uBit.thermometer¶

Overview¶

MicroBitThermometer provides access to the surface temperature of the nrf51822. The temperature reading therefore is not representative of the ambient temperature, but rather the temperature relative to the surface temperature of the chip.

However, we can make it representative of the ambient temperature in software through "calibrating" the thermometer.

Calibration is very simple, and is calculated by giving the current temperature to the setCalibration() member function. From the temperature, an offset is calculated, and is subsequently used to offset future temperature readings.

Real time updates¶

When using the standard uBit presentation, the thermometer is continuously updated in the background using an idle thread (after it is first used), which is executed whenever the micro:bit has no other tasks to perform.

If there is no scheduler running, the values are synchronously read on getTemperature() calls. Additionally, if you would like to drive thermometer updates manually updateSample() can be used.

Message Bus ID¶

Constant	Value
MICROBIT_ID_THERMOMETER	28

Message Bus Events¶

Constant	Value
MICROBIT_THERMOMETER_EVT_UPDATE	1

API¶

Constructor¶

MicroBitThermometer(

MicroBitStorage &

_storage)¶

Description¶

Constructor. Create new MicroBitThermometer that gives an indication of the current temperature.

Parameters¶

MicroBitStorage &

_storage - an instance of MicroBitStorage used to persist temperature offset data

Example¶

 MicroBitStorage storage; 
 MicroBitThermometer thermometer(storage); 

MicroBitThermometer(

MicroBitStorage &

_storage,

uint16_t

id)¶

Description¶

Constructor. Create new MicroBitThermometer that gives an indication of the current temperature.

Parameters¶

MicroBitStorage &

_storage - an instance of MicroBitStorage used to persist temperature offset data

uint16_t

id - the unique EventModel id of this component. Defaults to MICROBIT_ID_THERMOMETER.

Example¶

 MicroBitStorage storage; 
 MicroBitThermometer thermometer(storage); 

MicroBitThermometer()¶

Description¶

Constructor. Create new MicroBitThermometer that gives an indication of the current temperature.

Example¶

 MicroBitThermometer thermometer; 

MicroBitThermometer(

uint16_t

id)¶

Description¶

Constructor. Create new MicroBitThermometer that gives an indication of the current temperature.

Parameters¶

uint16_t

id - the unique EventModel id of this component. Defaults to MICROBIT_ID_THERMOMETER.

Example¶

 MicroBitThermometer thermometer; 

setPeriod¶

void

setPeriod

(

int

period)¶

Description¶

Set the sample rate at which the temperatureis read (in ms).

The default sample period is 1 second.

Parameters¶

int

period - the requested time between samples, in milliseconds.

getPeriod¶

int

getPeriod

()¶

Description¶

Reads the currently configured sample rate of the thermometer.

Returns¶

The time between samples, in milliseconds.

setOffset¶

int

setOffset

(

int

offset)¶

Description¶

Set the value that is used to offset the raw silicon temperature.

Parameters¶

int

offset - the offset for the silicon temperature

Returns¶

MICROBIT_OK on success

getOffset¶

int

getOffset

()¶

Description¶

Retreive the value that is used to offset the raw silicon temperature.

Returns¶

the current offset.

setCalibration¶

int

setCalibration

(

int

calibrationTemp)¶

Description¶

This member function fetches the raw silicon temperature, and calculates the value used to offset the raw silicon temperature based on a given temperature.

Parameters¶

int

calibrationTemp - the temperature used to calculate the raw silicon temperature offset.

Returns¶

MICROBIT_OK on success

getTemperature¶

int

getTemperature

()¶

Description¶

Gets the current temperature of the microbit.

Returns¶

the current temperature, in degrees celsius.

Example¶

 thermometer.getTemperature(); 

updateSample¶

int

updateSample

()¶

Description¶

Updates the temperature sample of this instance of MicroBitThermometer only if isSampleNeeded() indicates that an update is required.

This call also will add the thermometer to fiber components to receive periodic callbacks.

Returns¶

MICROBIT_OK on success.

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