Graham Chow
Published © MIT

MPU-6050 for Windows IoT

This is a MPU-6050 Windows IoT solution that uses interrupts, fifo, constant sampling (50hz) with no DMP.

BeginnerFull instructions provided9,362
MPU-6050 for Windows IoT

Things used in this project

Hardware components

Raspberry Pi 2 Model B
Raspberry Pi 2 Model B
×1
SparkFun Triple Axis Accelerometer and Gyro Breakout - MPU-6050
SparkFun Triple Axis Accelerometer and Gyro Breakout - MPU-6050
×1
Jumper wires (generic)
Jumper wires (generic)
×1

Software apps and online services

Windows 10 IoT Core
Microsoft Windows 10 IoT Core

Story

Read more

Schematics

Bread Board

Note: I am using is 5V GY-521 board, the Sparkfun version is 3.3V, so you will need to connect VCC to the 3.3V pin instead of 5V.

Code

Driver Code

C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Devices.Enumeration;
using Windows.Devices.I2c;
using Windows.Devices.Gpio;

namespace Mpu6050
{
    public class MpuSensorValue
    {
        public float AccelerationX { get; set; }
        public float AccelerationY { get; set; }
        public float AccelerationZ { get; set; }
        public float GyroX { get; set; }
        public float GyroY { get; set; }
        public float GyroZ { get; set; }
    }

    public class MpuSensorEventArgs : EventArgs
    {
        public byte Status { get; set; }
        public float SamplePeriod { get; set; }
        public MpuSensorValue [] Values { get; set; }
    }

    public partial class MPU6050 : IDisposable
    {
        public event EventHandler<MpuSensorEventArgs> SensorInterruptEvent;

        #region Constants

        public const byte ADDRESS = 0x68;
        private const byte PWR_MGMT_1 = 0x6B;
        private const byte SMPLRT_DIV = 0x19;
        private const byte CONFIG = 0x1A;
        private const byte GYRO_CONFIG = 0x1B;
        private const byte ACCEL_CONFIG = 0x1C;
        private const byte FIFO_EN = 0x23;
        private const byte INT_ENABLE = 0x38;
        private const byte INT_STATUS = 0x3A;
        private const byte USER_CTRL = 0x6A;
        private const byte FIFO_COUNT = 0x72;
        private const byte FIFO_R_W = 0x74;

        private const int SensorBytes = 12;

        #endregion

        private const Int32 INTERRUPT_PIN = 18;
        I2cDevice _mpu6050Device = null;
        private GpioController IoController;
        private GpioPin InterruptPin;

        #region 12c

        private byte ReadByte(byte regAddr)
        {
            byte[] buffer = new byte[1];
            buffer[0] = regAddr;
            byte[] value = new byte[1];
            _mpu6050Device.WriteRead(buffer, value);
            return value[0];
        }

        private byte[] ReadBytes(byte regAddr, int length)
        {
            byte[] values = new byte[length];
            byte[] buffer = new byte[1];
            buffer[0] = regAddr;
            _mpu6050Device.WriteRead(buffer, values);
            return values;
        }

        public ushort ReadWord(byte address)
        {
            byte[] buffer = ReadBytes(FIFO_COUNT, 2);
            return (ushort)(((int)buffer[0] << 8) | (int)buffer[1]);
        }

        void WriteByte(byte regAddr, byte data)
        {
            byte[] buffer = new byte[2];
            buffer[0] = regAddr;
            buffer[1] = data;
            _mpu6050Device.Write(buffer);
        }

        void writeBytes(byte regAddr, byte[] values)
        {
            byte[] buffer = new byte[1 + values.Length];
            buffer[0] = regAddr;
            Array.Copy(values, 0, buffer, 1, values.Length);
            _mpu6050Device.Write(buffer);
        }

        #endregion

        public async void InitHardware()
        {
            try
            {
                IoController = GpioController.GetDefault();
                InterruptPin = IoController.OpenPin(INTERRUPT_PIN);
                InterruptPin.Write(GpioPinValue.Low);
                InterruptPin.SetDriveMode(GpioPinDriveMode.Input);
                InterruptPin.ValueChanged += Interrupt;

                string aqs = I2cDevice.GetDeviceSelector();
                DeviceInformationCollection collection = await DeviceInformation.FindAllAsync(aqs);

                I2cConnectionSettings settings = new I2cConnectionSettings(ADDRESS);
                settings.BusSpeed = I2cBusSpeed.FastMode; // 400kHz clock
                settings.SharingMode = I2cSharingMode.Exclusive;
                _mpu6050Device = await I2cDevice.FromIdAsync(collection[0].Id, settings);

                await Task.Delay(3); // wait power up sequence

                WriteByte(PWR_MGMT_1, 0x80);// reset the device
                await Task.Delay(100);
                WriteByte(PWR_MGMT_1, 0x2);
                WriteByte(USER_CTRL, 0x04); //reset fifo

