significant bit first.
// There are 24 (= 3×8) outputs in total.
SPIShiftRegisterOut<24> sreg {SPI, SS, MSBFIRST};
 
void setup() {
  // Initialize the shift registers
  sreg.begin();
}
 
constexpr unsigned long delayTime = 50;
 
void loop() {
  // Red on
  for (uint8_t i = 0; i < 8; i++) {
    digitalWrite(sreg.red(i), HIGH);
    delay(delayTime);
  }
  // Red off
  for (uint8_t i = 0; i < 8; i++) {
    digitalWrite(sreg.red(i), LOW);
    delay(delayTime);
  }
  // Green on
  for (uint8_t i = 0; i < 8; i++) {
    digitalWrite(sreg.green(i), HIGH);
    delay(delayTime);
  }
  // Green off
  for (uint8_t i = 0; i < 8; i++) {
    digitalWrite(sreg.green(i), LOW);
    delay(delayTime);
  }
  // Blue on
  for (uint8_t i = 0; i < 8; i++) {
    digitalWrite(sreg.blue(i), HIGH);
    delay(delayTime);
  }
  // Blue off
  for (uint8_t i = 0; i < 8; i++) {
    digitalWrite(sreg.blue(i), LOW);
    delay(delayTime);
  }
}