Grove sensors are a nice way to connect sensors (and displays) to Arduino or Raspberry Pi controllers. If you need to fix such a sensor at a Lego technic model, you may use this mount, based on my Lego I-Beam script for OpenJSCAD (see http://www.thingiverse.com/thing:1345474).
Potential Solutions for Difficulties When Printing
Printing this frame (or any Lego beam) on a real 3D printer may reveal some practical problems which have nothing to do with the original modeling of that beam. Nevertheless, there are a few additional modeling parameters which can be used to solve some of these problems.
extraWidening can be used to widen the beam holes a bit: since vertically printed walls appear to be a bit "rough" because of the slice structure, Lego pins might become difficult to insert or remove - in that case, some widening of holes may simplify pin usage. By default,
extraWidening is set to 0, but you may increase it slightly, e.g. up to 0.1
massive: by default, the resulting I-Beam is built based on a "lightBody", which looks like the Lego original, but may be difficult to print as it contains filament "bridges", i.e. parts which do not lay flat on the printbed but start a little bit above. If it turns out, that your printer is unable to print those "bridges" properly, simply change the
IBeam invocation to
zFactor should usually be set to 1.00 - unless your printer has been poorly configured and needs some scaling in the x, y or z direction. By default, all these factors are set to 1 - in this case, the scaling step is completely skipped, in order to speed up the script a bit. You may, however, try to increase these factors slightly, e.g., up to 1.03
Cleansing after Printing
Printed parts usually need some "clean-up" after printing - this especially applies to objects which need to fit other parts.
Personally, I usually take a Dremel 453 ("Chain Saw Sharpening Stone", really) - rotating slowly(!) - to clean the Lego drill holes, but also the "steps" within these holes (especially the lower ones, i.e. those closer to the print bed, as they had to be printed without support structures)
Washing the cleaned parts with pure water removes the dirt and reveals result which can be easily used in combination with standard Lego technic components.