PMGOHARIAN
Published © GPL3+

How to Make a Mini Oscilloscope at Home Using Arduino Nano

Make your own mini oscilloscope at home. It’s simple and easy to do!

IntermediateFull instructions provided6,623
How to Make a Mini Oscilloscope at Home Using Arduino Nano

Things used in this project

Hardware components

Arduino Nano R3
Arduino Nano R3
×1
0.96" OLED 64x128 Display Module
ElectroPeak 0.96" OLED 64x128 Display Module
×1
Tactile Switch, Top Actuated
Tactile Switch, Top Actuated
×9
1N4148 – General Purpose Fast Switching
1N4148 – General Purpose Fast Switching
×4

Software apps and online services

Arduino IDE
Arduino IDE

Story

Read more

Schematics

circuit

Code

code

C/C++
/*
     (_20190212_OLEDoscilloscope.ino)
     1285byte ram free
    2019/02/12 
*/

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <avr/pgmspace.h>               // PROGMEM
#include <EEPROM.h>

#define SCREEN_WIDTH 128                // OLED display width
#define SCREEN_HEIGHT 64                // OLED display height
#define REC_LENGTH 200                  // 

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     -1      // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

//
const char vRangeName[10][5] PROGMEM = {"A50V", "A 5V", " 50V", " 20V", " 10V", "  5V", "  2V", "  1V", "0.5V", "0.2V"}; // \0
const char * const vstring_table[] PROGMEM = {vRangeName[0], vRangeName[1], vRangeName[2], vRangeName[3], vRangeName[4], vRangeName[5], vRangeName[6], vRangeName[7], vRangeName[8], vRangeName[9]};
const char hRangeName[8][6] PROGMEM = {" 50ms", " 20ms", " 10ms", "  5ms", "  2ms", "  1ms", "500us", "200us"};          // (48
const char * const hstring_table[] PROGMEM = {hRangeName[0], hRangeName[1], hRangeName[2], hRangeName[3], hRangeName[4], hRangeName[5], hRangeName[6], hRangeName[7]};

int waveBuff[REC_LENGTH];      //  (RAM)
char chrBuff[10];              // 
String hScale = "xxxAs";
String vScale = "xxxx";

float lsb5V = 0.0055549;       // 5V0.005371 V/1LSB
float lsb50V = 0.051513;       // 50V 0.05371

volatile int vRange;           //   0:A50V, 1:A 5V, 2:50V, 3:20V, 4:10V, 5:5V, 6:2V, 7:1V, 8:0.5V
volatile int hRange;           // 0:50m, 1:20m, 2:10m, 3:5m, 4;2m, 5:1m, 6:500u, 7;200u
volatile int trigD;            // 0:1:
volatile int scopeP;           //  0:, 1:, 2:
volatile boolean hold = false; // 
volatile boolean paraChanged = false; //  true
volatile int saveTimer;        // EEPROM
int timeExec;                  // (ms)

int dataMin;                   // (min:0)
int dataMax;                   // (max:1023)
int dataAve;                   // 10 max:10230)
int rangeMax;                  // 
int rangeMin;                  // 
int rangeMaxDisp;              // max100
int rangeMinDisp;              // min
int trigP;                     // 
boolean trigSync;              // 
int att10x;                    // 1

void setup() {
  pinMode(2, INPUT_PULLUP);    // (int0
  pinMode(8, INPUT_PULLUP);    // Select
  pinMode(9, INPUT_PULLUP);    // Up
  pinMode(10, INPUT_PULLUP);   // Down
  pinMode(11, INPUT_PULLUP);   // Hold 
  pinMode(12, INPUT);          // 1/10
  pinMode(13, OUTPUT);         // 

