Creality 4.2.7 board - BL touch socket for Klicky probe

General Discussion
1

Basic Information:

Printer Model: Ender Pro 3
MCU / Printerboard: Creality 4.2.7 board

Hi i’m searching an answer to this question. Can i connect a micro switch to bl touch socket on this mobo.

there is an filament sensor as alternative and i can use it for that but i want to use that for its main usage ofc

i want to keep z-stop switch for safety reasons. if probe will fail one day it might be useful

This one is my backup printer and i’m trying to find all required information before starting upgrade

Thanks

2

Sure, you can find the schematic here: Creality Board 4.2.2 and 4.2.7 Schematics

Klipper only allows to, EITHER:

  1. Probe used for endstop and probing purposes
  2. Use the endstop for endstop purposes and the probe for probing purposes

Combining both with kind of a redundancy is not possible, so you may as well use Z-min.

3

yes im trying to do 2. just want to use z-limit for safety reasons.

I really didnt get which pins are correct for microswitch and makes it controllable from klipper. i get PB0 is required sensor and i should use pin 1 for that

and pin 2 matches with other endstop sockets if i follow paths on schematics but i’m not electronics expert. still frying board is an option in my mind because i didnt saw any guides for this type of usage

is this correct connection. and it does not matter connected on which side on micro switch right?

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4

As stated before:

  • During probing with the probe only the probe will be active → If the probe fails your machine will crash
  • During homing, only the endstop will be active → If the endstop fails, your machine will crash

So, unless I’m missing something, you will not increase any safety. Rather on the contrary, you will increase the points of failure.

According to the schematics (and without owning or knowing this board):

  • One side of the switch to GND, i.e. either pin 2 or pin 5
  • The other side to signal, i.e. either pin 1 (endstop pin PB1) or pin 3 (endstop pin PB0)
  • The pins have no pull-ups, so you definitively need to activate pull-ups on the pin declaration with a ^ and hope that it is sufficient. Test it if it triggers reliably, otherwise you would need to add a hardware pullup to VCC over a 10K resistor or something like this.
5

• probe will have a z-offset if probe will fail end stop will stop nozzle crashing. end stop will work as secondary check in this scenario
• detachable probe is not in toolhead so end stop switch will save again on any fail while printing or homing macros. Yes end stop is alone on scenario

my guess probe will fail in one day because in every print probe will be triggered at least 18+ (3x3 mesh and 2 samples) + G28 but end stop will be only used on emergency

i dont think i’m capable to add any components or soldering. is there any possibilty to fry board with this connections? i will try 1-2(^PB0) and 5-3(^PA7)

can i just use z socket and connect switches in parallel to same socket in this scenario if you think dealing with BTtouch socket is unnecassary?

6

Again, Klipper does not support this “fail-over” scenario, you are describing. Only one “stop detection tool” can be active at any given time. If it fails, it fails and nothing will save you.

7

lol, ok i guess adding an physical blockage a better method to prevent bed crash. really thanks for explanations

8

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