VU-Bridge.ino

This is an example on how to use an OLED display to display the VU meters and mute/solo states of the eight first tracks, by using the Arduino as a Mackie Control Universal.

This is an example on how to use an OLED display to display the VU meters and mute/solo states of the eight first tracks, by using the Arduino as a Mackie Control Universal.

VU-Bridge

Boards: 🛈

Teensy 3.x, Teensy 4.0

If you want to display more than eight tracks, have a look at the VU-Bridge-Dual-Display.ino example, that uses MCU Extenders to display up to 32 tracks.

The OLED display uses a RAM frame buffer of 1 KiB (128×64 pixels / 8 pixels per byte). This is a significant amount for AVR boards like the Arduino UNO, Nano, Leonardo, etc. Keep in mind that you might run out of memory, and that you'll need a more powerful board.

Connections

This example drives two SSD1306 OLED displays over SPI

• SCK: SSD1306 D0
• MOSI: SSD1306 D1
• 19: SSD1306 DC
• 18: SSD1306 CS

Add a capacitor between the reset pin of the display and ground, and a resistor from reset to 3.3V. The values are not critical, 0.1µF and 10kΩ work fine.
You do need some way to reset the display, without it, it won't work.
Alternatively, you could use an IO pin from the Arduino to reset the display, but this just "wastes" a pin.

Note

Don't forget that most OLED displays are 3.3V only, so connecting a display to a 5V Arduino directly will destroy it!

Behavior

Map "Control Surface" as a Mackie Control Universal unit in your DAW.

The first display should now display the level meters and mute/solo states of the first 8 tracks.

Note

There seem to be some differences in the way some applications handle VU meters: some expect the hardware to decay automatically, some don't.
If you notice that the meters behave strangely, try both decay options of the MCU::VUDecay class, or try a different decay time.

Demo

 
#include <Control_Surface.h> // Include the Control Surface library
// Include the display interface you'd like to use
#include <Display/DisplayInterfaces/DisplayInterfaceSSD1306.hpp>
 
// ----------------------------- MIDI Interface ----------------------------- //
// ========================================================================== //
 
// Instantiate a MIDI interface to use for the Control Surface.
USBMIDI_Interface midi;
 
// ----------------------------- Display setup ------------------------------ //
// ========================================================================== //
 
constexpr uint8_t SCREEN_WIDTH = 128;
constexpr uint8_t SCREEN_HEIGHT = 64;
 
constexpr int8_t OLED_DC = 19;    // Data/Command pin of the display
constexpr int8_t OLED_reset = -1; // Use the external RC circuit for reset
constexpr int8_t OLED_CS = 18;    // Chip Select pin of the display
 
constexpr uint32_t SPI_Frequency = SPI_MAX_SPEED;
 
// Instantiate the displays
Adafruit_SSD1306 ssd1306Display = {
  SCREEN_WIDTH, SCREEN_HEIGHT,
  &SPI, OLED_DC, OLED_reset, OLED_CS, SPI_Frequency
};
 
// --------------------------- Display interface ---------------------------- //
// ========================================================================== //
 
// Define and instantiate a display interface
class MySSD1306_DisplayInterface : public SSD1306_DisplayInterface {
  public:
    MySSD1306_DisplayInterface(Adafruit_SSD1306 &display)
      : SSD1306_DisplayInterface(display) {}
 
    void begin() override {
        if(!disp.begin())
            FATAL_ERROR(F("SSD1306 allocation failed."), 0x1306);
        SSD1306_DisplayInterface::begin(); // If you override the begin method,
                                           // remember to call the super class
                                           // method
    }
 
    void drawBackground() override {
      disp.drawFastHLine(0, 52, 128, WHITE);
      disp.drawRect(0, 0, 128, 64, WHITE);
    }
} display = ssd1306Display;
 
// -------------------------- MIDI Input Elements --------------------------- //
// ========================================================================== //
 
NoteValue mute[8] = {
  { MCU::MUTE_1 }, // The mute status of the first track
  { MCU::MUTE_2 },
  { MCU::MUTE_3 },
  { MCU::MUTE_4 },
  { MCU::MUTE_5 },
  { MCU::MUTE_6 },
  { MCU::MUTE_7 },
  { MCU::MUTE_8 },
};
 