  //     Serial.begin(115200);        // RAM
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x64
    //       Serial.println(F("SSD1306 failed"));
    for (;;);                               // Don't proceed, loop forever
  }
  loadEEPROM();                             // EEPROM
  analogReference(INTERNAL);                // ADC1.1Vvref)
  attachInterrupt(0, pin2IRQ, FALLING);     // 
  startScreen();                            // 
}

void loop() {
  digitalWrite(13, HIGH);
  setConditions();                          // RAM40
  readWave();                               //  (1.6ms )
  digitalWrite(13, LOW);                    //
  dataAnalize();                            // (0.4-0.7ms)
  writeCommonImage();                       // (4.6ms)
  plotData();                               // (5.4ms+)
  dispInf();                                // (6.2ms)
  display.display();                        // (37ms)
  saveEEPROM();                             // EEPROM
  while (hold == true) {                    // Hold
    dispHold();
    delay(10);
  }
}

void setConditions() {   // 
  // PROGMEM
  strcpy_P(chrBuff, (char*)pgm_read_word(&(hstring_table[hRange])));  // 
  hScale = chrBuff;                                                   // hScale

  // 
  strcpy_P(chrBuff, (char*)pgm_read_word(&(vstring_table[vRange])));  // 
  vScale = chrBuff;                                                   // vScale

  switch (vRange) {              // 
    case 0: {                    // Auto50V
        //        rangeMax = 1023;
        //        rangeMin = 0;
        att10x = 1;              // 
        break;
      }
    case 1: {                    // Auto 5V
        //        rangeMax = 1023;
        //        rangeMin = 0;
        att10x = 0;              // 
        break;
      }
    case 2: {                    // 50V
        rangeMax = 50 / lsb50V;  // 
        rangeMaxDisp = 5000;     // 100
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 1;              // 
        break;
      }
    case 3: {                    // 20V
        rangeMax = 20 / lsb50V;  // 
        rangeMaxDisp = 2000;
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 1;              // 
        break;
      }
    case 4: {                    // 10V
        rangeMax = 10 / lsb50V;  // 
        rangeMaxDisp = 1000;
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 1;              // 
        break;
      }
    case 5: {                    // 5V
        rangeMax = 5 / lsb5V;    // 
        rangeMaxDisp = 500;
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 0;              // 
        break;
      }
    case 6: {                    // 2V
        rangeMax = 2 / lsb5V;    // 
        rangeMaxDisp = 200;
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 0;              // 
        break;
      }
    case 7: {                    // 1V
        rangeMax = 1 / lsb5V;    // 
        rangeMaxDisp = 100;
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 0;              // 
        break;
      }
    case 8: {                    // 0.5V
        rangeMax = 0.5 / lsb5V;  // 
        rangeMaxDisp = 50;
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 0;              // 
        break;
      }
    case 9: {                    // 0.5V
        rangeMax = 0.2 / lsb5V;  // 
        rangeMaxDisp = 20;
        rangeMin = 0;
        rangeMinDisp = 0;
        att10x = 0;              // 
        break;
      }
  }
}

void writeCommonImage() {     // 
  display.clearDisplay();                   // (0.4ms)
  display.setTextColor(WHITE);              // 
  display.setCursor(86, 0);                 // Start at top-left corner
  display.println(F("av    V"));            // 1
  display.drawFastVLine(26, 9, 55, WHITE);  // 
  display.drawFastVLine(127, 9, 55, WHITE); // 

  display.drawFastHLine(24, 9, 7, WHITE);   // Max
  display.drawFastHLine(24, 36, 2, WHITE);  //
  display.drawFastHLine(24, 63, 7, WHITE);  //

  display.drawFastHLine(51, 9, 3, WHITE);   // Max
  display.drawFastHLine(51, 63, 3, WHITE);  //

  display.drawFastHLine(76, 9, 3, WHITE);   // Max
  display.drawFastHLine(76, 63, 3, WHITE);  //

  display.drawFastHLine(101, 9, 3, WHITE);  // Max
  display.drawFastHLine(101, 63, 3, WHITE); //

  display.drawFastHLine(123, 9, 5, WHITE);  // Max
  display.drawFastHLine(123, 63, 5, WHITE); // 

  for (int x = 26; x <= 128; x += 5) {
    display.drawFastHLine(x, 36, 2, WHITE); // ()
  }
  for (int x = (127 - 25); x > 30; x -= 25) {
    for (int y = 10; y < 63; y += 5) {
      display.drawFastVLine(x, y, 2, WHITE); // 3
    }
  }
}

