BLTouch Sensor - how to change the firmware

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Joined: Sun Dec 30, 2018 9:08 pm

BLTouch Sensor - how to change the firmware

Post by onki » Mon Feb 11, 2019 1:42 am


I have managed some changes on my i3 Alu over the past few weeks.
The control board was changed to a GT2560 (Rev A+) with TMC2208 on X and Y.
I have used Marlin 1.1.9 from this forum which was adjusted to my configuration. This works well.
Then I ordered the BL Touch sensor, printed the holder and connected it according to the Wiki article with the 3 pin connector to Zmax (Pin 32); 2 pin connector to Zmin). Meanwhile I tested to connect the 3 pin cable to the servo PPM port (Pin 11 - close to the thermistor sockets) as shown on another post here.
Hardwarewise they seem to work since The solenoid is acting during init. After that the pin stay on top and the red light is working.
In the BLTouch LCD Menu I can see no action at all.

But most of the firmware changes suggested in the Wiki article are just not existing in the Marlin 1.1.9 code.

Could someone please suggest what changes in the code are required to get the BL Touch done. It is already changed to BLTouch (from manual levelling in the current fw) and I can see the menu. Offsets are set but when I start homing from the levelling menu the touch sensor will not give a signal at Z home position. The pin just stays up so the nozzle is the lowest part.

Any suggestion is welcome.
Best regards

Posts: 32
Joined: Sun Dec 30, 2018 9:08 pm

Re: BLTouch Sensor - how to change the firmware

Post by onki » Mon Feb 11, 2019 4:42 pm


meanwhile I sorted out the hardware problem.

The drawing of the 3DTouch sensor port in this thread ... 66&t=60915 is extremely misleading.
The signal pin is brown although the original color is orange.
After turning the connector 180° (with the orange signal pin facing the inner side of the board) the 3DTouch sensor is working from the LCD menu and also homing works.
At the moment just the levelling fails but this might be due to improper adjustment / disance settings in the firmware.

It would be nice to modify the FAQ article anbd add a comment in the 3D Touch Wiki that on Rev. a+ boards the 3D Touch should be connected to the servo port and not Zmax.

I addition I am still unsure about the TMC2208 drivers. I left all jumpers in place and the drivber seem to work nicely although it is recommended to remove at least one jumper.
If someone could also give an advice on how to setup the motor current (what control voltage for the Geeetech stepper motors).
What about the setting of the Z-drive board since two motors work in parallel?

Best regards

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Re: BLTouch Sensor - how to change the firmware

Post by _kaktus_ » Fri Feb 15, 2019 3:48 am

Hey onki.

I can see that you are evolving and asking better and better questions. Your knowledge and skills grow and you become a professional. ;)

In order to adjust the motor current well, you can do two things, but no solution excludes the other:
  • Experimental control, you modify the Vref to avoid the effect of shifting layers, and the motors do not get too hot,
  • control calculated according to engine parameters.
    In order to do so, you need to know the technical data of your stepper motors. A data sheet is best. But I know that our manufacturer does not make them available.
    So look in the webshop for a description of your motor model and read the value of the rated current. :D

    On this basis you will be able to correctly calculate the Vref value for the nominal current of your motors.
As far as the motors are concerned, in the subforum of my printer I have presented a solution that I have developed.
I encourage you to read the presentation.
On the forum I help to use the rod, I don't give fish.
Geeetech Prusa I3 M201 Dual extruder Mixcolor 3D printer, bought 2017-12-19, already built, in the cognitive and improvement phase
Geeetech filament, ABS only
Geeetech 3D WiFi Module for 3D Printer, bought 2018-04-15, He got a new life, and still lies in a drawer.
Positively frenzied customer of Getech Technology.

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