home-assistant.io/source/_integrations/firmata.markdown

title, description, ha_category, ha_release, ha_iot_class, ha_codeowners, ha_domain

title	description	ha_category	ha_release	ha_iot_class	ha_codeowners	ha_domain
Firmata	Connect Arduino-compatible boards within Home Assistant	DIY Binary Sensor Switch	0.114	Local Push	@DaAwesomeP	firmata

Firmata can be used to add digital inputs and outputs to Home Assistant. Currently, this component supports high/low digital inputs and outputs. This allows for buttons, switches, motion detectors, relay control, etc. The component can currently connect to a Firmata board via serial or serial over USB.

The Firmata protocol is a standard protocol for microcontrollers. Most of these boards are support digital and analog inputs and outputs. Arduino and Arduino-compatible microcontroller development boards are the most popular boards to use with Firmata.

There is currently support for the following device types within Home Assistant:

• Binary Sensor
• Switch

Configuration

You will need to upload a Firmata firmware to your board. Please upload any StandardFirmata sketch to your board; please refer to the Arduino documentation for further information for uploading sketches. Firmata is available in the Arduino Library Manager in the Arduino IDE. You may also use a Firmata Express.

To integrate Arduino boards with Home Assistant, add the following section to your configuration.yaml file:

Firmata does not store the last state across power cycles. This means that with every powerup the pins are set to off/low and after every initialization, they will be set to the default that you have configured in YAML.

Firmata may cycle pins HIGH/LOW during initialization. If your pins should not be accidentally cycled, you may need to modify your Firmtata sketch or if you are using a relay board use an output pin as VCC. See this issue for details: Make initial pin value configurable.

You may configure multiple Firmata boards. Each board has the following options:

{% configuration %} serial_port: description: The port where your board is connected to your Home Assistant host. It is recommended to use the by-id reference (instead of numerical like /dev/ttyACM0 or /dev/ttyUSB0) since these will never change after a reboot. If you are using HassOS, you can find a list of connected serial devices in the Hardware dialog on the System tab of the Supervisor. required: true type: string serial_baud_rate: description: The baud rate of the Arduino sketch. If you are using Firmata Express, then you do not need to set this option. If you are using the default StandardFirmata, then you should set this to 57600. required: false type: integer arduino_instance_id: description: If you are using Firmata Express, then this should match the instance number that you set in the sketch. required: false type: integer arduino_wait: description: Time in seconds to wait for the Arduino is initially respond. May need to be used for boards that respond slowly at first connection. required: false type: integer sleep_tune: description: Time in seconds to wait for reply from the Arduino after sending a command. Rarely needs to be adjusted. required: false type: float sampling_interval: description: Sampling interval in millseconds sent to Firmata. Most Firmata sketches will ignore any interval less than 10 milliseconds. required: false type: integer switches: description: Digital high/low outputs to configure required: false type: list keys: name: description: The name of the entity to create in Home Assistant required: true type: string pin: description: The digital pin number on the board. required: true type: integer pin_mode: description: The digital pin output mode. For switches, this must be set to OUTPUT. No other output modes are currently implemented. required: true type: integer initial: description: The initial output of the pin after initialization. Note that this is inverted if negate is enabled. required: false default: False type: boolean negate: description: Flips the output of the digital pin required: false default: False type: boolean binary_sensor: description: Digital high/low input to configure required: false type: list keys: name: description: The name of the entity to create in Home Assistant required: true type: string pin: description: The digital pin number on the board. required: true type: integer pin_mode: description: The digital pin input mode. Supported modes are INPUT and PULLUP. Check your board specifications to see which pins have optional internal pullups available. required: true type: integer negate: description: Flips the input of the digital pin required: false default: False type: boolean {% endconfiguration %}

If you double-configure a pin, the integration will fail to configure the second one that it attempts to set up and will log an error.

# Example firmata configuration.yaml entry
firmata:
  - serial_port: /dev/serial/by-id/usb-Teensyduino_USB_Serial_358320-if00
    serial_baud_rate: 57600
    switches:
      - name: my_light
        pin_mode: OUTPUT
        pin: 4
        negate: true
      - name: my_other_output
        pin_mode: OUTPUT
        pin: 5
        initial: true
      - name: my_light
        pin_mode: OUTPUT
        pin: 6
        initial: true
        negate: true
    binary_sensors:
      - name: my_motion
        pin_mode: INPUT
        pin: 2
      - name: my_door
        pin_mode: PULLUP
        pin: 3
        negate: true