Remixed from the original to reduce the size a little, and add mounting holes for Ender3S1 extruder.

You will need two M3*4mm heat-inserts and two M3*5mm screws.

Extruder mount is done on the top most 2 screws that hold the extruder to the carriage.

Bed mount is done via binder clip.

 

Below are my cfg includes, refer to the original for wiring and flashing the RP2040 with klipper. Remeber to change the serial ports to your printer's specific port by-id!

adxl345_pico_bed.cfg

[mcu pico]
serial: /dev/serial/by-id/usb-Klipper_rp2040_E6614C30939A782A-if00
[adxl345]
cs_pin: pico:gpio1
spi_bus: spi0a
Attached to bed
axes_map: x, y, z
[resonance_tester]
accel_chip: adxl345
probe_points:
    # Somewhere slightly above the middle of your print bed
    110, 124, 20
[output_pin power_mode] # Improve power stability
pin: pico:gpio23

adxl345_pico_hotend.cfg:

[mcu pico]
serial: /dev/serial/by-id/usb-Klipper_rp2040_E6614C30939A782A-if00
[adxl345]
cs_pin: pico:gpio1
spi_bus: spi0a

Attached to hotend
axes_map: z, x, y
[resonance_tester]
accel_chip: adxl345
probe_points:
Somewhere slightly above the middle of your print bed
   110, 124, 20
[output_pin power_mode] # Improve power stability
pin: pico:gpio23

I just include them one at a time from my printer.cfg and run TEST_RESONANCES AXIS=Y and TEST_RESONANCES AXIS=X respectively, see Klipper docs for more info.

# [include adxl345_pico_bed.cfg] # Comment this out when you disconnect the accelerometer

[include adxl345_pico_hotend.cfg] # Comment this out when you disconnect the accelerometer