NoteValue solo[8] = {
  { MCU::SOLO_1 }, // The solo status of the first track
  { MCU::SOLO_2 },
  { MCU::SOLO_3 },
  { MCU::SOLO_4 },
  { MCU::SOLO_5 },
  { MCU::SOLO_6 },
  { MCU::SOLO_7 },
  { MCU::SOLO_8 },
};
 
// const auto decay = MCU::VUDecay::Hold;
const auto decay = MCU::VUDecay::Default;
 
// VU meters
MCU::VU VUMeters[8] = {
  { 1, decay }, // The VU meter for the first track,
  { 2, decay }, // second track, etc.
  { 3, decay },
  { 4, decay },
  { 5, decay },
  { 6, decay },
  { 7, decay },
  { 8, decay },
};
 
// ---------------------------- Display Elements ---------------------------- //
// ========================================================================== //
 
MCU::VUDisplay<> vuDisp[8] = {
  // Draw the first VU meter to the display, at position (2, 48),
  // (12) pixels wide, blocks of (3) pixels high, a spacing between 
  // blocks of (1) pixel, and draw in white.
  { display, VUMeters[0], { 2 + 16 * 0, 50 }, 12, 3, 1, WHITE },
  { display, VUMeters[1], { 2 + 16 * 1, 50 }, 12, 3, 1, WHITE },
  { display, VUMeters[2], { 2 + 16 * 2, 50 }, 12, 3, 1, WHITE },
  { display, VUMeters[3], { 2 + 16 * 3, 50 }, 12, 3, 1, WHITE },
  { display, VUMeters[4], { 2 + 16 * 4, 50 }, 12, 3, 1, WHITE },
  { display, VUMeters[5], { 2 + 16 * 5, 50 }, 12, 3, 1, WHITE },
  { display, VUMeters[6], { 2 + 16 * 6, 50 }, 12, 3, 1, WHITE },
  { display, VUMeters[7], { 2 + 16 * 7, 50 }, 12, 3, 1, WHITE },
};
 
BitmapDisplay<> muteDisp[8] = {
  // Draw the first mute indicator to the display, at position (4, 54),
  // using bitmap icon mute_7 with a white foreground color. 
  { display, mute[0], XBM::mute_7, { 4 + 16 * 0, 54 }, WHITE },
  { display, mute[1], XBM::mute_7, { 4 + 16 * 1, 54 }, WHITE },
  { display, mute[2], XBM::mute_7, { 4 + 16 * 2, 54 }, WHITE },
  { display, mute[3], XBM::mute_7, { 4 + 16 * 3, 54 }, WHITE },
  { display, mute[4], XBM::mute_7, { 4 + 16 * 4, 54 }, WHITE },
  { display, mute[5], XBM::mute_7, { 4 + 16 * 5, 54 }, WHITE },
  { display, mute[6], XBM::mute_7, { 4 + 16 * 6, 54 }, WHITE },
  { display, mute[7], XBM::mute_7, { 4 + 16 * 7, 54 }, WHITE },
};
 
BitmapDisplay<> soloDisp[8] = {
  // Draw the first solo indicator to the display, at position (4, 54),
  // using bitmap icon solo_7 with a white foreground color.
  { display, solo[0], XBM::solo_7, { 4 + 16 * 0, 54 }, WHITE },
  { display, solo[1], XBM::solo_7, { 4 + 16 * 1, 54 }, WHITE },
  { display, solo[2], XBM::solo_7, { 4 + 16 * 2, 54 }, WHITE },
  { display, solo[3], XBM::solo_7, { 4 + 16 * 3, 54 }, WHITE },
  { display, solo[4], XBM::solo_7, { 4 + 16 * 4, 54 }, WHITE },
  { display, solo[5], XBM::solo_7, { 4 + 16 * 5, 54 }, WHITE },
  { display, solo[6], XBM::solo_7, { 4 + 16 * 6, 54 }, WHITE },
  { display, solo[7], XBM::solo_7, { 4 + 16 * 7, 54 }, WHITE },
};
 
// --------------------------------- Setup ---------------------------------- //
// ========================================================================== //
 
void setup() {
  Control_Surface.begin(); // Initialize Control Surface
}
 
// ---------------------------------- Loop ---------------------------------- //
// ========================================================================== //
 
void loop() {
  Control_Surface.loop(); // Refresh all elements
}