Before building or designing your own add-ons, please review the notes below. They will help you choose the right parts and avoid common mistakes.

1. Mounting Screws
All add-ons use M2.5 mounting screws. Do not use screws longer than 8 mm. M2.5 × 8 mm Phillips round head machine screws are compatible with every listed add-on.

2. Custom Designs
You can use the drawing template below when creating your own custom add-ons. It follows Doly’s contact surface design to help your add-on fit properly. You may also need a center rectangular opening for IO port access. STL and STEP files are available in the GitHub repository.

3. Powered Add-Ons
For powered add-ons, always check connector polarity before installation. Incorrect connections may damage your robot, so please double-check before powering anything on.

4. Servo Connector Pinout
Use the servo connector pinout diagram below as a reference when connecting servo-based add-ons.

5. Additional Screws
Some add-ons may need extra screws. We recommend 2 mm × 5 mm round head self-tapping plastic screws, but you can choose different types depending on your custom design.

6. Magnets
Some add-ons may also require magnets. We recommend 2 × 5 mm neodymium magnets. Other magnet sizes may also work, but you may need to adjust the 3D model for a proper fit.