---
layout: component
title: "Arduino"
description: "Instructions how to setup an Arduino boards within Home Assistant."
date: 2015-06-27 10:28
sidebar: true
comments: false
sharing: true
footer: true
logo: arduino.png
ha_category: DIY
featured: true
---

The [Arduino](https://www.arduino.cc/) device family are microcontroller boards that are often based on the ATmega328 chip. They come with digital input/output pins (some can be used as PWM outputs), analog inputs, and a USB connection. The equipment depends on the [type](https://www.arduino.cc/en/Main/Products) of board. The most common ones are the Arduino Uno and the Arduino Leonardo with 14 digital input/output pins and 6 analog input pins.

There are a lot of extensions (so called [shields](https://www.arduino.cc/en/Main/ArduinoShields)) available. Those shields can be plugged-in into the existing connectors and stacked on top of each other. This makes it possible to expand the capabilities of the Arduino boards. 

The arduino component is designed to let you use a directly attached board to your Home Assistant host over USB.

You need to have the [Firmata firmware](https://github.com/firmata/) on your board. Please upload the `StandardFirmata` sketch to your board, please refer to the [Arduino documentation](https://www.arduino.cc/en/Main/Howto) for further information.

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

```yaml
# Example configuration.yaml entry
arduino:
  port: /dev/ttyACM0
```

Configuration variables:

- **port** (*Required*): The port where your board is connected to your Home Assistant host. If you are using an original Arduino the port will be named `ttyACM*` otherwise `ttyUSB*`.

The exact number can be determined with the command shown below.

```bash
$ ls /dev/ttyACM*
```

If that's not working, check your `dmesg` or `journalctl -f` output. Keep in mind that Arduino clones are often using a different name for the port (eg. `/dev/ttyUSB*`).

<p class='note warning'>
A word of caution: The Arduino boards are not storing states. This means that with every initialization the pins are set to off/low.
</p>

