---json
{
  "name": "Customise & disable"
}
---
====== Customising and disabling built-in devices ======

Change how Axiom handles a device it already knows about. You can customise a copy of a built-in profile, for example to poll a sensor less often, or disable a device type so Axiom stops detecting it.

{{ :axiom:device_library:devlib-devices-changed.png?nolink&800 |}}

===== The Devices tab =====

Connect Axiom and open the **Devices** tab. **Devices on this Axiom** lists every profile Axiom can recognise. Search by name, maker or class (e.g. ''TEMP'' or ''ACC'').

The **State** column shows where each profile comes from:

^ State ^ Meaning ^
| **built-in** | Part of Axiom's firmware. |
| **yours** | Added or customised by your library. |
| **disabled** | Axiom won't try to detect this type. |

Some profiles belong to Axiom's own hardware. For example, the battery fuel gauge (MAX17048) is marked **Required by Axiom** and can't be disabled.

Changes you make here only affect your **draft**. They take effect after you write the library and restart Axiom from the **Install** tab.

===== Viewing a definition =====

Click **Definition** next to a profile to open it read-only in the **Advanced JSON** tab. The page says, for example, //MCP9808 as this Axiom defines it. Read only until you customise it.//

{{ :axiom:device_library:devlib-definition.png?nolink&800 |}}

This is a good way to learn the profile format from working examples.

===== Customising a built-in profile =====

This example makes the MCP9808 temperature sensor poll every 10 seconds instead of every 5.

  - On the **Devices** tab, click **Definition** next to **MCP9808**.
  - Click **Customise this profile**. A copy goes into your draft, labelled **replaces built-in** in the profile list.
  - In the JSON, find ''"pollInfo"'' and change ''"i": 5000'' to ''"i": 10000''. The value is in milliseconds.
  - Click **Save to draft**. The page confirms //Saved to local draft. Axiom has not been changed.//

{{ :axiom:device_library:devlib-customised-draft.png?nolink&600 |}}

**How customised profiles are used:** Axiom tries your copy first. If your copy doesn't identify the device, the built-in profile is still tried as a fallback. A mistake in your copy therefore usually leaves the device working with its built-in behaviour. To be sure your copy is in use, check the **Origin** column on the **Test & tune** tab after installing. It should say **yours**.

<note type="tip">
==Just want to try a different polling rate?==
You can change a device's polling interval temporarily on the **Test & tune** tab without editing or installing anything. See [[axiom:device_library:test_and_tune|Testing and tuning devices]]. Customise the profile once you've found a value you want to keep.
</note>

===== Disabling a device type =====

Click **Disable** next to a profile to stop Axiom detecting that type. Its state changes to **disabled** and the button becomes **Enable built-in**, which undoes it.

Disabling works on the **type**, not on one physical device. Every device of that type stops being detected, and so does any customised copy of it. If you had a customised copy, enabling the type again brings your copy back.

===== Installing your changes =====

Open the **Install** tab. **What will change** lists each change:

{{ :axiom:device_library:devlib-install-changes.png?nolink&800 |}}

  * **override**: your customised copy is tried first.
  * **disable**: Axiom will stop identifying this type.
  * **add**: a new profile (see [[axiom:device_library:add_a_sensor|Adding a new sensor]]).

Tick the review box, click **Write to Axiom**, then click **Restart Axiom**. Check **What Axiom did with the file it has**: your changes are counted under **added** and **disabled**, and **rejected** should be 0.

===== Undoing changes =====

  * **One customisation:** in **Advanced JSON**, select the profile and click **Remove custom**. Then write and restart.
  * **One disabled type:** click **Enable built-in** on the **Devices** tab. Then write and restart.
  * **Everything:** on the **Install** tab, click **Remove library & restart**. Axiom goes back to its built-in profiles. See [[axiom:device_library:backup_and_updates|Backing up, sharing and removing your library]].

<note type="warning">
==Reserved addresses==
Axiom uses some I²C addresses for its own hardware, including ''0x25'', ''0x36'' and ''0x70''–''0x77''. The Device Library's add and customise buttons block profiles on those addresses, and the Catalogue marks such profiles //Reserved for Axiom's own hardware//. Axiom itself refuses a library profile at ''0x36'' (its battery fuel gauge).
</note>