Hall effect endstops on repstrap Morgan.

Hold your idea in your hand Forums Morgan Builders forum Hall effect endstops on repstrap Morgan.

This topic contains 6 replies, has 4 voices, and was last updated by  sam_s 5 years, 9 months ago.

  • Author
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  • #1691

    Diode
    Participant

    Hi All,

    I am currently testing and tuning a “Repstrap” version of Morgan and had problems with inconsistent operation of the Z end-stop. The final position of the bed varied after going to Z0 following homing.

    I am using A3213 hall effect devices which are cheap but very sensitive and uncritical of magnetic pole direction. The problem was completely cured by connecting a 0.1 uF capacitor between the Vdd and ground pins close to the device (as per the recommendation buried in datasheet detail). Apparently the A3213 and similar chopper-stabilised devices can generate their own electrical interference unless such a bypass capacitor is fitted.

    For the curious, I don’t have easy access to a working 3D printer hence the repstrap version. The only printed parts are in the extruder which I bought as a kit. The drive column is fairly conventional – but the drive wheels were turned from MDF (on a drill-)and the arms are made out jointed aluminium tubing. I plan to post some details & pics once the print quality is OK.

    Diode

  • #1693

    Quentin Harley
    Keymaster

    I would love to see your Strap Morgan. I thought about doing something similar myself, but after getting access to a 3D printer, the design really got well under way. The main problem is that you spen so much time to make parts manually, that it is hard to chuck them and make new ones, slowing progress considerably. Much better if you know that what you are making is actually going to work!

    Thanks for the tip… I will look it up.

    Q

  • #1701

    Diode
    Participant

    Here are some pics of my “Repstrap” version of Morgan…

    Laminated MDF drive wheels

    Arms made from 25mm and 16mm aluminium tubing.

    “Strap” uses 25mm and 16mm aluminium tubing for the drive column and for the arms. The z axis drive uses plain 8mm threaded rod instead of Alpen SDS drill (unavailable locally) for the z axis. Today I ironed out a z-wobble problem by adding a bracket just above the drive wheels. This holds a flanged bearing to take the platform load and allow use of a flexible motor coupling at the top. Electronics is Ramps 1.4.

    Diode

    Diode

  • #1702

    Quentin Harley
    Keymaster

    This. Is. Awesome.

    Respect!

    I will feature it on the front page if you don’t mind…

  • #1703

    Whiskey
    Participant

    thumbs up ! WOW …

  • #1710

    Diode
    Participant

    Hi Quenton,

    Yes by all means – use the info in any way you like – especially since it is just a variant of your brilliant design.

    Diode

  • #1712

    sam_s
    Participant

    Amazing.

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