mirror of
https://github.com/esphome/esphome-docs.git
synced 2024-08-16 21:53:10 +02:00
377 lines
14 KiB
ReStructuredText
377 lines
14 KiB
ReStructuredText
Custom Sensor Component
|
|
=======================
|
|
|
|
.. warning::
|
|
|
|
While I do try to keep the esphomeyaml configuration options as stable as possible
|
|
and back-port them, the esphomelib API is less stable. If something in the APIs needs
|
|
to be changed in order for something else to work, I will do so.
|
|
|
|
So, you just set up esphomelib for your ESP32/ESP8266, but sadly esphomelib is missing a sensor integration
|
|
you'd really like to have 😕. It's pretty much impossible to support every single sensor, as there are simply too many.
|
|
That's why esphomelib has a really simple API for you to create your own **custom sensors** 🎉
|
|
|
|
In this guide, we will go through creating a custom sensor component for the
|
|
`BMP180 <https://www.adafruit.com/product/1603>`__ pressure sensor (we will only do the pressure part,
|
|
temperature is more or less the same). During this guide, you will learn how to 1. define a custom sensor
|
|
esphomelib can use 2. go over how to register the sensor so that it will be shown inside Home Assistant and
|
|
3. leverage an existing arduino library for the BMP180 with esphomelib.
|
|
|
|
.. note::
|
|
|
|
Since the creation of this guide, the BMP180 has been officially supported by the :doc:`BMP085 component
|
|
<bmp085>`. The code still applies though.
|
|
|
|
This guide will require at least a bit of knowledge of C++, so be prepared for that. If you have any problems,
|
|
I'm here to help :) https://discord.gg/KhAMKrd
|
|
|
|
Step 1: Custom Sensor Definition
|
|
--------------------------------
|
|
|
|
At this point, you might have a main source file like this:
|
|
|
|
.. code:: cpp
|
|
|
|
// ...
|
|
using namespace esphomelib;
|
|
|
|
void setup() {
|
|
// ===== DO NOT EDIT ANYTHING BELOW THIS LINE =====
|
|
// ========== AUTO GENERATED CODE BEGIN ===========
|
|
App.set_name("livingroom");
|
|
App.init_log();
|
|
// ...
|
|
// =========== AUTO GENERATED CODE END ============
|
|
// ========= YOU CAN EDIT AFTER THIS LINE =========
|
|
App.setup();
|
|
}
|
|
|
|
void loop() {
|
|
App.loop();
|
|
}
|
|
|
|
To create your own custom sensor, you just have define a C++ class that extends ``Component`` and ``Sensor`` like this:
|
|
|
|
.. code:: cpp
|
|
|
|
using namespace esphomelib;
|
|
|
|
class CustomSensor : public Component, public sensor::Sensor {
|
|
public:
|
|
CustomSensor(const std::string &name) : Sensor(name) {}
|
|
|
|
void setup() override {
|
|
// This will be called by App.setup()
|
|
}
|
|
void loop() override {
|
|
// This will be called by App.loop()
|
|
}
|
|
};
|
|
|
|
void setup() {
|
|
// ...
|
|
|
|
Additionally, you need to change an internal flag that changes how esphomeyaml compiles files.
|
|
The only downside is that this will make build times *a tiny bit* slower:
|
|
|
|
.. code:: yaml
|
|
|
|
esphomeyaml:
|
|
# ...
|
|
use_custom_code: True
|
|
|
|
You've just created your first esphomelib sensor 🎉. It doesn't do very much right now and is never registered,
|
|
but it's a first step.
|
|
|
|
Let's now take a look at how a sensor works in esphomelib: A sensor is some hardware device (like a BMP180)
|
|
that sends out new values like temperatures.
|
|
|
|
Like any Component in esphomelib, if it's registered in the Application, ``setup()`` will be called for you when
|
|
``App.setup()`` is run. ``setup()`` is also the place where you should do hardware initialization like setting
|
|
``pinMode()``. Next, every time ``App.loop()`` is called, your component will also receive a ``loop()`` call.
|
|
This is the place where you should do stuff like querying a sensor for a new value like you might be used
|
|
to do in an Arduino sketch.
