Connecting a Hermit Crab CAN Bus to the BIGTREETECH BTT Octopus Pro V1.0

This article details the steps needed to connect a Hermit Crab CAN Bus to a BIGTREETECH BTT Octopus Pro V1.0 microcontroller unit.

The documentation for the Hermit Crab CAN Bus version has wiring diagram examples for directly connecting the Hermit Crab BTT HotMode to a raspberry pi via USB and to via a BTT CAN-Distribution board. It does not, however, have a wiring diagram or instructions for how to use the Octopus Pro as a USB to CAN Bus adapter.

To create this guide I utilized the following sources:

• https://github.com/Esoterical/voron_canbus/tree/main
• https://www.reddit.com/r/klippers/comments/nil6e8/klipper_ls_cannot_access_devserialbyid_no_such/
• https://github.com/bigtreetech/HermitCrab/blob/master/HERMIT%20CRAB%20USER%20MANUAL.pdf

Total Bill of Materials for this Project

Old Enclosure from Another Project

24 Volt Meanwell PSU

Raspberry Pi 4 Model B

BigTechTree Octopus Pro v1.0

BigTechTree Hermit Crab

Hemera Extruder

Creality CR10 v2 

After the sources listed were published, CanBoot was renamed Katapult, so I will refer to CanBoot as Katapult throughout this article, as that is it's name as I am writing this guide.

I'm an Octoprint man myself, never having tried Moonraker before. But as indicated on reddit, for some reason the Octoprint w/ Klipper image from the Raspberry Pi Imager doesn't work, so I ended up for the first time using Moonraker, and then the Esoterical guide worked fine. So, steps were as follows:

1. In Raspberry Pi Imager v1.8.1, click the Choose OS button->Other Specific Purpose OS->3D Printing->Mainsail OS->Mainsail OS 1.2.1 32-Bit. Install that do a mini-SD card, and load that into the Pi.
2. Connect the Octopus Pro board to the Raspberry Pi with a USB cable.
3. Build the Katapult bootloader using the following settings:
4. Flash the Katapult bootloader to the Octopus Pro
5. Build Klipper for the Octopus Pro using the following settings:
6. Flash Klipper to the Octopus Pro.
7. Connect the Hermit Crab tool head to the Raspberry Pi via it's microusb port. I tried using the USB C port which did not work. I do not think it provides USB connection.
8. Build Klipper for the Hermit Crab Toolhead using the following settings:
9. Boot up the Pi.
10. Setup the can network by uploading the following file to the following directory:
11. Provide Mainsail with the configuration file it needs by uploading this printer.cfg file to this directory.
12. Reboot the Pi.
13. Wire everything up according to this wiring diagram.