void readWave() {                            // 
  if (att10x == 1) {                         // 1/10
    pinMode(12, OUTPUT);                     // 
    digitalWrite(12, LOW);                   // LOW
  } else {                                   // 
    pinMode(12, INPUT);                      // Hi-z
  }

  switch (hRange) {                          // 

    case 0: {                                // 50ms
        timeExec = 400 + 50;                 // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x07;              // 128 (arduino
        for (int i = 0; i < REC_LENGTH; i++) {     // 200
          waveBuff[i] = analogRead(0);       // 112s
          delayMicroseconds(1888);           // 
        }
        break;
      }

    case 1: {                                // 20ms
        timeExec = 160 + 50;                 // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x07;              // 128 (arduino
        for (int i = 0; i < REC_LENGTH; i++) {     // 200
          waveBuff[i] = analogRead(0);       // 112s
          delayMicroseconds(688);            // 
        }
        break;
      }

    case 2: {                                // 10 ms
        timeExec = 80 + 50;                  // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x07;              // 128 (arduino
        for (int i = 0; i < REC_LENGTH; i++) {     // 200
          waveBuff[i] = analogRead(0);       // 112s
          delayMicroseconds(288);            // 
        }
        break;
      }

    case 3: {                                // 5 ms
        timeExec = 40 + 50;                  // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x07;              // 128 (arduino
        for (int i = 0; i < REC_LENGTH; i++) {     // 200
          waveBuff[i] = analogRead(0);       // 112s
          delayMicroseconds(88);             // 
        }
        break;
      }

    case 4: {                                // 2 ms
        timeExec = 16 + 50;                  // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x06;              // 64 (0x1=2, 0x2=4, 0x3=8, 0x4=16, 0x5=32, 0x6=64, 0x7=128)
        for (int i = 0; i < REC_LENGTH; i++) {     // 200
          waveBuff[i] = analogRead(0);       // 56s
          delayMicroseconds(24);             // 
        }
        break;
      }

    case 5: {                                // 1 ms
        timeExec = 8 + 50;                   // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x05;              // 16 (0x1=2, 0x2=4, 0x3=8, 0x4=16, 0x5=32, 0x6=64, 0x7=128)
        for (int i = 0; i < REC_LENGTH; i++) {     // 200
          waveBuff[i] = analogRead(0);       // 28s
          delayMicroseconds(12);             // 
        }
        break;
      }

    case 6: {                                // 500us
        timeExec = 4 + 50;                   // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x04;              // 16(0x1=2, 0x2=4, 0x3=8, 0x4=16, 0x5=32, 0x6=64, 0x7=128)
        for (int i = 0; i < REC_LENGTH; i++) {     // 200
          waveBuff[i] = analogRead(0);       // 16s
          delayMicroseconds(4);              // 
          // 1.875snop 110.0625s @16MHz)
          asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
          asm("nop"); asm("nop"); asm("nop");
        }
        break;
      }

    case 7: {                                // 200us
        timeExec = 2 + 50;                   // (ms) EEPROM
        ADCSRA = ADCSRA & 0xf8;              // 3
        ADCSRA = ADCSRA | 0x02;              // :4(0x1=2, 0x2=4, 0x3=8, 0x4=16, 0x5=32, 0x6=64, 0x7=128)
        for (int i = 0; i < REC_LENGTH; i++) {
          waveBuff[i] = analogRead(0);       // 6s
          // 1.875snop 110.0625s @16MHz)
          asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
          asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
          asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        }
        break;
      }
  }
}

void dataAnalize() {                   // 
  int d;
  long sum = 0;

  // 
  dataMin = 1023;                         // 
  dataMax = 0;                            // 
  for (int i = 0; i < REC_LENGTH; i++) {  // 
    d = waveBuff[i];
    sum = sum + d;
    if (d < dataMin) {                    // 
      dataMin = d;
    }
    if (d > dataMax) {                    // 
      dataMax = d;
    }
  }

