4.VULEDs.ino

4.VULEDs

This example demonstrates the use of the VULEDs class that displays the VU or level meters from your DAW as an LED bar graph.

Shift registers are used to drive the LEDs.

Boards: 🛈

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

Connections

• SS: 74HC595 ST_CP
• MOSI: 74HC595 DS
• SCK: 74HC595 SH_CP
• A0: Push button (to ground, internal pull-up resistor will be used)

Connect an LED (and series resistor) between each of the first 12 outputs of the shift registers and ground.

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

Behavior

The LEDs display the level of the first track in your DAW.
When the push button is pressed, the VU meter switches from bar mode to dot mode and back.

Mapping

Map the Arduino as a Mackie Control Universal in your DAW.

Written by PieterP, 2019-12-09
https://github.com/tttapa/Control-Surface

 
#include <Control_Surface.h>
 
USBMIDI_Interface midi;
 
// Instantiate two daisy-chained shift register with the SPI slave select pin as
// latch pin, most significant bit first, and a total of 16 outputs.
SPIShiftRegisterOut<16> sreg {SPI, SS, MSBFIRST};
 
// Instantiate a VULEDs object with 12 LEDs.
MCU::VULEDs<12> vu {
  sreg.pins().slice<0, 11>(), // first 12 pins of the shift registers
  1,                          // track number [1, 8]
  MCU::VUDecay::Default,      // how long does it take for the meter to decay
};
 
// If you don't want to use shift registers, you can just specify a list of pin
// numbers:
//
//   MCU::VULEDs<12> vu {
//     {{2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}}, // Arduino pin numbers
//     1,                      // track number [1, 8]
//     MCU::VUDecay::Default,  // how long does it take for the meter to decay
//   };
 
// You can also use a different number of LEDs, but keep in mind that the MCU
// protocol sends the level on a scale from 0 to 12.
// If you use 24 LEDs, for example, the LEDs will turn on in groups of 2 at a
// time.
 
// Push button to switch between dot and bar mode.
Button dotBarModeButton = A0;
 
void setup() {
  Control_Surface.begin();
  dotBarModeButton.begin();
}
 
void loop() {
  Control_Surface.loop();
  if (dotBarModeButton.update() == Button::Falling) // when button is pressed
    vu.toggleMode(); // toggle between dot and bar mode
}