BTT/BIQU microprobe on QIDI Q1 pro

This is :

• a support for BIQU/BTT microprobe to adapt it on the QIDI Q1 pro.
• a description how to install it on the printer
• a description of the modifications in the printer.cfg and gcode_macro.cfg files
   

The QIDI levelling system works fine but it is very very slow.

• inductive probe is not absolute as it may drift with temperature.
• to cope with this issue, QIDI performs an automatic zoffset computation based upon the piezzo sensors under the bed (they give the zero) and allow to calibrate the z offset measured by the probe
• however as the zero is given by a direct contact of the nozzle on the bed, the nozzle has to be clean hence the very long wipe on the flimsy cleaner...
  Even if it is working fine 98% of the prints, you may get failed prints when the noozle is not perfectly clean or maybe when the piezzo sensors return a so so result...

The BIQU/BTT microprobe is a very accurate (probably optical) sensor which releases/retracts a pin in charge to trigger the probe signal when in contact to the bed.
With this, once the z-offset is (manually) calibrated it will never change and the probe will only measure both position of the bed and the surface of the bed.
The accuracy and repeatibility of the microprobe allow to perform only one measure at each point of the grid

see it working: https://youtu.be/pKfJ818jIDk

mechanical part

The part must be printed with a heat proof filament (at least ASA or ABS...)
It is screwed with the rear screw of the genuine QIDI inductive probe and with the front screw of the hot end fan.

As there is very little room under the head's cover, you will need a flat head 2,5mm x 18 mm screw to replace the fan's one. Keep and use the grover washer from the QIDI fan screw...

The other screw is a M3. You can reuse the genuine inductive probe's one as long as you shorten it either with a dremel or simply using 2 nuts to virtually shorten it.

To install the probe on the support, just use two M2.5 screws provided with the probe and self tap them inside the holes.

Be sure thickness of the support is OK, manually test deployed/stowed positions to check the pin tip is lower/above the nozzle tip.

electrical connection

The microprobe has to be connected at the rear of the extruder. 

• Turn OFF the printer.
• Remove the front cover, 
• remove the back cover. 
• Unplug the inductive probe (top left black connector).

Before plugging the microprobe you have to reshuffle the BBT connectors. 
With a needle, gently bend up the black tabs and pull the wire and pin.
Then insert back the pins according to the schematic and picture.

Note that the second black wire must  be insulated with some heat tube.

Check again the connectors :

• RED, BLACK, WHITE connected to the upper black connector RED at the left.
• Only YELLOW connected to the upper pin of the orange connector

You can screw back the covers.
 

configuration

There is some job to do at that level. I'll explain main differences and give you my configurations files in order to simplify the process.

Files are modded from the V4.4.21 QIDI's ones

printer.cfg

pin GPIO11 usually used for the option extruder fan will be dedicated to the prob deploy/stow
Should you need this optional fan, please connect it directly to +5V and ground to release the GPIO11_

a [probe] section has to be defined to replace both the [smart effector] and [qdprobe] sections
 

; microprobe  (replaces smart effector and qdprobe )
[probe]
pin: ^!gpio21
x_offset: 24
y_offset: 10.0
z_offset: 1.14 #must be configured individualy
speed: 5
samples: 1
activate_gcode:
   probe_deploy
   G4 P500
deactivate_gcode:
   probe_stow
deactivate_on_each_sample: false

[output_pin probe_enable]
pin: gpio11
value: 1
     

[gcode_macro probe_deploy]
gcode:
   SET_PIN PIN=probe_enable VALUE=0

[gcode_macro probe_stow]
gcode:
   SET_PIN PIN=probe_enable VALUE=1

; replaced by microprobe
; [smart_effector]
; pin:U_1:PC1
; recovery_time:0
; x_offset: 17.6
; y_offset: 4.4
; z_offset: 0.000001
; speed:5
; lift_speed:5
; probe_accel:50
; samples: 2
; samples_result: submaxmin
; sample_retract_dist: 5.0
; samples_tolerance: 0.05
; samples_tolerance_retries:5

; replaced by microprobe ici est defini QIDI_PROBE_PIN_2 QIDI_PROBE_PIN_1 donc on ne peut plus utiliser les piezzo
; [qdprobe]
; pin:!gpio21
; z_offset:0.000001
 

the, now useless vibrate code has to be removed:
; vibrate_gcode:  ; removed for microprobe
;     Z_DOUDONG    ; removed for microprobe

===> MIND THE Z_OFFSET !
This line in the printer config has to be edited to fit your printer.
It is safe to start with a Z_offset set at 0. The head will fly too high…

replace : 
   z_offset: 1.14 #must be configured individualy
by
  z_offset: 0 #must be configured individualy

That is !

gcode_macro.cfg

That's the hardest part as there are several simplifications. Open the provided file , the modifications are commented and described.

Basically main mods are :

• remove useless macros : test_zoffset, move_subzoffset, get_zoffset, save-zoffset, set_zoffset
• it is better that CLEAR_NOZZLE and CLEAR NOZZLE_PLR don't move too far to the left because the microprobe is quite low and be damaged if it hits the wiper device… so keep X min at 77
• cleaning perfectly the nozzle is not needed so the CLEAR_NOZZLE macro has been drastically simplified and is done only at filament temperature just to clean poteital oozing before print.
  Note that the bed mesh levelling can still be done from the LCD. It requires the CLEAR_NOZZLE macro to send some messages to the console; so keep them !
• PRINT_START is heavily simplified with the following logic:

1. set the chamber temperature and don't wait
2. preheat the hotend 80° bellow the filament temperature
3. heat the bed and wait for the temperature to stabilize
4. then perform HOMING and BED MESH (in case there is somme oozing, the filament will be soft and will not prevent the pin to go in contact with the bed)
5. goto to the wiper parking position , finish heating the hotend to the filament temperature, finish heating the chamber (if needed) 
6. then clear the nozzle
7. goto to front left position and start the print with the usual priming pattern
   
    

initial testing

Now that everything is installed, plugged, configured it's time to test. I know you're nervous :-)
You can do the following steps :

• switch ON the printer and you will see the pin being released/stowed 5 times. This is the proof the probe is working!
• wait the probe goes in stowed position 
• check your FLUIDD page it should look like this
  
• play with PROBE_DEPLOY PROBE_STOW macros the pin shall move. After each command send a QUERY_ENDSTOPS command and checj the Z status. It shall look like this.
  
  
  If OK you're ready if not you did something wrong…

then home your printer, heat the bed and the nozzle. Clean the nozzle (manually). Move the Z slowly up and with a sheet of paper calibrate your z-offset.
type the z_offset in printer.cfg

z_offset: 1.14 #must be configured individualy
 

Bottom line

do not do this mod if you don't feel confortable with it. I cannot be taken for responsible if you damage your printer
 

(credit to k3d who gave me the idea: https://k3d.tech/printers/qidi_q1_pro/)

(credit to the BTT GitHub for the BIQU microprobe STL)