|
|
|
|
Let's now also take a closer look at this line, which you might not be too used to when writing pure C code:
|
|
|
|
.. code:: cpp
|
|
|
|
class CustomSensor : public Component, public sensor::Sensor {
|
|
|
|
What this line is essentially saying is that we're defining our own class that's called ``CustomSensor``
|
|
which is also a subclass of ``Component`` and ``Sensor`` (in the namespace ``sensor::``).
|
|
``Component`` is there so that we can register it in our application and so that we will receive ``setup()``
|
|
and ``loop()`` calls. We're also inheriting from the ``Sensor`` class so that our custom sensor can send sensor
|
|
values to the frontend (like MQTT).
|
|
|
|
As most sensors really just setup some pins and then check the sensor every x seconds,
|
|
there's another abstraction that we'll use to simplify our code: ``PollingSensorComponent``.
|
|
|
|
.. code:: cpp
|
|
|
|
class CustomSensor : public sensor::PollingSensorComponent {
|
|
public:
|
|
CustomSensor(const std::string &name, uint32_t update_interval)
|
|
: sensor::PollingSensorComponent(name, update_interval) {}
|
|
|
|
void setup() override {
|
|
// This will be called by App.setup()
|
|
}
|
|
void update() override {
|
|
// This will be called every `update_interval` milliseconds.
|
|
}
|
|
};
|
|
|
|
What ``PollingSensorComponent`` (and ``PollingComponent``) does is essentially
|
|
just replace the ``loop()`` method and will call ``update()`` instead every ``update_interval`` milliseconds.
|
|
Because with most sensors, you really don't need to get the latest values with every single ``loop()``
|
|
call (which can be called many times per second). If we forward the ``update_interval`` in our *constructor*
|
|
(line 3), ``PollingSensorComponent`` will call ``update()`` for us every ``update_interval``
|
|
milliseconds, so that we don't have to do time checking ourselves.
|
|
You don't really need to know about C++ constructors for now, but I would definitely recommend reading up on them
|
|
in the Internet.
|
|
|
|
Let's also now make our sensor actually *output* values (42 for now):
|
|
|
|
.. code:: cpp
|
|
|
|
// class CustomSensor ...
|
|
// ... previous code
|
|
void update() override {
|
|
publish_state(42.0); // 42°C
|
|
}
|
|
|
|
std::string unit_of_measurement() override { return "°C"; }
|
|
int8_t accuracy_decimals() override { return 2; } // 2 decimal places of accuracy.
|
|
};
|
|
|
|
Every time ``update`` is called we will now **push** a new value to the frontend.
|
|
The front-end will then relay those values to MQTT and finally to Home Assistant.
|
|
Additionally, we created a function that tells the sensor what unit of measurement the
|
|
value is in, this is not strictly required and only used for a nice output in Home Assistant.
|
|
|
|
Step 2: Registering the custom sensor
|
|
-------------------------------------
|
|
|
|
Now we have our Custom Sensor set up, but unfortunately it doesn't do much right now.
|
|
Actually ... it does nothing because it's never registered in the App,
|
|
so esphomelib can't know about it. Let's change that.
|
|
|
|
In your global ``setup()`` method, after you've setup all other components, do the following:
|
|
|
|
.. code:: cpp
|
|
|
|
void setup() {
|
|
// ...
|
|
// =========== AUTO GENERATED CODE END ============
|
|
// ========= YOU CAN EDIT AFTER THIS LINE =========
|
|
|
|
auto *custom_sensor = new CustomSensor("My Custom Sensor", 5000); // update every 5000ms or every 5 seconds.
|
|
App.register_component(custom_sensor);
|
|
App.register_sensor(custom_sensor);
|
|
|
|
App.setup();
|
|
}
|
|
|
|
If you have Home Assistant MQTT discovery setup, it will even automatically show up in the frontend 🎉
|
|
(with the entity id ``sensor.custom_sensor_example``)
|
|
|
|
.. figure:: images/custom-ui.png
|
|
:align: center
|
|
:width: 60%
|
|
|
|
Let's go through the code for registering our custom sensor. First, we're creating a new CustomSensor
|
|
instance with the update interval of 5000ms using the ``new`` C++ syntax (important!) and assigning it to a
|
|
variable ``custom_sensor`` (using C++11 ``auto`` type specifier to make it simpler).
