How to make an extremely simple but visually effective VU meter at 0.9 inches Oled displays SSD 1306

This time I will show you how to make analog-style stereo VU meters on small 0.96 inch OLED displays. Some time ago I received small yellow OLED displays that are ideal for this purpose.

The device is made according to the instructions of "stevenart" in the arduino.cc forum where you can also find the original code(for SH1106 Oled). Specifically in this case the codes are slightly modified(SSD1306 Oled), and in the hardware, part is added a simple input circuit (envelope follower) so that the VU meter can be connected directly to the output of the audio amplifier. The device is very simple to build and contains only a few components.

As can be seen, the VU meter contains two identical assemblies for each channel separately. It can be made with just one Arduino, but in that case, OLED displays must have different I2C addresses. My OLED displays had the same I2C address, so I had to make two identical devices, which cost only a few dollars more as much as the Arduino. However, it is better if you are able to get Oled displays with different addresses, or if there is a possibility, to change the address of one display with soldering according to some of the instructions given online. Below are codes for VU meters with linear scale and arc scale. For Reverse light modification it is necessary to do the following:

In viod setup after :

display.clearDisplay();

We need to add :

display.invertDisplay(true);

So the components of one channel are:

- Arduino Microcontroller

- SSD1306 small Oled display 0.96"

- two resistors

- one capacitor

- And potentiometer

The other channel is identical. Let me mention that the movement of the arrows is smooth when viewed live. Finally, the device is mounted in a suitable box made of PVC material and lined with self-adhesive colored wallpaper.

Untitled Sketch_bb.jpg
        /*  OLEDMeter was written to utilize any 128x64 display. I have only seen marginal attempts to
 *  animate meters and I hope this one will set a standard. Please feel free to modify and share
 *  this code for any 128x64 LCD or OLED. OLEDMeter sketch was written for use with I2C SSD1306.
 *  This code must be modified to work with other display devices.
 *  
 *  Working portion of code was taken from Adafruit Example Sound Level Sketch for the
 *  Adafruit Microphone Amplifier
 *  https://learn.adafruit.com/adafruit-microphone-amplifier-breakout/measuring-sound-levels
 *  
 *  Remaining code was written by Greg Stievenart with no claim to or any images or information 
 *  provided in this code. Freely published May 26, 2016.
 *  
 *  Software to convert background mask to 128x64 at: http://www.ablab.in/image2glcd-software/
 *  
 *  IMPORTANT: Sound source must be grounded to the Arduino or other MCU's to work. Usually the
 *  base sleeve contact on TRS or TRRS connector is the ground.
 */

#include <Wire.h>                     // requried to run I2C SSD1306
#include <SPI.h>                      // requried to run I2C SSD1306
#include <Adafruit_GFX.h>             // https://github.com/adafruit/Adafruit-GFX-Library
#include <Adafruit_SSD1306.h>          // https://github.com/wonho-maker/Adafruit_SSD1306

#define OLED_RESET 4                  // reset required for SSD1306

Adafruit_SSD1306 display(OLED_RESET);  // reset required for SSD1306

int analogInput = A0;                 // analog input for outside audio source
int hMeter = 65;                      // horizontal center for needle animation
int vMeter = 85;                      // vertical center for needle animation (outside of dislay limits)
int rMeter = 80;                      // length of needle animation or arch of needle travel

const int sampleWindow = 50;          // sample window width in mS (50 mS = 20Hz)
unsigned int sample;

// VU meter background mask image:
static const unsigned char PROGMEM VUMeter[] = { 
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};

void setup(){

  pinMode(analogInput, INPUT);                             // analog input for outside audio source
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);                // needed for SSD1306 display
  display.clearDisplay();                                  // clears display from any library info displayed
  
  
}

void loop(){

/***********************************************************************
 Start of code taken from Adafruit Example Sound Level Sketch for the 
 Adafruit Microphone Amplifier
************************************************************************/
  
  unsigned long startMillis = millis();                    // start of sample window
  unsigned int PeaktoPeak = 0;                             // peak-to-peak level
  unsigned int SignalMax = 0;
  unsigned int SignalMin = 1024;

  while ( millis() - startMillis < sampleWindow ){

    sample = analogRead(analogInput);
    if (sample < 1024) {

      if (sample > SignalMax){

        SignalMax = sample;                                // saves just the max levels
      }

      else if (sample < SignalMin){

        SignalMin = sample;                                // saves just the min levels
      }
    }
  }

  PeaktoPeak = SignalMax - SignalMin;                      // max - min = peak-peak amplitude
  float MeterValue = PeaktoPeak * 330 / 1024;              // convert volts to arrow information

/****************************************************
 End of code taken from Adafruit Sound Level Sketch
*****************************************************/
  
  MeterValue = MeterValue - 34;                            // shifts needle to zero position
  display.clearDisplay();                                  // refresh display for next step
  display.drawBitmap(0, 0, VUMeter, 128, 64, WHITE);       // draws background
  int a1 = (hMeter + (sin(MeterValue / 57.296) * rMeter)); // meter needle horizontal coordinate
  int a2 = (vMeter - (cos(MeterValue / 57.296) * rMeter)); // meter needle vertical coordinate
  display.drawLine(a1, a2, hMeter, vMeter, WHITE);         // draws needle
  display.display();
}
    
Mirko Pavleski
Electronics , Arduino , Physics