zephyr/samples/sensor/dht
Torsten Rasmussen 407b49b35c cmake: use find_package to locate Zephyr
Using find_package to locate Zephyr.

Old behavior was to use $ENV{ZEPHYR_BASE} for inclusion of boiler plate
code.

Whenever an automatic run of CMake happend by the build system / IDE
then it was required that ZEPHYR_BASE was defined.
Using ZEPHYR_BASE only to locate the Zephyr package allows CMake to
cache the base variable and thus allowing subsequent invocation even
if ZEPHYR_BASE is not set in the environment.

It also removes the risk of strange build results if a user switchs
between different Zephyr based project folders and forgetting to reset
ZEPHYR_BASE before running ninja / make.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-03-27 16:23:46 +01:00
..
boards
src
CMakeLists.txt cmake: use find_package to locate Zephyr 2020-03-27 16:23:46 +01:00
prj.conf
README.rst
sample.yaml

.. _dht:

DHT: Aosong DHT Digital-output Humidity and Temperature Sensor
##############################################################

Description
***********

This sample application periodically (0.5 Hz) measures the ambient
temperature and humidity. The result is written to the console.

Wiring
*******

This sample uses an external breakout for the sensor.  A devicetree
overlay must be provided to identify the sensor variant and the GPIO
used to control the sensor.

Building and Running
********************

After providing a devicetree overlay that specifies the sensor location,
build this sample app using:

.. zephyr-app-commands::
   :zephyr-app: samples/sensor/dht
   :board: nrf52_pca10040
   :goals: build flash

Sample Output
=============

.. code-block:: console

   *** Booting Zephyr OS build zephyr-v2.1.0-329-g38418b26c4cc  ***
   [0:00:00.027]: 20.0 Cel ; 48.7 %RH
   [0:00:02.053]: 19.8 Cel ; 48.7 %RH
   [0:00:04.079]: 20.0 Cel ; 48.7 %RH
   [0:00:06.105]: 19.8 Cel ; 48.7 %RH
   [0:00:08.130]: 20.0 Cel ; 48.8 %RH
   [0:00:10.156]: 20.1 Cel ; 48.8 %RH
   [0:00:12.182]: 19.7 Cel ; 48.7 %RH
   [0:00:14.207]: 20.0 Cel ; 48.8 %RH

<repeats endlessly>