Remarks
| Adxl345 | |
|---|---|
| Status |  |
| Source code | GitHub |
| Datasheet(s) | GitHub |
| NuGet package |  |
The ADXL345 is a small, low power, triple axis acceleration sensor capable of measuring up to +/-16g with a resolution of 13-bits.
The ADXL345 is controlled via I2C.
The ADXL345 can operating in interrupt and polling mode. Polling applications are responsible for determining when a sensor is read. Interrupt applications will be notified when the sensor reading changes by + / - a threshold value.
Purchasing
The ADXL345 is available on a small breakout board:
Code Example
Adxl345 sensor;
public MeadowApp()
{
Console.WriteLine("Initializing");
sensor = new Adxl345(Device.CreateI2cBus());
sensor.SetPowerState(false, false, true, false, Adxl345.Frequencies.TwoHz);
// classical .NET events can also be used:
sensor.Updated += (sender, result) =>
{
Console.WriteLine($"Accel: [X:{result.New.X.MetersPerSecondSquared:N2}," +
$"Y:{result.New.Y.MetersPerSecondSquared:N2}," +
$"Z:{result.New.Z.MetersPerSecondSquared:N2} (m/s^2)]");
};
//==== one-off read
ReadConditions().Wait();
// start updating
sensor.StartUpdating(TimeSpan.FromMilliseconds(500));
}
protected async Task ReadConditions()
{
var result = await sensor.Read();
Console.WriteLine("Initial Readings:");
Console.WriteLine($"Accel: [X:{result.X.MetersPerSecondSquared:N2}," +
$"Y:{result.Y.MetersPerSecondSquared:N2}," +
$"Z:{result.Z.MetersPerSecondSquared:N2} (m/s^2)]");
}
Sample project(s) available on GitHub
Wiring Example
Syntax
public class Adxl345 : ByteCommsSensorBase<Acceleration3D>, ISamplingSensor<Acceleration3D>, ISamplingSensor<Acceleration3D>, IDisposable, IAccelerometerConstructors
Adxl345(II2cBus, Adxl345.Addresses)
Create a new instance of the ADXL345 communicating over the I2C interface.
Declaration
public Adxl345(II2cBus i2cBus, Adxl345.Addresses address = default(Adxl345.Addresses))Parameters
| Type | Name | Description |
|---|---|---|
| II2cBus | i2cBus | I2C bus |
| Adxl345.Addresses | address | Address of the I2C sensor |
Adxl345(II2cBus, Byte)
Create a new instance of the ADXL345 communicating over the I2C interface.
Declaration
public Adxl345(II2cBus i2cBus, byte address)Parameters
| Type | Name | Description |
|---|---|---|
| II2cBus | i2cBus | I2C bus |
| System.Byte | address | Address of the I2C sensor |
Fields
MinimumPollingPeriod
Minimum value that can be used for the update interval when the sensor is being configured to generate interrupts.
Declaration
public const ushort MinimumPollingPeriod = nullField Value
| Type | Description |
|---|---|
| System.UInt16 |
Properties
Acceleration3D
Current acceleration
Declaration
public Acceleration3D? Acceleration3D { get; }Property Value
| Type | Description |
|---|---|
| System.Nullable<Acceleration3D> |
OffsetX
Values stored in this register are automatically added to the X reading.
Declaration
public sbyte OffsetX { get; set; }Property Value
| Type | Description |
|---|---|
| System.SByte |
Remarks
Scale factor is 15.6 mg/LSB so 0x7f represents an offset of 2g.
OffsetY
Values stored in this register are automatically added to the Y reading.
Declaration
public sbyte OffsetY { get; set; }Property Value
| Type | Description |
|---|---|
| System.SByte |
Remarks
Scale factor is 15.6 mg/LSB so 0x7f represents an offset of 2g.
OffsetZ
Values stored in this register are automatically added to the Z reading.
Declaration
public sbyte OffsetZ { get; set; }Property Value
| Type | Description |
|---|---|
| System.SByte |
Remarks
Scale factor is 15.6 mg/LSB so 0x7f represents an offset of 2g.
Methods
DisplayRegisters()
Dump the registers to the debug output stream.
Declaration
public void DisplayRegisters()RaiseEventsAndNotify(IChangeResult<Acceleration3D>)
Raise changed event for subscribers
Declaration
protected override void RaiseEventsAndNotify(IChangeResult<Acceleration3D> changeResult)Parameters
| Type | Name | Description |
|---|---|---|
| IChangeResult<Acceleration3D> | changeResult |
ReadSensor()
Read sensor
Declaration
protected override Task<Acceleration3D> ReadSensor()Returns
| Type | Description |
|---|---|
| Task<Acceleration3D> | Current acceleration |
Overrides
SetDataFormat(Boolean, Boolean, Boolean, Boolean, Adxl345.GForceRanges)
Configure the data format (see pages 26 and 27 of the data sheet).
Declaration
public void SetDataFormat(bool selfTest, bool spiMode, bool fullResolution, bool justification, Adxl345.GForceRanges range)Parameters
| Type | Name | Description |
|---|---|---|
| System.Boolean | selfTest | Put the device into self test mode when true. |
| System.Boolean | spiMode | Use 3-wire SPI (true) or 4-wire SPI (false). |
| System.Boolean | fullResolution | Set to full resolution (true) or 10-bit mode using the range determined by the range parameter (false). |
| System.Boolean | justification | Left-justified when true, right justified with sign extension when false. |
| Adxl345.GForceRanges | range | Set the range of the sensor to 2g, 4g, 8g or 16g |
Remarks
The range of the sensor is determined by the following table: 0: +/- 2g 1: +/- 4g 2: +/- 8g 3: +/ 16g
SetDataRate(Byte, Boolean)
Set the data rate and low power mode for the sensor.
Declaration
public void SetDataRate(byte dataRate, bool lowPower)Parameters
| Type | Name | Description |
|---|---|---|
| System.Byte | dataRate | Data rate for the sensor. |
| System.Boolean | lowPower | Setting this to true will enter low power mode (note measurement will encounter more noise in this mode). |
SetPowerState(Boolean, Boolean, Boolean, Boolean, Adxl345.Frequencies)
Set the PowerControl register (see pages 25 and 26 of the data sheet)
Declaration
public void SetPowerState(bool linkActivityAndInactivity, bool autoSleep, bool measuring, bool sleep, Adxl345.Frequencies frequency)Parameters
| Type | Name | Description |
|---|---|---|
| System.Boolean | linkActivityAndInactivity | Link the activity and inactivity events. |
| System.Boolean | autoSleep | Enable / disable auto sleep when the activity and inactivity are linked. |
| System.Boolean | measuring | Enable or disable measurements (turn on or off). |
| System.Boolean | sleep | Put the part to sleep (true) or run in normal more (false). |
| Adxl345.Frequencies | frequency | Frequency of measurements when the part is in sleep mode. |
Events
Acceleration3DUpdated
Event raised when acceleration changes
Declaration
public event EventHandler<IChangeResult<Acceleration3D>> Acceleration3DUpdatedEvent Type
| Type | Description |
|---|---|
| EventHandler<IChangeResult<Acceleration3D>> |