  // 
  dataAve = (sum + 10) / 20;               // 10

  // max,min
  if (vRange <= 1) {                       // Auto1
    rangeMin = dataMin - 20;               // -20
    rangeMin = (rangeMin / 10) * 10;       // 10
    if (rangeMin < 0) {
      rangeMin = 0;                        // 0
    }
    rangeMax = dataMax + 20;               // +20
    rangeMax = ((rangeMax / 10) + 1) * 10; // 10
    if (rangeMax > 1020) {
      rangeMax = 1023;                     // 10201023
    }

    if (att10x == 1) {                            // 
      rangeMaxDisp = 100 * (rangeMax * lsb50V);   // ADC
      rangeMinDisp = 100 * (rangeMin * lsb50V);   // 
    } else {                                      // 
      rangeMaxDisp = 100 * (rangeMax * lsb5V);
      rangeMinDisp = 100 * (rangeMin * lsb5V);
    }
  } else {                                   // 
    // 
  }

  // 
  for (trigP = ((REC_LENGTH / 2) - 51); trigP < ((REC_LENGTH / 2) + 50); trigP++) { // 
    if (trigD == 0) {                        // 0
      if ((waveBuff[trigP - 1] < (dataMax + dataMin) / 2) && (waveBuff[trigP] >= (dataMax + dataMin) / 2)) {
        break;                              // 
      }
    } else {                                // 0
      if ((waveBuff[trigP - 1] > (dataMax + dataMin) / 2) && (waveBuff[trigP] <= (dataMax + dataMin) / 2)) {
        break;
      }                                    // 
    }
  }
  trigSync = true;
  if (trigP >= ((REC_LENGTH / 2) + 50)) {  // 
    trigP = (REC_LENGTH / 2);
    trigSync = false;                      // Unsync
  }
}

void startScreen() {                 // 
  display.clearDisplay();
  display.setTextSize(1);            // 2
  display.setTextColor(WHITE);       //
  display.setCursor(10, 25);         //
  display.println(F("PM.GOHARIAN"));   // 
  display.setCursor(10, 45);         //
  display.println(F("Pen oscope"));
  display.display();                 // 
  delay(5000);
  display.clearDisplay();
  display.setTextSize(1);            // 
}

void dispHold() {                            // Hold
  display.fillRect(32, 12, 24, 8, BLACK);    // 4
  display.setCursor(32, 12);
  display.print(F("Hold"));                  // Hold 
  display.display();                         //
}

void dispInf() {                             // 
  float voltage;
  // 
  display.setCursor(2, 0);                   // 
  display.print(vScale);                     // 
  if (scopeP == 0) {                         // 
    display.drawFastHLine(0, 7, 27, WHITE);  // 
    display.drawFastVLine(0, 5, 2, WHITE);
    display.drawFastVLine(26, 5, 2, WHITE);
  }

  // 
  display.setCursor(34, 0);                  //
  display.print(hScale);                     // (time/div)
  if (scopeP == 1) {                         // 
    display.drawFastHLine(32, 7, 33, WHITE); // 
    display.drawFastVLine(32, 5, 2, WHITE);
    display.drawFastVLine(64, 5, 2, WHITE);
  }

  // 
  display.setCursor(75, 0);                  // 
  if (trigD == 0) {
    display.print(char(0x18));               // 
  } else {
    display.print(char(0x19));               //               
  }
  if (scopeP == 2) {      // 
    display.drawFastHLine(71, 7, 13, WHITE); // 
    display.drawFastVLine(71, 5, 2, WHITE);
    display.drawFastVLine(83, 5, 2, WHITE);
  }

  // 
  if (att10x == 1) {                         // 10
    voltage = dataAve * lsb50V / 10.0;       // 50V
  } else {
    voltage = dataAve * lsb5V / 10.0;        // 5V
  }
  dtostrf(voltage, 4, 2, chrBuff);           // x.xx 
  display.setCursor(98, 0);                  // 
  display.print(chrBuff);                    // 
  //  display.print(saveTimer);                  // 

