View source for Klipper + ADXL345 Input Shaper guide

=== Guide ===
# Aquire an ADXL345
# Solder 6 wires on to the ADXL345.
# Monut the ADXL to you Extruder. If you got a moving printbed as X you need to move the ADXL345 halfway into the calibration guide. Watch NEROs video!
# Connect the 6 wires to your Raspberry Pi - DO it correct please or you COULD risk frying either your ADXL345, Your Raspberry Pi... or both ;-)
# Install the software - if you havent done so already.
# Update your Raspberry Pi: 
# <blockquote><code>sudo apt update -y</code></blockquote>
# <blockquote><code>sudo apt upgrade -y</code></blockquote>
# Install "numpy" - ''Note: this will take quite some time - NERO says 20 minutes. It was faster on my Raspberry Pi 4 but still...''
# <blockquote><code>~/klippy-env/bin/pip install -v numpy</code></blockquote>
# Install additional dependencies
# <blockquote><code>sudo apt install python-numpy python-matplotlib</code></blockquote>
# Configure your Raspberry Pi as a secondary MCU - ''Note: I got this working together with screen on my Creality Ender 5 Plus :-)''
# <blockquote><code>sudo cp ~/klipper/scripts/klipper-mcu-start.sh /etc/init.d/klipper_mcu</code></blockquote>
# <blockquote><code>sudo update-rc.d klipper_mcu defaults</code></blockquote>
# Rebuild the microcontroller code:
# <blockquote><code>cd ~/klipper/</code></blockquote>
# <blockquote><code>make menuconfig</code></blockquote>
# Select "Micro-controller Architecture (Linux process)"
# Select "(X) Linux process" - make sure the X is set.
# Press Q 
# Respond Yes to save changes.
# Stop the klipper service:
# <blockquote><code>sudo service klipper stop</code></blockquote>
# Build and flash the new code to the microcontroller.
# <blockquote><code>make flash</code></blockquote>
# Start the klipper service again.
# <blockquote><code>sudo service klipper start</code></blockquote>
# Make sure the Linux SPI driver is enabled:
# <blockquote><code>sudo raspi-config</code></blockquote>
# Select "3 Interface Options"
# Select "P4 SPI"
# Respond Yes to the question "Would you like the SPI interface to be enabled?"
# Respond Ok to the information that "The SPI interface is enabled"
# Press TAB twice to mark the "Finish" button.
# Press Enter.
# Open your klipper configuration file in your favorite linux text-editor. I use nano.
# <blockquote><code>nano ~/printer.cfg</code></blockquote>
# copy the ''Additional lines'' below.
# paste the ''Additional lines'' into your klipper configuration file above the [mcu] section.
# Save the changes in the klipper configuration file.
# Exit the texteditor.
# Issue the "restart" command in your klipper terminal window - I use OctoPrint for this.
# Software is now fully installed and configured.
# Test if the ADXL345 is recognised and talking with Klipper.
# Issue the "ACCELEROMETER_QUERY" command in your klipper terminal window - I use OctoPrint for this.
# You should get a resonse that looks like this:
# <blockquote><code>Recv: // adxl345 values (x, y, z): 611.934960, 305.967480, 11473.780500</code></blockquote>
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==== Additional lines ====
<pre>
[mcu rpi]
serial: /tmp/klipper_host_mcu

[adxl345]
cs_pin: rpi:None

[resonance_tester]
accel_chip: adxl345
probe_points:
    150,150,20  # an example
</pre>

=== Credits ===
I wrote this guide using NERO 3Ds Youtube video as inspiration, so I hade the commands needed handy to cut'n paste into my Raspberry Pi when ever I want to rerun the calibration.