Summary

Since I switched from the Sonic Pad I needed a new Accelerometer. I designed a mount for the following Amazon one. https://www.amazon.com/dp/B0B8MMW2Z9?psc=1&ref=ppx_yo2ov_dt_b_product_details

I created a single and dual magnet version for those of you who want overkill holding. I tested both and there is very little variation which could fall in to standard deviation between tests. But since I made both I might as well provide them.
Tests were done on a MK3s

Make sure you test the polarity with the dual version so they are attracted to each other and don't repulse each other when put together side to side.

https://github.com/FYSETC/FYSETC-PortableInputShaper

Super strong neodymium magnet below can be inserted with a pause at the correct layer.

https://www.apexmagnets.com/magnets/16mm-x-8mm-disc-neodymium-magnet

Print Settings

Printer:

Bambu X1C

                                            Rafts:                      
No

Supports:

                                            Resolution:                      
any

Infill:

any

                Filament:                                     any PLA                                    any                    
                        Notes:                     Nothing special it prints without supports or rafts.

Quick notes about the configuration steps for anyone who needs them:
Test device after plugging it in via Ssh or terminal:
ls -l /dev/serial/by-id/
output:
/dev/serial/by-id/usb-Arduino_RaspberryPi_Pico_B61C61E6295A2597-if00

Software installation
Note that resonance measurements and shaper auto-calibration require additional software dependencies not installed by default. First, run on your Raspberry Pi the following commands:
sudo apt update
sudo apt install python3-numpy python3-matplotlib libatlas-base-dev

Next, in order to install NumPy in the Klipper environment, run the command:
~/klippy-env/bin/pip install -v numpy

cd ~/klipper
make clean
make menuconfig
make flash FLASH_DEVICE=first

go to the klipper/out dir and grab klipper.uf2
With the device removed hold the button down on the device and connect it to the computer. Copy the firmware (klipper.uf2) to the device.
The drive will close and the firmware flash is complete.
Plug it back in and get the new device name.

ls -l /dev/serial/by-id/
/dev/serial/by-id/usb-Klipper_rp2040_E6611CB697255A29-if00

Upload the PIS.cfg to the directory with your printer.cfg and add the [include PIS.cfg] to your printer.cfg only while testing. Comment it out when you’re not testing.

Example PIS.cfg for bedslinger:

[mcu PIS]
;Obtain definition by "ls -l /dev/serial/by-id/" then unplug to verify
serial: /dev/serial/by-id/usb-Klipper_rp2040_E6611CB697255A29-if00

[adxl345]
cs_pin: PIS:gpio13
;spi_bus: spi1a
spi_software_sclk_pin: PIS:gpio10
spi_software_mosi_pin: PIS:gpio11
spi_software_miso_pin: PIS:gpio12
;axes_map: x,-z,y

[resonance_tester]
;accel_chip: adxl345
accel_per_hz: 70
accel_chip_x: adxl345
accel_chip_y: adxl345
probe_points:
150,150,10

To Test for a bed slinger in the klipper web console:
TEST_RESONANCES AXIS=X
TEST_RESONANCES AXIS=Y
;generate results image
~/klipper/scripts/calibrate_shaper.py /tmp/resonancesx.csv -o /tmp/shaper_calibrate_x.png
~/klipper/scripts/calibrate_shaper.py /tmp/resonancesy.csv -o /tmp/shaper_calibrate_y.png

Add results to your printer.cfg
[input_shaper]
shaper_type_x = mzv
shaper_freq_x = 47.6
shaper_type_y = mzv
shaper_freq_y = 25.4