Accelerometer (CORE One, MK4/S, MK3.9/S)

The Input Shaper functionality on the Prusa CORE One, and on the Original Prusa MK4/S, MK3.9/S can be calibrated using an optional accelerometer.

The accelerometer assembly consists of a small PCB enclosed in a printed cover, which connects to the printer. Please note that using the accelerometer requires partial disassembly of the printer.

The input shaper is pre-calibrated from the factory, so this calibration is usually unnecessary on a stock printer. However, if you've made any modifications to the printer hardware, it may be beneficial to recalibrate the settings using the accelerometer.

Prusa CORE One

Temporarily remove the Wi-Fi board cover, by loosening its M3x12 screw.

Connect the jumper cable between the xBuddy connector and the Wi-Fi module connector.

Remove the circular cover on the back. Then, route the accelerometer cable in the hole.

Connect the accelerometer cable to the connector at the back of the printer.

Original Prusa MK4/S, MK3.9/S

On MK4S and MK3.9S, connect the accelerometer to the dedicated port on the xBuddy board.
Alternatively, you can install a short jumper cable between the xBuddy and the Wi-Fi module on the back of the printer. Then, you can connect the accelerometer to the connector on the back of the printer.

On MK4 and MK3.9, connect the cable to the accelerometer's PCB and attach the printed covers. The accelerometer connects directly to the dedicated port on the xBuddy board.

Without the jumper cable, the connector on the rear of the printer provides no functionality.

Accelerometer connection on MK4S and MK3.9S

Original Prusa MK3.5/S

For MK3.5 or MK3.5S, please visit the dedicated guide.

Calibration

The accelerometer is used to calibrate the input shaper parameters. You can launch the calibration from the LCD Menu -> Settings -> Input Shaper -> Calibration.

X-axis

Before proceeding with the next steps, ensure the printer is fully cooled down.

On MK3.9 or MK4, open the fan-door completely before the procedure. Remove the silicone sock, if installed. Identify the part of the accelerometer that is in the shape of the heater block.

Fit the accelerometer to the heater block, by pushing it from the bottom of the hotend. If there is any resistance, do not attempt to push the accelerometer harder, as excessive force might bend the heatbreak.

Y-axis (MK4/S, MK3.9/S, MK3.5/S)

Identify the part of the accelerometer that protrudes from the rest. On the front side of the Y-axis, place the protrusion between the steel sheet and the heatbed.

Results

The results shown on the printer's display at the end of the calibration indicate the optimal input shaping type and frequency found with the calibration.

27 comments

3gfisch

•

on the Core One the short jumper cable is also needed at least my accelerometer is not detected without it, but the manual only tells this for MK4S and MK3.9S.. please update the instructions.

George

•

For the Core One, why put the accelerometer on the bed for the Y axis, since its not a bed slinger?

ChadCarney2001

•

The instructions clearly state that the Y axis is for the mk3-mk4 printers, not the core one.

cupu

•

There is a way to make the pictures for assembly even more fool proof.I've tried to assemble it just by looking at the pictures (which was stupid of me) and I ended up putting the accelerometer in its plastic case before connecting the cable to it. Now I cannot get it out of there and connect the cable.I suggest replacing the pictures with the green arrows to a picture where the accelerometer already has the cable connected to it.

Thank you

Charles

•

I agree, a few extra pictures would not hurt.

tramsgar

•

This guide cannot be found in the "Help", among "Assembly instructions", from the kit's store page or from the general search function. I only found this guide by doing a web search. I would of course suggest you address at least one of these issues! Thanks.

MagnusVesper

•

Wouldn't those screws on the back of the bed be perfect for mounting this?
Using the magnetic bed to hold it down hardly seems secure.