Using Raspberry Pi Pico with u2d2 board

[Yahya_amirinejad]

Hello,
Considering that we intend to use Dynamixel servos for our robotics project, if we use the U2D2 board for coding the robot (using Python), can we utilize a Raspberry Pi Pico for wireless communication between the U2D2 board and the computer? Please guide us in this matter.
Thank you

[kneave]

The U2D2 requires a USB host to plug in to, the Pico doesn’t have this capability. You could however just connect to the servos directly, I’ll bet that you can program the PIO to act as a suitable half-duplex serial port.

[roboteer]

@Yahya_amirinejad

As I do not have a RPi Pico board on hands, so I can only “propose” (and not verify) the following approach:

1. Use the UART Ports on the RPi Pico with the DXL MKR shield:

ROBOTIS e-Manual

2. Use the Dynamixel2Arduino library installed to RPi Pico to control the DXLs

GitHub - ROBOTIS-GIT/Dynamixel2Arduino: DYNAMIXEL protocol library for Arduino

Now, I do not know if the D2A library is compatible with the RPi Pico’s Core M0+ controller or not, so this is a crucial test.

Please see this post as an example of interfacing ESP32 with DXL MKR board:

ESP32 + DXL Shield MKR Mashup in ARDUINO

Although the ESP32 and the DXL MKR Shield are not “purposedly” made for each other, they are well supported within the ARDUINO environment. Just looking at their respective schematics, it looked like that there was a possibility that they could be hooked up together. My experiment setup is shown below: [ESP32_DXL_1] Two 2XL-430s are used and they are powered at 12V via the DXL MKR Shield. My ESP32 board is a Feather ESP32 V2 from Adafruit. It is powered via the USB-C Port by my PC. …

[Yahya_amirinejad]

Thank you for your reply, but we want to use U2D2 for our motion control, and we want to use raspberry pie pico for connecting U2D2 to computer wireless. Could you help me?

[Jonathon]

@Yahya_amirinejad

As Kneave stated, the RaspberryPi Pico is not compatible with the U2D2 controller.

You may be able to implement one of the solutions suggested by roboteer and control your DYNAMIXELs directly from the UART of the Pico. If you do go this route, then this community page post may be helpful in establishing UART communications.

RPi driving dynamixel from UART at 1Mbps

I have tested a proof of concept of driving a XL430 from the UART port of a RPi at 1Mbps. The RPi has 2 UARTs: UART1 and mini UART. The mini UART isn’t stable at 1Mbps but the hardware of the UART1 is capable of much faster speeds than 1Mbps, the main limitation is the operating systems usage of the UART. To get a stable 1Mbps from RPi UART I had to enable UART1 and increase the UART clock speed as the default clock speed is too low to generate UART at 1Mbps. I added the following 2 lines to t…

[Yahya_amirinejad]

Thank you @Jonathon
But the problem is that I wanna do a robotic projet, and I wanna coding by U2D2 ( not raspberry pie) . And I wanna connect U2D2 to PC wireless, ( because I have limitation in wiring in this project ). Do you have any idea to solve my problem?

[Jonathon]

The U2D2 does not have support for any wireless access modes.

Using the RaspberryPi Pico UART directly is almost certainly the simplest way to achieve the sort of control you are asking for.

[kneave]

Aye, if you go with a Pico W you could even configure it to act as a Bluetooth serial port but you would need to code this yourself.