.. zephyr:code-sample:: thermometer
:name: Thermometer
:relevant-api: sensor_interface
Get ambient temperature data from a temperature sensor and get alerts when temperature drifts
above a threshold. (polling & trigger mode).
Overview
********
This sample application periodically measures the ambient temperature
at 1Hz. The result is written to the console.
Wiring
*******
VDD pin should be connected to 2.3V to 5.5V
GND pin connected to 0V
VOUT pin connected to the ADC input pin.
.. _`MCP970X Sensor`: http://ww1.microchip.com/downloads/en/devicedoc/20001942g.pdf
An overlay is provided for the nrf52840dk/nrf52840 board with the
sensor connected to pin AIN7.
Building and Running
********************
To build for the nrf52840dk/nrf52840 board use:
.. zephyr-app-commands::
:zephyr-app: samples/sensor/thermometer
:board: nrf52840dk/nrf52840
:goals: build flash
:compact:
To build for other boards and ambient temperature sensors, enable the sensor
node that supports ``SENSOR_CHAN_AMBIENT_TEMP`` and use an overlay to create an
alias named ``ambient-temp0`` to link to the node. See the overlay used for the
``nrf52840dk/nrf52840`` board within this sample:
``boards/nrf52840dk_nrf52840.overlay``
Temperature Alert
=================
If the attached sensor supports alerts when the temperature drifts above or
below a threshold, the sample will enable the sensor's trigger functionality.
This will require the sensor's TRIGGER KConfig setting to be enabled. An
example of this setup is provided for the ``frdm_k22f`` board, using
``boards/frdm_k22f.conf``.
Sample Output
=============
.. code-block:: console
*** Booting Zephyr OS build zephyr-v3.3.0-2354-gb4f4bd1f1c22 ***
Thermometer Example (arm)
Temperature device is 0x525c, name is tcn75a@48
Set temperature lower limit to 25.5°C
Set temperature upper limit to 26.5°C
Enabled sensor threshold triggers
Temperature is 25.0°C
Temperature is 25.0°C
Temperature is 25.0°C
Temperature is 25.0°C
Temperature is 25.5°C
Temperature above threshold: 26.5°C
Temperature is 26.5°C
9fe959857a