> For the complete documentation index, see [llms.txt](https://docs.petoi.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.petoi.com/mobile-app/app-guide/bittle-x+arm.md).

# Bittle X+Arm

The calibrator interface for Bittle X+Arm is as follows:

<figure><img src="https://1565080149-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MQ6a951Q6Jn1Zzt5Ajr-887967055%2Fuploads%2FC3h2LBws0CMNQoJfKpYI%2Fimage.png?alt=media&amp;token=ea12112d-a8c3-48dc-9949-178cb543ae07" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
The interfaces above will be displayed when you calibrate for the first time. You can also click to open the upper-right menu in the control panel and select **Calibrate** to re-access.\
![](https://1565080149-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MQ6a951Q6Jn1Zzt5Ajr-887967055%2Fuploads%2Fxyt4ZdX48QjMpfWQR265%2Fimage.png?alt=media\&token=4a3f1841-38c7-4ba6-9c52-533dc237f2f9)
{% endhint %}

**For the** pre-assembled kit, you can directly power on the robot and use the mobile app to fine-tune all joints.

**For the construction kit, after** the robot enters the calibration state, do the following steps:

### Install the neck servo and leg servos

{% hint style="info" %}
Note:

You must use the neck section with a J-hook (as pictured below) to avoid the neck from falling when using this robot arm.

<img src="https://1565080149-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MQ6a951Q6Jn1Zzt5Ajr-887967055%2Fuploads%2FNDuzaZkwQ0PrOQLGT0HF%2Fimage.png?alt=media&amp;token=59b45234-e67a-49b9-8816-4c415baf8103" alt="" data-size="original">      ![](https://1565080149-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MQ6a951Q6Jn1Zzt5Ajr-887967055%2Fuploads%2FufonErwiBknxkxFXYawj%2Fimage.png?alt=media\&token=15174d44-399e-4e05-90ca-017e1bf9e314)
{% endhint %}

Installing the neck servo is the same as [installing the head](/mobile-app/app-guide/bittle.md#install-the-head) of Bittle.

Installing the leg servos is the same as [installing the legs](/mobile-app/app-guide/bittle.md#install-the-legs) of Bittle.

### Install the robot arm

This robot arm is already fully assembled. After finishing calibrating the neck servo and the leg servos, power off the robot and [install](/extensible-modules/robot-arm.md#installation) the servo slot on the neck servo with two M2\*5 self-tapping screws.

Then, power on the robot, and do the joint calibration for the servos on the robot arm.


---

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