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reprap:rostock:bed_level

Automatic Z-Probe Bed Leveling with Hall-Effect

Calibrate the surface printing bed can be really frustrating :(
Johann in the last commit of the Marlin firmware for Delta Machine has introduced a self-calibration of the bed. N points are measured and interpolated for automatic Z adjustment.
Requires adding a sensor that is able to probe the bed, this is my solution: a Z-Probe Hall-Effect Sensor with autorectraction.

Behavior

The probe is based on a metal small rod with a cubic magnet on the tip. When the rod is in contact with the bed, the magnet approaches to the Hall-Sensor.

On the Bottom another magnet is present for automatic probe retraction :

Finally the complete probe with the sensor:

I used a Hall-Θ endstop which provides a precise adjustable comparator.
If you like to assemble the PCB,is possible to buy only the Hall-Θ PCB.
Here you can find my solution for assembly the PCB with paste stencil created with the RepRap printers.


Bill of materials

Preview Qty. Description
1x z-probe_holder.stl
2x M3x10mm screw
2x 5x5x5mm cubic neodymium magnet
1x metal rod with 66.5mm length and 2.75mm diameter 1)
1x Hall-Θ end-stop



1) cut a long sewing needle

Discussion

, 2013/07/03 23:21

Great idea! How is the rod fixed to the magnet? And how is the calibration started with marlinß I don't find anything about it on his site. Kind regards Michael Kutscer

, 2013/07/03 23:33

The rod is simply attracted by the magnet, a good grip is guaranteed. I'm using a Johann Marlin branch it has introduced the G29 command for automatic bed leveling.

, 2013/07/05 02:06

I don't know if you saw my method. If not, you might be interested in the deployment bar to drop the probe. I haven't finished it yet, but I wanted a way to automatically drop the probe before each print.

http://www.reprap.org/wiki/CrashProbe

BTW, Please excuse the poorly formatted wiki page. It wasn't great to begin with and then recent changes must have mangled the formatting even more. I'll fix it after the holiday weekend.

Now that there is marlin code for probing, I'll make a new mount with a hall switch and give it a try. If anyone in the USA wants 5x5x5 magnets, you can find me on #reprap chat under the most obvious name.

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reprap/rostock/bed_level.txt · Last modified: 2013/07/08 16:43 by marcoantonini