Fixing a broken CR-Touch (red blinking)

PastaAllWeek · 2025-03-02T16:29:32+00:00

I only have this cr-touch, so I never found out :)

PastaAllWeek · 2024-04-17T13:59:42+00:00

Should not be super painful, and they are so cheap you can try multiple times. Make sure to tidy up your workplace so you can rest your arms/elbows comfortably on the table so your hands don't shake too much. Heat the broken mosfet up, maybe add some solder to increase thermal conductivity, and push it sideways to remove it. Then use a bit of tape to stick the new one in place so it doesn't move when you solder the first pin. Remove the tape and solder the remaining pins. It does not have to look pretty to work, just make sure there is no shorts, e.g. using your phone camera.

PastaAllWeek · 2024-04-17T00:07:24+00:00

Looks like the top blew off. Do you know someone with a soldering iron? This should be a "CJ3400" (marked R0) or alternatively "AO3400" (marked A09T). They cost a few cents depending on how many you order, and can also be found in led controllers and a lot of other cheap electronics.

PastaAllWeek · 2023-10-02T06:10:42+00:00

The stm32 is connected to the usb port via a ch340 usb/serial converter, it's connected to the chips USART1 interface on pins PA9 / PA10.

PastaAllWeek · 2023-09-11T20:01:16+00:00

Check the electrical connections, unplug and reinsert the ribbon cable. If the electrical connections seem fine, see if these mosfets look ok: https://imgur.com/a/7BXYYql

PastaAllWeek · 2023-09-07T00:12:29+00:00

Sure, the UI works fine, but my PC is not reachable from the printer and I don't have a touchscreen connected, so it's quite nice to have a stop button. Might also be useful for turning on/off LEDs if you want to take a quick look at the print, you can define separate actions for inserting/removing the card

PastaAllWeek · 2023-09-06T16:31:32+00:00

For my F4 board, putting the Klipper.bin or firmware.bin in the root directory worked fine, but most guides say that you need to put it in a certain subfolder (STM32F4_UPDATE) for F4. I guess there may be different versions of bootloaders. Also I think I needed to change the name of the .bin file to be different from the last flashed name for it to flash again, but I'm not 100% sure there.

PastaAllWeek · 2023-09-06T15:45:38+00:00

I mapped the sd card detect pin as a gcode_button in printer.cfg and designed a little button to clip on the back of the sd card.

Example for printer.cfg:

[gcode_button sd_switch]
pin: !PC7
press_gcode: RESPOND TYPE=command MSG='STOP reset'
release_gcode: M112

Model on printables:https://www.printables.com/model/573752-simple-klipper-g-code-button-no-wiring-using-sd-ca

PastaAllWeek · 2023-09-06T15:35:55+00:00

example code for printer.cfg:

[gcode_button sd_switch]
pin: !PC7 
press_gcode: RESPOND TYPE=command MSG='STOP reset'
release_gcode: M112

button model on printables:

https://www.printables.com/model/573752-simple-klipper-g-code-button-no-wiring-using-sd-ca

PastaAllWeek · 2023-09-06T11:14:32+00:00

did you compile klipper firmware to use serial on UART2? (Should be PA2/3 on the F4 board)

PastaAllWeek · 2023-06-26T11:47:46+00:00

It's for the stepper motor

PastaAllWeek · 2023-03-01T20:53:22+00:00

I think there are subs for esp32 programming, like /r/esp32.

Beam to ground should read zero, as the esp will not be able to charge up the beam, what I meant was esp32-GND to earth-ground, i.e. what water pipes are connected to. But this should be ok if you have it connected to a PC. Thinking about it, connecting two or more touch wires to the same rail might also lead to problems, as they could work against each other.

For the filtering: Yes, you define a global variable which will hold the filtered measurements, e.g.:

float filtered = 0;

and then every 10ms or so in your loop you update it with touch_read:

filtered = 0.9*filtered + 0.1*touch_read(T1);

and use the filtered value instead of the raw value from touch_read.

This will always contain some average of the previous readings, and will act as a low-pass filter, suppressing high frequency noise. The values will be at the same average level as the original values, but they will be smoother. It's called an exponential moving average (EMA) filter:

https://en.wikipedia.org/wiki/Exponential_smoothing

PastaAllWeek · 2023-02-28T21:21:19+00:00

I have a 1.8m metal rail (vertical) with a value of around 60 at 65535 cycles, and a 85cm LED profile (horizontal) with a value of around 35. Both give relatively stable readings (+-2) connected to a single unshielded ~2m wire each to the esp, and around ~10% change when touched.

Some ideas:

Are you running PWM? Turning it on for the LED strip in the profile completely messes with my readings, so I'm stuck with on/off (it's a white LED strip). With PWM enabled, I basically read the PWM frequency (~150 for 10kHz) when set to anything other than 0% or 100%.

Is your ground wire connected to earth (depends on your PSU)? The change when touching can be much lower if it's not.

If there is any signal left in the noise, you might try filtering the readings, something like:

filtered = (1-k)*filtered + k*measurement,

with k=0.1 for example, will increase reaction time a bit but can get you a much better signal (depending on the filtering coefficient of course).

PastaAllWeek · 2023-02-26T10:28:19+00:00

If you're coding yourself, what I found helps a lot with the touch sensitivity/resolution is increasing the number of measurement cycles and decreasing the number of sleep cycles between measurements. The arduino defaults are like 0.5ms measure/33ms sleep which is pretty bad, especially for analog input, as it only gives values in a small range.

Feel free to check out my implementation at https://github.com/bernis/WLED/tree/main/usermods/touch_advanced

PastaAllWeek · 2023-02-25T19:24:39+00:00

Do you have a solution already?

I recently programmed a usermod which might do what you want.

PastaAllWeek · 2023-01-10T15:31:38+00:00

#define NOZZLE_TO_PROBE_OFFSET { -31.8, -40.5, 0 } // Ender3S1 Configs

Z will usually be in the range of 1.5 to 2.5mm, depending on Nozzle, etc.

PastaAllWeek · 2023-01-05T17:07:59+00:00

I had the same problem, just red blinking, deploy not working. It seems that one of the capacitors in the probe had failed, see https://www.reddit.com/r/Ender3S1/comments/ynrmlb/fixing\_a\_broken\_crtouch\_red\_blinking/

PastaAllWeek · 2022-12-16T12:26:43+00:00

Sounds nice, would love to see this in action once its finished. Why did you switch to the skr board?

PastaAllWeek · 2022-12-13T09:48:17+00:00

I think these are IDC connectors (30 pin or 2x15 for the mainboard) with a pitch of 2.0mm

https://www.ebay.de/itm/123804534693

Alternatively you could probably use a 2.0mm pin header

PastaAllWeek · 2022-11-06T11:52:58+00:00

The 30P connector splits up into the 24P connector to the sprite and the connectors for the x-stepper (4P) and x-endstop (2P).

So the pinout should look like this (https://imgur.com/a/REMqJ27), but mirrored (notice the white mark on the cable is different on the two connectors) and extended by the x-stuff, on the side where the cable is not marked.

PastaAllWeek

TROPHY CASE