QMC6309 Magnetometer

//You can download the PCBCUPID_QMC6309 library from here : https://github.com/pcbcupid/PCBCUPID-QMC6309
#include <Wire.h>
#include "PCBCUPID_QMC6309.h"
#include "ExponentialFilter.h"

PCBCUPID_QMC6309 mag(Wire);

// Calibrated offsets
const float x_offset = 3485.0;
const float y_offset = 1290.0;
const float declination = 0.22;

// Filter object: 0.2 weight (20%)
ExponentialFilter headingFilter(0.2, 0.0);

void setup() {
  Serial.begin(115200);
  delay(1000);

  if (!mag.begin()) {
    Serial.println("Magnetometer init failed");
    while (1);
  }

  Serial.println("Heading with Exponential Filter");
}

void loop() {
  int16_t x, y, z;
  if (mag.readRaw(x, y, z)) {
    float x_cal = x - x_offset;
    float y_cal = y - y_offset;

    float heading = atan2(-x_cal, y_cal) + declination;
    if (heading < 0) heading += 2 * PI;
    if (heading > 2 * PI) heading -= 2 * PI;

    float headingDeg = heading * 180.0 / PI;

    // Apply exponential filter
    headingFilter.update(headingDeg);
    float smoothedHeading = headingFilter.get();

    Serial.print("Heading: ");
    Serial.print(smoothedHeading, 1);
    Serial.print("° (");
    Serial.print(mag.headingToDirection(smoothedHeading));
    Serial.println(")");
  }

  delay(200);
}

#include <Wire.h>
#include "PCBCUPID_QMC6309.h"
#include <U8g2lib.h>

// === OLED & Magnetometer ===
U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);
PCBCUPID_QMC6309 mag(Wire);

// === Graph Box Settings ===
const int graphX = 70;
const int graphY = 8;
const int graphWidth = 54;
const int graphHeight = 48;
const int baselineY = graphY + graphHeight / 2;
const int barHeightMax = graphHeight / 2;
const int barWidth = 5;
const int barSpacing = 18;
const int barStartX = graphX + 9;
const int barRange = 500;

// === Baseline Calibration ===
long avgX = 0, avgY = 0, avgZ = 0;
int samples = 0;

void setup() {
  Serial.begin(115200);
  Wire.begin();

  if (!mag.begin()) {
    Serial.println("QMC6309 not found!");
    while (1);
  }

  u8g2.begin();
}

void loop() {
  int16_t x, y, z;

  if (mag.readRaw(x, y, z)) {
    samples++;
    avgX = ((avgX * (samples - 1)) + x) / samples;
    avgY = ((avgY * (samples - 1)) + y) / samples;
    avgZ = ((avgZ * (samples - 1)) + z) / samples;

    u8g2.clearBuffer();

    // === Serial Debug ===
    Serial.print("X: "); Serial.print(x);
    Serial.print("  Y: "); Serial.print(y);
    Serial.print("  Z: "); Serial.println(z);

    // === Left Side Text ===
    u8g2.setFont(u8g2_font_5x8_tr);
    u8g2.setCursor(4, 10);  u8g2.print("X: "); u8g2.print(x);
    u8g2.setCursor(4, 20);  u8g2.print("Y: "); u8g2.print(y);
    u8g2.setCursor(4, 30);  u8g2.print("Z: "); u8g2.print(z);

    // === G-SENSE Label Box (Left) ===
    u8g2.setDrawColor(1);
    u8g2.drawBox(2, 38, 52, 12);   // G-SENSE Box
    u8g2.setDrawColor(0);
    u8g2.setCursor(8, 47); u8g2.print("G-SENSE");
    u8g2.setDrawColor(1);

    // === QMC6309 Label aligned to right end of box ===
    u8g2.setFont(u8g2_font_4x6_tr);
    u8g2.setCursor(54 - u8g2.getStrWidth("QMC6309"), 59);
    u8g2.print("QMC6309");

    // === Graph Box ===
    u8g2.drawFrame(graphX, graphY, graphWidth, graphHeight);
    u8g2.drawHLine(graphX, baselineY, graphWidth);  // Midline only

    // === Draw Bars (without vertical axis lines) ===
    drawBar(barStartX + barSpacing * 0, x - avgX, "X");
    drawBar(barStartX + barSpacing * 1, y - avgY, "Y");
    drawBar(barStartX + barSpacing * 2, z - avgZ, "Z");

    u8g2.sendBuffer();
  }

  delay(150);
}

void drawBar(int xCenter, int16_t delta, const char* label) {
  int percent = map(delta, -barRange, barRange, -100, 100);
  percent = constrain(percent, -100, 100);

  int barHeight = map(abs(percent), 0, 100, 0, barHeightMax);
  int yStart = (percent >= 0) ? (baselineY - barHeight) : baselineY;

  // Clip to graph box
  if (yStart < graphY) {
    barHeight -= (graphY - yStart);
    yStart = graphY;
  }
  if (yStart + barHeight > graphY + graphHeight) {
    barHeight = (graphY + graphHeight) - yStart;
  }

  // Draw the bar
  u8g2.drawBox(xCenter - barWidth / 2, yStart, barWidth, barHeight);

  // % text outside box
  u8g2.setFont(u8g2_font_4x6_tr);
  int percentY = (percent >= 0) ? (graphY - 2) : (graphY + graphHeight + 8);
  u8g2.setCursor(xCenter - 6, percentY);
  u8g2.print(percent); u8g2.print("%");

  // Axis label below bar
  u8g2.setCursor(xCenter - 2, graphY + graphHeight + 16);
  u8g2.print(label);
}