printer.conf and other notes for installing Klipper on a stock BIQU B1 with a Pi Zero 2 W using UART
Follow MainsailOS Installation Guide to image the SD card.
Before moving SD card to the PI, edit the following files using a proper text editor (VSCode, Vim, Notepad++, nano, etc)
mainsailos-wpa-supplicant.txt - update your network ID and password:
network={
ssid="MyNetworkSSID"
psk="Pa55w0rd1234"
}
config.txt - replace the last section with:
[pi0w]
enable_uart=1
dtoverlay=pi3-miniuart-bt
With the Pi still disconnected from the printer, insert the SD and power it up using a USB adapter for now (eventually it will be powered using the 5V from the UART connection).
After a minute or two, you should be able to point your browser on any computer on the same network to http://mainsailos.local and see the Mainsail dashboard. There's probably a handful of warnings, but we're not done yet so that's to be expected.
In the Machine tab, use the Update Manager panel to update klipper, moonraker, and mainsail if available. The System OS-Packages update likely won't work yet, we'll address that below.
For the next few steps, you'll need to SSH into the Pi (using PuTTY on Windows, terminal on Mac or Linux), the IP should be mainsailos.local, default username and password are pi and raspberry.
It's a good idea to update all the packages on the Pi manually at first, though in the next step we'll enable Moonraker to do this via the dashboard (this may take a while):
sudo apt update
sudo apt upgrade
To give Moonraker the permissions is needs in order to perform some tasks like updating OS packages, run the following:
cd ~/moonraker/scripts
./set-policykit-rules.sh
sudo service moonraker restart
Last step before moving on to the printer is creating the config file that Klipper will use to define your machine. You can type this via SSH by creating a file in ~/klipper_config called printer.cfg, though it's likely easier through the Mainsail dashboard on your computer.
In the Config Files panel of the Machine tab, ensure the Root dropdown is set to "config", click Create File and name it printer.cfg.
Copy/Paste my config file into the editor, then click Save and Restart
Before we can connect the Pi, we have to flash the Klipper firmware to the printer's mainboard which in our case is an SKR V1.4
SSH into the Pi and run the following commands to bring up the firmware configuration menu:
cd ~/klipper/
make menuconfig
This should bring up a settings menu you can navigate with the arrow keys and space bar. Here are the settings we need for our hardware:
Note the specific UART port (UART0 P0.3/P0.2) and that we are using a "Smoothiware bootloader"
Hit Q to save and quit, the run
make
to generate the firmware file, which will be located at ~/klipper/out/klipper.bin
We need to get that file off of the Pi and on to a separate SD card to flash the mainboard. Use something like WinSCP or Filezilla on PC or scp in the terminal on Mac or Linux to move klipper.bin to your computer and on to the other SD card. You also need to rename it to firmware.bin in order for the printer to recognize it.
Stick the SD card into the printer (in the TF Card slot closer to the gantry, not the one by the click-wheel which is part of the touch screen), power on the printer, and wait a few minutes.
To verify that the firmware was flashed, remove the SD card, plug it into your computer and check that firmware.bin was renamed to firmware.cur
With the printer and Pi powered off and unplugged, remove the bottom panel to access the mainboard. We have 3 tasks in here:
- Remove the ribbon cable connecting the mainboard to the touch screen. It won't work with Klipper (yet) and we need one of the ports for the UART connection to the Pi
- Move the filament runout sensor connector (labelled FLD) from the touchscreen to the E0DET port on the mainboard (see SKR V1.4 ReferenceDiagram, about halfway up the right side).
- Construct and connect the cable assembly you will use for the Pi to the UART connection labelled TFT (where the touchscreen used to be connected). See Nero 3D's excellent video for an example cable assembly. The pin connections should be as follows:
| Pi GPIO Pin | Purpose | SKR V1.4 TFT Pin |
|---|---|---|
| 4 | 5V | NPWR |
| 6 | GROUND | GND |
| 8 | TX->RX | RX0 |
| 10 | RX<-TX | TX0 |
Because we are using the 5V from this connection, you will no longer need to power the Pi with the USB adapter.
After you've triple checked your wiring, it's time to power on the printer again. This should also power on the Pi and after a few moments you should be able to reconnect your browser to mainsailos.local to verify that everything is up and running and configured correctly.
Before you start printing, it's definitely recommended to go through and test that everything is set up correctly. Follow the steps in the Klipper docs or in Nero 3D's walkthrough.
Note that pressure_advance and input_shaper settings have been commented out in my printer.cfg, you should calibrate those settings for your own printer. Again, the official Klipper docs and Nero 3D are both great resources for these processes.
Let me know in an Issue if you run into any problems following these steps, we're all in this together. Keep your stick on the ice, I'm pulling for you.