zephyr/samples/sensor/max30101
Keith Packard 0b90fd5adf samples, tests, boards: Switch main return type from void to int
As both C and C++ standards require applications running under an OS to
return 'int', adapt that for Zephyr to align with those standard. This also
eliminates errors when building with clang when not using -ffreestanding,
and reduces the need for compiler flags to silence warnings for both clang
and gcc.

Most of these changes were automated using coccinelle with the following
script:

@@
@@
- void
+ int
main(...) {
	...
-	return;
+	return 0;
	...
}

Approximately 40 files had to be edited by hand as coccinelle was unable to
fix them.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-14 07:49:41 +09:00
..
boards gpio: mcux: Convert convert to DT_INST defines 2020-04-23 17:07:41 -05:00
src samples, tests, boards: Switch main return type from void to int 2023-04-14 07:49:41 +09:00
CMakeLists.txt cmake: increase minimal required version to 3.20.0 2021-08-20 09:47:34 +02:00
prj.conf sensors: Remove unnecessary Kconfig setting of sensors 2022-07-25 15:18:56 +02:00
README.rst doc: fix broken file and zephyr-app refs 2019-10-08 15:42:32 -05:00
sample.yaml samples: sensor: add integration_platforms 2021-04-09 06:50:47 -04:00

.. _max30101:

MAX30101 Heart Rate Sensor
##########################

Overview
********

A sensor application that demonstrates how to poll data from the max30101 heart
rate sensor.

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

This project configures the max30101 sensor on the :ref:`hexiwear_k64` board to
enable the green LED and measure the reflected light with a photodiode. The raw
ADC data prints to the console. Further processing (not included in this
sample) is required to extract a heart rate signal from the light measurement.

.. zephyr-app-commands::
   :zephyr-app: samples/sensor/max30101
   :board: hexiwear_k64
   :goals: build
   :compact:

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

.. code-block:: console

   GREEN=5731
   GREEN=5750
   GREEN=5748
   GREEN=5741
   GREEN=5735
   GREEN=5737
   GREEN=5736
   GREEN=5748

<repeats endlessly>