VU-Meter-Bridge.ino

VU-Meter-Bridge

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 modified to work with the ESP32 only, using MIDI over Bluetooth Low Energy.

Boards: 🛈

ESP32

Connections

This example drives two SSD1306 OLED displays over SPI

• SCK: SSD1306 D0
• MOSI: SSD1306 D1
• 15: SSD1306 DC
• 2: 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 ESP32 to reset the display, but this just "wastes" a pin.

Behavior

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

Mapping

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

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 MCU::VUDecay::Hold and MCU::VUDecay::Default, or try a different decay time.

Demo

Written by PieterP, 2019-08-09
https://github.com/tttapa/Control-Surface

 
#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.
BluetoothMIDI_Interface midi;
 
// ----------------------------- Display setup ------------------------------ //
// ========================================================================== //
 
constexpr uint8_t SCREEN_WIDTH = 128;
constexpr uint8_t SCREEN_HEIGHT = 64;
 
constexpr int8_t OLED_DC = 15;    // Data/Command pin of the display
constexpr int8_t OLED_reset = -1; // Use the external RC circuit for reset
constexpr int8_t OLED_CS = 2;     // 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 {
    // Initialize the Adafruit_SSD1306 display
    if (!disp.begin())
      FATAL_ERROR(F("SSD1306 allocation failed."), 0x1306);
 
    // If you override the begin method,remember to call the superclass method
    SSD1306_DisplayInterface::begin();
  }
 
  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},
};
 
constexpr unsigned int decay = MCU::VUDecay::Hold;
// Try this option if your DAW doesn't decay the VU meters automatically:
//   constexpr unsigned int decay = 60; // milliseconds to decay one block
 
// VU meters
MCU::VU VUMeters[8] {
  {1, decay}, // The VU meter for the first track, decay time as specified above
  {2, decay}, {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, 50),
  // (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
}