Meadow.Foundation.Sensors.Atmospheric.Si70xx
Si70xx | |
---|---|
Status | |
Source code | GitHub |
Datasheet(s) | GitHub |
NuGet package |
The SI70xx is a humidity and temperature sensor controlled via I2C.
- ± 3% RH (max)
- 0–80% RH
- High Accuracy Temperature Sensor ±0.4 °C
- –10 to 85 °C
- 0 to 100% RH operating range
- Up to –40 to +125 °C operating range
- Wide operating voltage (1.9 to 3.6 V)
- Low Power Consumption
- 150 µA active current
- 60 nA standby current
Purchasing
The Si7021 is available on a breakout board from the the following suppliers:
Code Example
Si70xx? sensor;
public override Task Initialize()
{
Resolver.Log.Info("Initializing...");
sensor = new Si70xx(Device.CreateI2cBus());
var consumer = Si70xx.CreateObserver(
handler: result =>
{
Resolver.Log.Info($"Observer: Temp changed by threshold; new temp: {result.New.Temperature?.Celsius:N2}C, old: {result.Old?.Temperature?.Celsius:N2}C");
},
filter: result =>
{
if (result.Old?.Temperature is { } oldTemp &&
result.Old?.Humidity is { } oldHumidity &&
result.New.Temperature is { } newTemp &&
result.New.Humidity is { } newHumidity)
{
return ((newTemp - oldTemp).Abs().Celsius > 0.5 &&
(newHumidity - oldHumidity).Percent > 0.05);
}
return false;
}
);
sensor.Subscribe(consumer);
sensor.Updated += (sender, result) =>
{
Resolver.Log.Info($" Temperature: {result.New.Temperature?.Celsius:F1}C");
Resolver.Log.Info($" Relative Humidity: {result.New.Humidity:F1}%");
};
return Task.CompletedTask;
}
public override async Task Run()
{
if (sensor == null) { return; }
var result = await sensor.Read();
Resolver.Log.Info("Initial Readings:");
Resolver.Log.Info($" Temperature: {result.Temperature?.Celsius:F1}C");
Resolver.Log.Info($" Relative Humidity: {result.Humidity:F1}%");
sensor.StartUpdating(TimeSpan.FromSeconds(1));
}
Sample project(s) available on GitHub
Wiring Example
To wire a Si7021 to your Meadow board, connect the following:
Si7021 | Meadow Pin |
---|---|
GND | GND |
SCL | D08 (SCL) |
SDA | D07 (SDA) |
VCC | 3V3 |
It should look like the following diagram:
Class Si70xx
Provide access to the Si70xx series (Si7020, Si7021, and Si7030) temperature and humidity sensors
Assembly: Si70xx.dll
View Source
public class Si70xx : ByteCommsSensorBase<(Temperature? Temperature, RelativeHumidity? Humidity)>, IObservable<IChangeResult<(Temperature? Temperature, RelativeHumidity? Humidity)>>, ISamplingSensor<(Temperature? Temperature, RelativeHumidity? Humidity)>, ISensor<(Temperature? Temperature, RelativeHumidity? Humidity)>, IDisposable, ITemperatureSensor, ISamplingSensor<Temperature>, ISensor<Temperature>, IHumiditySensor, ISamplingSensor<RelativeHumidity>, ISensor<RelativeHumidity>, ISensor, ISamplingSensor, II2cPeripheral
Inheritance: System.Object
-> Meadow.Foundation.ObservableBase<UNIT>
Implements:
Expand
System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>>>
, Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>>
, Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>>
, System.IDisposable
, Meadow.Peripherals.Sensors.ITemperatureSensor
, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Temperature>
, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Temperature>
, Meadow.Peripherals.Sensors.Atmospheric.IHumiditySensor
, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.RelativeHumidity>
, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.RelativeHumidity>
, Meadow.Peripherals.Sensors.ISensor
, Meadow.Peripherals.Sensors.ISamplingSensor
, Meadow.Hardware.II2cPeripheral
Properties
Temperature
The temperature from the last reading
View Source
public Temperature? Temperature { get; }
Humidity
The humidity, in percent relative humidity, from the last reading
View Source
public RelativeHumidity? Humidity { get; }
SerialNumber
Serial number of the device
View Source
public ulong SerialNumber { get; }
SensorType
Device type as extracted from the serial number
View Source
public Si70xx.DeviceType SensorType { get; }
FirmwareRevision
Firmware revision of the sensor
View Source
public byte FirmwareRevision { get; }
DefaultI2cAddress
The default I2C address for the peripheral
View Source
public byte DefaultI2cAddress { get; }
Methods
Reset()
Reset the sensor
View Source
protected void Reset()
Initialize()
Initialize the sensor
View Source
protected void Initialize()
ReadSensor()
Reads data from the sensor
View Source
protected override Task<(Temperature? Temperature, RelativeHumidity? Humidity)> ReadSensor()
Returns
System.Threading.Tasks.Task<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>>
: The latest sensor reading### RaiseEventsAndNotify(IChangeResult<(Temperature? Temperature, RelativeHumidity? Humidity)>)
Inheritance-safe way to raise events and notify observers.
View Source
protected override void RaiseEventsAndNotify(IChangeResult<(Temperature? Temperature, RelativeHumidity? Humidity)> changeResult)
Parameters
Type | Name |
---|---|
Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>> | changeResult |
Heater(bool)
Turn the heater on or off
View Source
public void Heater(bool onOrOff)
Parameters
Type | Name | Description |
---|---|---|
System.Boolean | onOrOff | Heater status, true = turn heater on, false = turn heater off. |
Implements
System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>>>
Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>>
Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.RelativeHumidity>>>
System.IDisposable
Meadow.Peripherals.Sensors.ITemperatureSensor
Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Temperature>
Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Temperature>
Meadow.Peripherals.Sensors.Atmospheric.IHumiditySensor
Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.RelativeHumidity>
Meadow.Peripherals.Sensors.ISensor<Meadow.Units.RelativeHumidity>
Meadow.Peripherals.Sensors.ISensor
Meadow.Peripherals.Sensors.ISamplingSensor
Meadow.Hardware.II2cPeripheral