Custom UART Device


Custom components are deprecated, not recommended for new configurations and will be removed from ESPHome in a future release. Please look at creating a real ESPHome component and “importing” it into your configuration with External Components.

You can find some basic documentation on creating your own components at Contributing to ESPHome.


While we try to keep the ESPHome YAML configuration options as stable as possible, the ESPHome API is less stable. If something in the APIs needs to be changed in order for something else to work, we will do so.

Lots of devices communicate using the UART protocol. If you want to integrate a device into ESPHome that uses this protocol you can pretty much use almost all Arduino-based code because ESPHome has a nice abstraction over the UART bus.

See the other custom component guides for how to register components and make them publish values.

#include "esphome.h"

class MyCustomComponent : public Component, public UARTDevice {
  MyCustomComponent(UARTComponent *parent) : UARTDevice(parent) {}

  void setup() override {
    // nothing to do here
  void loop() override {
    // Use Arduino API to read data, for example
    String line = readString();
    int i = parseInt();
    while (available()) {
      char c = read();
    // etc

And in YAML:

# Example configuration entry
    - my_custom_component.h

  id: uart_bus
  tx_pin: GPIOXX
  rx_pin: GPIOXX
  baud_rate: 9600

- lambda: |-
    auto my_custom = new MyCustomComponent(id(uart_bus));
    return {my_custom};

See Also