                WriteByte(PWR_MGMT_1, 1); // clock source = gyro x
                WriteByte(GYRO_CONFIG, 0); // +/- 250 degrees sec
                WriteByte(ACCEL_CONFIG, 0); // +/- 2g

                WriteByte(CONFIG, 1); // 184 Hz, 2ms delay
                WriteByte(SMPLRT_DIV, 19);  // set rate 50Hz
                WriteByte(FIFO_EN, 0x78); // enable accel and gyro to read into fifo
                WriteByte(USER_CTRL, 0x40); // reset and enable fifo
                WriteByte(INT_ENABLE, 0x1);
            }
            catch (Exception ex)
            {
                string error = ex.ToString();
            }
        }

        private void Interrupt(GpioPin sender, GpioPinValueChangedEventArgs args)
        {
            if (_mpu6050Device != null)
            {
                int interrupt_status = ReadByte(INT_STATUS);
                if ((interrupt_status & 0x10) != 0)
                {
                    WriteByte(USER_CTRL, 0x44); // reset and enable fifo
                }
                if ((interrupt_status & 0x1) != 0)
                {
                    MpuSensorEventArgs ea = new MpuSensorEventArgs();
                    ea.Status = (byte)interrupt_status;
                    ea.SamplePeriod = 0.02f;
                    List<MpuSensorValue> l = new List<MpuSensorValue>();

                    int count = ReadWord(FIFO_COUNT);

                    while (count >= SensorBytes)
                    {
                        byte[] data = ReadBytes(FIFO_R_W, (byte)SensorBytes);
                        count -= SensorBytes;

                        short xa = (short)((int)data[0] << 8 | (int)data[1]);
                        short ya = (short)((int)data[2] << 8 | (int)data[3]);
                        short za = (short)((int)data[4] << 8 | (int)data[5]);

                        short xg = (short)((int)data[6] << 8 | (int)data[7]);
                        short yg = (short)((int)data[8] << 8 | (int)data[9]);
                        short zg = (short)((int)data[10] << 8 | (int)data[11]);

                        MpuSensorValue sv = new MpuSensorValue();
                        sv.AccelerationX = (float)xa / (float)16384;
                        sv.AccelerationY = (float)ya / (float)16384;
                        sv.AccelerationZ = (float)za / (float)16384;
                        sv.GyroX = (float)xg / (float)131;
                        sv.GyroY = (float)yg / (float)131;
                        sv.GyroZ = (float)zg / (float)131;
                        l.Add(sv);
                    }
                    ea.Values = l.ToArray();

                    if (SensorInterruptEvent != null)
                    {
                        if (ea.Values.Length > 0)
                        {
                            SensorInterruptEvent(this, ea);
                        }
                    }
                }
            }
        }

        #region IDisposable Support
        private bool disposedValue = false; // To detect redundant calls

        protected virtual void Dispose(bool disposing)
        {
            if (!disposedValue)
            {
                InterruptPin.Dispose();
                if (_mpu6050Device != null)
                {
                    _mpu6050Device.Dispose();
                    _mpu6050Device = null;
                }
                disposedValue = true;

            }
        }

        ~MPU6050()
        {
            // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
            Dispose(false);
        }

        // This code added to correctly implement the disposable pattern.
        public void Dispose()
        {
            // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
            Dispose(true);
            GC.SuppressFinalize(this);
        }
        #endregion

    }
}

main code

C#
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Core;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace Mpu6050
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        MPU6050 _mpu6050 = new MPU6050();
        int _interruptCount = 0;
        DateTime _startTime;

        public MainPage()
        {
            this.InitializeComponent();
            _mpu6050.InitHardware();
            _mpu6050.SensorInterruptEvent += _mpu6050_SensorInterruptEvent;
            _startTime = DateTime.Now;
        }

        private void _mpu6050_SensorInterruptEvent(object sender, MpuSensorEventArgs e)
        {
            var task = Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                _interruptCount += e.Values.Length;
                float samples_per_second = (float)_interruptCount / (float)((DateTime.Now - _startTime).Seconds);
                textBoxStatus.Text = String.Format("{0} {1} {2}", e.Status, e.SamplePeriod, samples_per_second);
                textBoxAccel.Text = String.Format("{0}, {1}, {2}", e.Values[0].AccelerationX, e.Values[0].AccelerationY, e.Values[0].AccelerationZ);
                textBoxGyro.Text = String.Format("{0}, {1}, {2}", e.Values[0].GyroX, e.Values[0].GyroY, e.Values[0].GyroZ);
            });
        }

        private void button_Click(object sender, RoutedEventArgs e)
        {
            _mpu6050.Dispose();
            Application.Current.Exit();
        }
    }
}

Credits

Graham Chow

Graham Chow

14 projects • 78 followers
I'm a software developer on a long sabbatical. I've had wide experience from banking to underwater military sonar systems.

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