# Hardware Peripherals

{% hint style="warning" %}
These APIs are likely to change in future API versions. Key functionality will remain.
{% endhint %}

Accessing hardware connected to Skynode can be achieved by mapping the correct device file into the app container.

{% hint style="danger" %}
The UART port on Skynode is connected to the FMU and can thus not be used to connect serial peripherals to apps. To connect UART payloads to Skynode, use a UART-to-USB adapter chip, like the FTDI series of chips.
{% endhint %}

### Libusb devices

Devices that can be mounted with libusb user-space drivers can be mapped like this

* Map `/dev` from the host to your containter
* Add `c 189:* rmw` cgroup rule

This can be done like this, by using the [compose-override](/app-development/app-framework/compose-override.md) functionality in auterion-app.yml:

```yaml
compose-override:
    services:
        my-service:     # Replace with the name of your service
            volumes:
                - /dev:/dev
            device_cgroup_rules:
                - 'c 189:* rmw'
```

### Serial-to-USB devices

Similarly to libusb devices, serial to usb devices can be mapped like so

<pre class="language-yaml"><code class="lang-yaml"><strong>compose-override:
</strong><strong>    services:
</strong>        my-service:    # Replace with the name of your service
            volumes:
                - /dev:/dev
            device_cgroup_rules:
                - 'c 166:* rmw'  # For CDC / ACM devices
                - 'c 188:* rmw'  # For tty devices (FTDI)
</code></pre>

### Video for Linux (v4l) devices

Similarly to the other devices types, these devices can be mapped like so

```yaml
compose-override:
    services:
        my-service:    # Replace with the name of your service
            volumes:
                - /dev:/dev
            device_cgroup_rules:
                - 'c 81:* rmw' 
```

{% hint style="danger" %}
There is currently no managed access de-confliction for devices. When a device gets opened by one app, other apps can not open this device anymore.
{% endhint %}


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