esphome-docs/custom/custom_component.rst
Otto Winter f4c1d31a1d
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Generic Custom Component
========================
This integration can be used to create generic custom components in ESPHome
using the C++ (Arduino) API. This integration should be used in cases where
none of ESPHome's abstraction layers (for example the "sensor", "binary sensor",
"switch", etc concepts) work well for your integration.
Please first read :doc:`/components/sensor/custom` guide, the same principles apply here.
The example below is an example of a custom component that can do anything you want really.
.. code-block:: cpp
#include "esphome.h"
using namespace esphome;
class MyCustomComponent : public Component {
public:
void setup() override {
// This will be called once to set up the component
// think of it as the setup() call in Arduino
pinMode(5, INPUT);
pinMode(6, OUTPUT);
}
void loop() override {
// This will be called very often after setup time.
// think of it as the loop() call in Arduino
if (digitalRead(5)) {
digitalWrite(6, HIGH);
// You can also log messages
ESP_LOGD("custom", "The GPIO pin 5 is HIGH!");
}
}
};
In many cases however components should communicate with other appliances using the network.
That's why there is :cpp:class:`mqtt::CustomMQTTDevice`. It is a helper class to create
custom components that communicate using MQTT.
.. code-block:: cpp
#include "esphome.h"
using namespace esphome;
class MyCustomComponent : public Component, public mqtt::CustomMQTTDevice {
public:
void setup() override {
// This will be called once to set up the component
// think of it as the setup() call in Arduino
pinMode(6, OUTPUT);
subscribe("the/topic", &MyCustomComponent::on_message);
// also supports JSON messages
subscribe_json("the/json/topic", &MyCustomComponent::on_json_message);
}
void on_message(const std::string &payload) {
if (payload == "ON") {
digitalWrite(6, HIGH);
publish("the/other/topic", "Hello World!");
} else {
digitalWrite(6, LOW);
publish("the/other/topic", 42);
}
}
void on_json_message(JsonObject &root) {
if (!root.containsKey("key"))
return;
int value = root["key"];
// do something with Json Object
// publish JSON using lambda syntax
publish_json("the/other/json/topic", [=](JsonObject &root2) {
root2["key"] = "Hello World";
});
}
};
(Store this file in your configuration directory, for example ``my_custom_component.h``)
And in YAML:
.. code-block:: yaml
# Example configuration entry
esphome:
includes:
- my_custom_component.h
custom_component:
- lambda: |-
auto my_custom = new MyCustomComponent();
return {my_custom};
Configuration variables:
- **lambda** (**Required**, :ref:`lambda <config-lambda>`): The lambda to run for instantiating the
binary sensor(s).
See :cpp:class:`Component` and :cpp:class:`mqtt::CustomMQTTDevice`.
See Also
--------
- :ghedit:`Edit`
.. disqus::