Protocol

MWPollable

Sensors natively incapable of continuous output, such as thermistors, can output “streamable” and loggable outputs with the help of onboard timers that fire at reasonable intervals. This protocol organizes the methods and properties for polling such sensors.

Declaration

protocol MWPollable : MWReadable

Overview

To start polling, use the .stream() or .log() operators. These are available on a Publisher whose output is a MetaWear, including:

These operators accept MWPollable instances constructed by autocompletion, such as humidity(oversampling:rate:), or directly, such as init(oversampling:rate:).

Direct construction may be useful for patterns where you persist user selected settings or organize arbitrarily large logging or streaming sessions. Our open-source MetaBase 5 app provides an example in ActionVM.swift of starting logging and streaming sessions with arbitrary mixes of MWPollable, MWStreamable, and MWLoggable sensors with merged outputs.

Unless you construct your own sensor wrappers, this protocol’s details are unlikely to be important to you.

Topics

Instance Properties

var pollingRate: MWFrequency
Rate at which an event fires to read the sensor’s signal.

Required.

var signalName: MWNamedSignal
Identifier for downloadable signal when exporting an MWDataTable.

Required.

Instance Methods

func pollCleanup(board: MWBoard)
Called after unsubscribing to the event signal.

Required. Default implementation provided.

func pollConfigure(board: MWBoard)
Commands to customize the “stream”

Required. Default implementation provided.

func pollSensorSignal(board: MWBoard) throws -> MWDataSignal?
Obtains a reference to the module’s “streamable” signal.

Required. Default implementation provided.

Type Methods

static func humidity(oversampling: MWHumidity.Oversampling, rate: MWFrequency) -> Self
Available when Self is MWHumidity.
static func thermometer(rate: MWFrequency, type: MWThermometer.Source, board: MWBoard) throws -> Self
Thermistor reports degrees Celsius.
Available when Self is MWThermometer.

Relationships

Inherits From

Conforming Types

See Also

Interact

protocol MWCommand
Issues a command, such as recording a macro or resetting to factory defaults.
protocol MWCommandWithResponse
Issues a command that returns a value.
protocol MWLoggable
Sensors that can log data to onboard storage adhere to this protocol to configure, start, stop, and download the logger.
protocol MWReadable
For signals that can only be read once Sensors natively incapable of continuous output, such as thermistors, adopt this protocol to organize configuring, reading, and closing a sensor’s data signal.
protocol MWReadableMerged
A read command that coalesces multiple operations into one output.
protocol MWStreamable
Sensors that can stream data at about 100 to 120 Hz adhere to this protocol to configure, start, and stop a data signal.
struct MWFrequency
Specify event frequencies in Hz or millisecond periods between events