Pico Claw Machine

DIY claw machine built using an affordable replacement claw powered by a Raspberry Pi Pico.

The claw machine works with free movement on all axes, making it an ideal toy for many different uses (Lego, Playmobil, etc.)

Requirements:

• Raspberry Pico W with micro python (https://micropython.org/download/RPI_PICO_W/)
• Replacement Claw (https://fr.aliexpress.com/item/1005006730772049.html)
• Guide Rails (https://fr.aliexpress.com/item/1005007520507786.html)
• DC Motor Controller x2 (https://fr.aliexpress.com/item/1005006308936405.html)
• Some buttons and an arcade stick (https://fr.aliexpress.com/item/4000029640022.html)
• 12V power supply (reused a 12V 2.5A one from an old router)
• Male Dupont headers and some wires to create a custom cable that interfaces with the replacement claw’s connector (https://fr.aliexpress.com/item/1005006034877497.html)

Note: You'll need to build a structure capable of supporting the claw. I built mine using recycled materials, so I don't have any specific material references for its construction

Micro Python

Download the .uf2 file from Raspberry Pi Pico W downloads (https://micropython.org/download/RPI_PICO_W/). Hold the BOOT button while plugging in your Pico, then drop the .uf2 file onto the mounted Pico drive.

Use Thonny IDE or another method to write the main.py file.

Installation

• Create a custom cable using 2x8 male dupont header to interface with the claw connector.
• Connect the X and Y motors to DC Motor Controller 1 and provide a 12V power supply.
• Connect the Z motor and the claw to DC Motor Controller 2 and provide a 12V power supply.
• Connect both DC Motor Controllers to the Raspberry Pi Pico according to the pinout below
• Use the 3.3V out from one of the motor controller to power the Pico Vsys pin.
• Connect the necessary buttons and limits for operating the claw machine as shown in the pinout below.

Note: We use X, Y, and Z axes as if viewing the claw machine from above. X refers to the motor that controls the internal movement of the claw assembly, Y is the movement along the guide rails, and Z is the axis used to raise and lower the claw.

Note: First motor controller X with D0, D1 and Y with D2, D3. Second motor controller Z with D0, D1 and button claw (pince) with D2.

Replacement Claw Pinout

Pico W Pinout

Additional Notes

• There is no official documentation available for the replacement claw. Based on testing, I assume the motors run on 12V and perform well at this voltage. The electromagnet also works adequately at 12V, but delivers stronger holding force when powered with 24V.
• The connector used for the replacement claw appears to be proprietary, I couldn’t find any reference or standard model for it. This is why creating a custom cable is useful.
• The limit switch for controlling the claw’s descent works as follows: when the claw is relieved of its own weight (when it touches the ground), the switch is triggered. Making easy to work with any height.
• For some reasons, the replacement claw includes motor limit switches on all axes and directions except for X (right). It might be a good idea to add one.
• The motor controllers support a voltage range of 5V to 14V, which allows you to adjust the movement speed or the claw’s gripping force as needed.