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4 · Displays & buses

MPU6050 inertial unit

Expert30 min

Goal

Read the accelerometer and gyroscope over I²C.

Why it matters

Those six axes are the heart of every drone, phone or smartwatch.

Steps

  1. 01Drag in the MPU6050 (SDA A4, SCL A5, address 0x68).
  2. 02Load the starter sketch: it wakes the sensor and reads its registers.
  3. 03Run it, open the Scenario panel and tilt the virtual board.
  4. 04Watch the values follow the sliders in the serial monitor.

Starter sketch

// MPU6050 over I2C — raw register reads, no external library needed.
#include <Wire.h>

const uint8_t MPU = 0x68;

void writeReg(uint8_t reg, uint8_t val) {
  Wire.beginTransmission(MPU);
  Wire.write(reg);
  Wire.write(val);
  Wire.endTransmission();
}

int16_t readWord(uint8_t reg) {
  Wire.beginTransmission(MPU);
  Wire.write(reg);
  Wire.endTransmission(false);
  Wire.requestFrom(MPU, (uint8_t)2);
  int16_t hi = Wire.read();
  int16_t lo = Wire.read();
  return (hi << 8) | lo;
}

void setup() {
  Serial.begin(9600);
  Wire.begin();
  writeReg(0x6B, 0x00);   // wake up
  writeReg(0x1B, 0x00);   // gyro +/- 250 deg/s
  writeReg(0x1C, 0x00);   // accel +/- 2 g
  Serial.println("MPU6050 ready");
}

void loop() {
  float ax = readWord(0x3B) / 16384.0;
  float ay = readWord(0x3D) / 16384.0;
  float az = readWord(0x3F) / 16384.0;
  float gz = readWord(0x47) / 131.0;

  Serial.print("accel ");
  Serial.print(ax); Serial.print(" ");
  Serial.print(ay); Serial.print(" ");
  Serial.print(az);
  Serial.print("  gyroZ ");
  Serial.println(gz);

  delay(300);
}

This tutorial runs inside the Circuitly simulator: your wiring and your code are checked automatically at every step.

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