  // 
  voltage = rangeMaxDisp / 100.0;            // Max
  if (vRange == 1 || vRange > 4) {           // 5VAuto5V
    dtostrf(voltage, 4, 2, chrBuff);         //  *.** 
  } else {                                   //
    dtostrf(voltage, 4, 1, chrBuff);         // **.* 
  }
  display.setCursor(0, 9);
  display.print(chrBuff);                    // Max

  voltage = (rangeMaxDisp + rangeMinDisp) / 200.0; // 
  if (vRange == 1 || vRange > 4) {           // 5VAuto5V
    dtostrf(voltage, 4, 2, chrBuff);         // 2
  } else {                                   //
    dtostrf(voltage, 4, 1, chrBuff);         // 1
  }
  display.setCursor(0, 33);
  display.print(chrBuff);                    // 

  voltage = rangeMinDisp / 100.0;            // Min
  if (vRange == 1 || vRange > 4) {           // 5VAuto5V
    dtostrf(voltage, 4, 2, chrBuff);         // 2
  } else {
    dtostrf(voltage, 4, 1, chrBuff);         // 1
  }
  display.setCursor(0, 57);
  display.print(chrBuff);                    // Min

  // 
  if (trigSync == false) {                   // 
    display.setCursor(60, 55);               // 
    display.print(F("Unsync"));              // Unsync 
  }
}

void plotData() {                    // 
  long y1, y2;
  for (int x = 0; x <= 98; x++) {
    y1 = map(waveBuff[x + trigP - 50], rangeMin, rangeMax, 63, 9); // 
    y1 = constrain(y1, 9, 63);                                     // 
    y2 = map(waveBuff[x + trigP - 49], rangeMin, rangeMax, 63, 9); //
    y2 = constrain(y2, 9, 63);                                     //
    display.drawLine(x + 27, y1, x + 28, y2, WHITE);               // 
  }
}

void saveEEPROM() {                    // EEPROM
  if (paraChanged == true) {           // 
    saveTimer = saveTimer - timeExec;  // 
    if (saveTimer < 0) {               // 
      paraChanged = false;             // 
      EEPROM.write(0, vRange);        // 
      EEPROM.write(1, hRange);
      EEPROM.write(2, trigD);
      EEPROM.write(3, scopeP);
    }
  }
}

void loadEEPROM() {                // EEPROM
  int x;
  x = EEPROM.read(0);             // vRange
  if ((x < 0) || (x > 9)) {        // 0-9
    x = 3;                         // 
  }
  vRange = x;

  x = EEPROM.read(1);             // hRange
  if ((x < 0) || (x > 7)) {        // 0-9
    x = 3;                         // 
  }
  hRange = x;
  x = EEPROM.read(2);             // trigD
  if ((x < 0) || (x > 1)) {        // 0-9
    x = 1;                         // 
  }
  trigD = x;
  x = EEPROM.read(3);             // scopeP
  if ((x < 0) || (x > 2)) {        // 0-9
    x = 1;                         // 
  }
  scopeP = x;
}

void pin2IRQ() {                   // Pin2(int0)
  //pin8,9,10,11Pin2
  //

  int x;                           // 
  x = PINB;                        // B

  if ( (x & 0x07) != 0x07) {       // 3High
    saveTimer = 5000;              // EEPROM(ms
    paraChanged = true;            // ON
  }

  if ((x & 0x01) == 0) {
    scopeP++;
    if (scopeP > 2) {
      scopeP = 0;
    }
  }

  if ((x & 0x02) == 0) {           // UP
    if (scopeP == 0) {             // 
      vRange++;
      if (vRange > 9) {
        vRange = 9;
      }
    }
    if (scopeP == 1) {             // 
      hRange++;
      if (hRange > 7) {
        hRange = 7;
      }
    }
    if (scopeP == 2) {             // 
      trigD = 0;                   // 
    }
  }

  if ((x & 0x04) == 0) {           // DOWN
    if (scopeP == 0) {             // 
      vRange--;
      if (vRange < 0) {
        vRange = 0;
      }
    }
    if (scopeP == 1) {             // 
      hRange--;
      if (hRange < 0) {
        hRange = 0;
      }
    }
    if (scopeP == 2) {             // 
      trigD = 1;                   // 
    }
  }

  if ((x & 0x08) == 0) {           // HOLD
    hold = ! hold;                 // 
  }
}

Credits

PMGOHARIAN

PMGOHARIAN

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what's up everyone its PM.GOHARIAN . I make electronic content , if want see more just subscribe me on youtube and IG . peace !

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