|
|
|
|
.. code:: cpp
|
|
|
|
auto *custom_sensor = new CustomSensor(5000);
|
|
|
|
Next, we *register* the component in esphomelib's Application instance so that it can call the component's
|
|
``setup()`` and ``loop()``.
|
|
|
|
.. code:: cpp
|
|
|
|
App.register_component(custom_sensor);
|
|
|
|
// you could also write this, it's a bit shorter and works the same way.
|
|
// auto *custom_sensor = App.register_component(new CustomSensor(5000));
|
|
|
|
App.register_sensor(custom_sensor);
|
|
|
|
Lastly, we're registering the *sensor* with ``register_sensor``, this will automatically set up a
|
|
bunch of callbacks so that it can publish state changes to MQTT when you call ``publish_new_value()``,
|
|
create automatic MQTT discovery messages and setup a moving average over the sensor values
|
|
(adjust these as you would with any other sensor).
|
|
|
|
Step 3: BMP180 support
|
|
----------------------
|
|
|
|
Let's finally make this custom sensor useful by adding the BMP180 aspect into it! A great feature of
|
|
esphomelib is that you can just use all existing arduino libraries, amazing right? Now for this example we'll
|
|
use the `Adafruit BMP085 Library <https://platformio.org/lib/show/525/Adafruit%20BMP085%20Library>`__
|
|
library by Adafruit.
|
|
|
|
First we'll need to add the library to our platformio dependencies. To do so, put the following in
|
|
the ``common`` section of your ``platformio.ini``:
|
|
|
|
.. code:: ini
|
|
|
|
[common]
|
|
lib_deps = Adafruit BMP085 Library
|
|
build_flags =
|
|
upload_flags =
|
|
|
|
Next, include the library at the top of you main sketch file (``<NODE_NAME>/src/main.cpp``):
|
|
|
|
.. code:: cpp
|
|
|
|
#include "esphomelib/application.h"
|
|
#include <Adafruit_BMP085.h>
|
|
|
|
using namespace esphomelib;
|
|
|
|
// ...
|
|
|
|
Then update our sensor for BMP180 support:
|
|
|
|
.. code:: cpp
|
|
|
|
// ...
|
|
|
|
class BMP180Sensor : public sensor::PollingSensorComponent {
|
|
public:
|
|
Adafruit_BMP085 bmp;
|
|
|
|
BMP180Sensor(const std::string &name, uint32_t update_interval)
|
|
: sensor::PollingSensorComponent(name, update_interval) {
|
|
|
|
}
|
|
|
|
void setup() override {
|
|
bmp.begin();
|
|
}
|
|
|
|
void update() override {
|
|
int pressure = bmp.readPressure(); // in Pa, or 1/100 hPa
|
|
publish_state(pressure / 100.0); // convert to hPa
|
|
}
|
|
|
|
std::string unit_of_measurement() override { return "hPa"; }
|
|
int8_t accuracy_decimals() override { return 2; } // 2 decimal places of accuracy.
|
|
};
|
|
|
|
void setup() {
|
|
// ...
|
|
|
|
auto *custom_sensor = new BMP180Sensor("My BMP180 sensor", 5000);
|
|
App.register_component(custom_sensor);
|
|
App.register_sensor(custom_sensor);
|
|
|
|
App.setup();
|
|
}
|
|
|
|
// ...
|
|
|
|
There's not too much going on there. First, we define the variable ``bmp`` of type ``Adafruit_BMP085``
|
|
inside our class as a class member. In ``setup()`` we initialize the library and in ``update()`` we read the
|
|
pressure and send it out to MQTT.
|
|
|
|
You've now successfully created your first custom sensor component 🎉 Happy coding!
|
|
|
|
Bonus: Sensors With Multiple Output Values
|
|
------------------------------------------
|
|
|
|
The ``PollingSensorComponent`` doesn't fit every use-case. Sometimes, (as with the BMP180),
|
|
a sensor can expose multiple values (temperature *and* pressure, for example).
|
|
|
|
Doing so in esphomelib is a bit more difficult. Basically, we will have to change our sensor
|
|
model to have *one component* that reads out the values and *one sensor class* for each value
|
|
we want to expose.
