CR Touch probe

Started 8th February 2022

The CR-Touch is Creality's version of the BL-Touch 3D printer Z probe, see BL-Touch vs. CR-Touch | Complete Comparison & Accuracy Test

My 3D printer uses an Arduino Mega 2560 and a RAMPS 1.4 board. When I fitted the Creality CR-Touch probe the computer side of the printer began to behave erratically - e.g. LCD display corruption and resets. Online there is a lot of chat about electrical interference (EMI) from the BL-Touch probe and that is plausible, both probes have a big inductor, and my problems occurred as the probe was deployed.

I built a filter and inserted it in the CR-Touch power supply - it made no difference. But as things went wrong again I watched the LCD display fade away and it reminded me of what happens when the power supply voltage is low (when the printer power is turned off but the printer is still connected to USB). Checking revealed that when the probe was deployed the Arduino 5 V supply voltage decreased dramatically. A current measurement showed that the CR-Touch current draw jumped from around 20 mA to 130 mA when the probe is deployed.

I constructed an extra 5 V supply just for the CR-Touch taking its input from the 12 V supply in the printer. Things then worked properly.

Checking accuracy by executing:
M48 P10 v
Gave the result:
Mean: 0.016000 Min: 0.009 Max: 0.023 Range: 0.014 Standard Deviation: 0.005931

I have similar results for various probes.

Opto Interrupter:
Mean: -0.047625 Min: -0.049 Max: -0.046 Range: 0.003 Standard Deviation: 0.000919

Strain gauge:
Mean: 4.384500 Min: 4.370 Max: 4.395 Range: 0.025 Standard Deviation: 0.010943

Inductive (LJ18A3-9-Z/BX):
Mean: 3.003750 Min: 3.002 Max: 3.005 Range: 0.003 Standard Deviation: 0.001250

3D print files:

CR-Touch mount slotted plate designed to bolt on to my E3D v6 Bowden Mount.

CR-Touch mount, David Pilling

A protector/shield/fence designed to stop any bits of excess filament colliding with the CR-Touch. This can be used with the above slotted plate or with the bracket also contained in the OpenSCAD file.

CR-Touch protector, David PillingCR-Touch protector, David Pilling

(Note for Google, this page is about the CR-Touch, or crtouch, or cr touch, and not about crouch)


Page last modified on March 03, 2022, at 01:29 AM
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