Nozzle ADXL345 Accelerometer

Finally a PCB that mounts exactly where you need to measure ressonance!
Designed by Boxxy from Provok3d the new Nozzle Accelerometer is a solution that makes the best ressonance readings of the market because it’s hard mounted to the nozzle itself.  It fits all printers with a v6 nozzle and it’s designeded to make Klipper’s input shaping much easier by simplifying the wiring and config for measuring resonances. You just need this PCB and a USB-C cable that we also provide as optional. Just Plug and Play! This product is pre-flashed with Ampon but can also be flashed with Klipper.

The hole in the PCB is designed to fasten the device directly onto the heater block with the nozzle “hard mounting”, which eliminates the need for additional hardware and reduces installation complexity. The device can be easily installed and removed from the heater block with the nozzle without the need for additional tools.

• Better accuracy: Hard mounting an accelerometer directly onto the surface of the test object provides a more accurate measurement of the vibration. This is because the accelerometer is in direct contact with the object, and there is no potential for the accelerometer to shift or move during testing, which could introduce errors in the measurement. In contrast, plastic mounting can introduce some flexibility or movement between the accelerometer and the test object, which can lead to inaccuracies in the measurement.
• Increased sensitivity: Hard mounting an accelerometer can increase its sensitivity to low-level vibrations. By mounting the accelerometer directly onto the surface of the test object, it can pick up even subtle vibrations that might not be detected using a plastic mounting. This can be particularly important for applications where precise measurement of low-level vibrations is critical.

 

 

 

Very important: while this board is attached do not heat the hotend!

Options available:

• Nozzle ADXL345 already pre-flashed with Ampon
• Nozzle ADXL345 already pre-flashed with Ampon + 1,5 meters long USB-C cable rated upto 5Amp

Author, credits and partnership: https://provok3d.com/product/nozzle-adxl-board/ 

Pictures from Boxxy, Simon Vez from Vzbot, Rogerlz, Diem

How to install this Nozzle ADXL345

1. heat your hotend nozzle temperature up to 250ºc. unload filament. remove the nozzle.
2. let the printer cool down completely and turn off the printer.
3. place the nozzle through the PCB and attach it to the extruder. leave the silicione sock. connect the usb cable from the PCB to the raspberry. turn on the printer.
4. make all the readings and tunnings necessary but never heat up the hotend!
5. once done remove the PCB and the nozzle. reattach the nozzle only to the hotend. heat up the hotend at 120ºc and tight the nozzle a little but further. start printing!

How to Configure Klipper

[mcu ampon]
serial: /dev/serial/by-id/usb-Anchor_Ampon-if00

[adxl345]
cs_pin: ampon:CS

[resonance_tester]
accel_chip: adxl345
probe_points: 90, 90, 20

How to auto tune the input shaper?

First, read this https://www.klipper3d.org/Resonance_Compensation.html don’t forget to tune pressure advance and all the other parameters. Input shaper should be the very last fine tunning proccess.

install the necessary dependencies via ssh:

~/klippy-env/bin/pip install -v numpy
sudo apt update 
sudo apt install python3-numpy python3-matplotlib

back to the mainsail, edit printer.cfg and make sure you included the previous topic klipper configuration

test the connection between adxl345 and rapsberry. in mainsail terminal console run/send this code:

ACCELEROMETER_QUERY

you should receive something similar to this format:

Recv: // adxl345 values (x, y, z): 470.719200, 941.438400, 9728.196800

if not. please re-check your wiring or klipper config. something is wrong.

edit once again printer.cfg but now, this time, edit the printer section

[printer]
kinematics: corexy
max_accel: 10000
max_accel_to_decel: 10000
square_corner_velocity: 5.0

[input_shaper]

now…. let’s run the auto tune.

in mainsail terminal run this code:

SET_VELOCITY_LIMIT ACCEL_TO_DECEL=10000
SET_PRESSURE_ADVANCE ADVANCE=0
SET_INPUT_SHAPER SHAPER_FREQ_X=0 SHAPER_FREQ_Y=0

If you HOME the printer the nozzle adxl will colide with the bed. Becareful! Fake the homing of the z axis by touching the TAP or the z sexbolt.

SHAPER_CALIBRATE

when it’s done run this code

SAVE_CONFIG

Edit printer section and revert max accel and decel to 4000.

restart and it should be it 🙂