|
|
|
|
Let's look at what that could look like in code:
|
|
|
|
.. code:: cpp
|
|
|
|
|
|
// An empty sensor subclass that will "proxy" the temperature values
|
|
class BMP280TemperatureSensor : public sensor::Sensor {
|
|
public:
|
|
BMP280TemperatureSensor(const std::string &name) : sensor::Sensor(name) {}
|
|
std::string unit_of_measurement() override { return "°C"; }
|
|
int8_t accuracy_decimals() override { return 1; }
|
|
};
|
|
|
|
// An empty sensor subclass that will "proxy" the pressure values
|
|
class BMP280PressureSensor : public sensor::Sensor {
|
|
public:
|
|
BMP280PressureSensor(const std::string &name) : sensor::Sensor(name) {}
|
|
std::string unit_of_measurement() override { return "hPa"; }
|
|
int8_t accuracy_decimals() override { return 2; }
|
|
};
|
|
|
|
class BMP180Component : public PollingComponent {
|
|
public:
|
|
Adafruit_BMP085 bmp;
|
|
BMP280TemperatureSensor *temperature_sensor;
|
|
BMP280PressureSensor *pressure_sensor;
|
|
|
|
BMP180Component(const std::string &temperature_name, const std::string &pressure_name, uint32_t update_interval)
|
|
: PollingComponent(update_interval) {
|
|
this->temperature_sensor = new BMP280TemperatureSensor(temperature_name);
|
|
this->pressure_sensor = new BMP280PressureSensor(pressure_name);
|
|
}
|
|
|
|
void setup() override {
|
|
bmp.begin();
|
|
}
|
|
|
|
void update() override {
|
|
// This is the actual sensor reading logic.
|
|
int pressure = bmp.readPressure();
|
|
pressure_sensor->publish_state(pressure / 100.0);
|
|
|
|
float temperature = bmp.readTemperature();
|
|
temperature_sensor->publish_state(temperature);
|
|
}
|
|
};
|
|
|
|
void setup() {
|
|
// ...
|
|
|
|
auto *custom_bmp180 = new BMP180Component("BMP180 Temperature", "BMP180 Pressure", 5000);
|
|
// The BMP180Component is a *component*, so it needs to be registered.
|
|
App.register_component(custom_bmp180);
|
|
|
|
// But the temperature&pressure classes are *sensors*, so each of them needs to be registered
|
|
App.register_sensor(custom_bmp180->temperature_sensor);
|
|
App.register_sensor(custom_bmp180->pressure_sensor);
|
|
|
|
App.setup();
|
|
}
|
|
|
|
That's a lot of code :P Basically, what it boils down to is you have one central component ``BMP180Component``
|
|
which handles the communication with the BMP180 and a ``Sensor`` subclass for each value you want to expose.
|
|
|
|
Most of the magic happens inside the ``update()`` function. Here, the values are read from the BMP180 and are
|
|
sent to esphomelib via the pressure/temperature sensor proxies we set up in the constructor.
|
|
|
|
The only other thing you need to change is the registering inside ``setup()``.
|
|
Because ``BMP180Component`` is a *component* (because it has a lifecycle through the ``setup()`` and ``loop()`` methods),
|
|
it needs to be registered with ``App.register_component(...)``. However, as it's now not a subclass
|
|
of ``Sensor`` anymore, it cannot be registered as a sensor.
|
|
|
|
But because the ``BMP280TemperatureSensor`` and ``BMP280PressureSensor`` *are* subclasses of sensors,
|
|
they do need to be registered so that esphomelib can do all the magic stuff like setting up MQTT discovery
|
|
for them. That's why we call ``App.register_sensor`` for each sensor we created in the end.
|
|
|
|
|
|
See Also
|
|
--------
|
|
|
|
- `Full source code <https://github.com/OttoWinter/esphomelib/blob/master/examples/custom-bmp180-sensor/custom-bmp180-sensor.cpp>`__
|
|
- `Edit this page on GitHub <https://github.com/OttoWinter/esphomedocs/blob/current/esphomeyaml/components/sensor/custom.rst>`__
|
|
|
|
.. disqus::
|