Makelangelo Pen Holder Changes
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Let’s talk pen holder mods.
My goals are:
– make it easier to put together and take apart
– make it run even better on bigger surfaces (walls and windows)
– make it easier to put in a penI’ve replaced all the zip ties with velcro tape in my always-changing exerimental model. I’ve also removed all glue. This way it can be disassembled and reassembled many times.
On big walls the pen has almost no pressure at the bottom of the drawing. the machine has to move extra slow down there, and wait longer for pen up/down movements. I think this automatic speed adjustment can be incorporated into the makelangelo software.
Another idea is to stick the pen out more between the pen holder and the paper. This gives more pressure at the bottom of the page, but makes the pen wobble a lot and may be trouble at the top of the drawings. Also if it sticks out more then the servo finger won’t be able to reach the wall, which means the pen can’t lift off the drawing.
I haven’t tried a solenoid instead of a servo. I suspect a solenoid moves so fast that it would crack a window. At the bottom of a drawing it would make the pen holder fly out from the wall.
What say you?
One thing I notice is that, in some cases the pen holder sways (due to pen drag) or rocks (due to the servo) quite a bit due to the two belt screws being above the actual pen. If the pen was centered, this might be reduced, as in:
http://www.gocupi.com/product/gocupi-the-complete-package/
orOops. Just saw your blog post!
I think Harvey Moon attached a stiff wire to the servo horn to gain some distance from the surface. That’s always an option. (Also, could a micro servo be used instead?)
Perhaps mount the servo rotating vertically rather than from the side. If the offset of the servo body is an issue one could always attach a counterweight.
I must say that Dans’ pen holder for the Make 3 is just fine. I tape one American Quarter to the lower left side on the wood and it works just fine. Lines are straight.Everything is balanced. I thought of fiddling around in my Machine shop to try to fabricate some kind of Gondola based on different versions I’ve seen. What’s the point?….if its not broke,don’t fix it.
Sharpie makes a three-pack Super Twin Tip marker. Colors are Black,Red and Blue. They are larger that the usual sort. One end is Fine…the other is Chisel. This…for experienced printers is great information for those larger draws. A nice fat Sharpie. Look for it. I found mine at Staples. It is…the answer.
Are there plans or drawings somewhere for the CD gondola/pen holder? Also….the calibration pattern for the new home position (for make 3+)…what is the exact distance down from top center?
The current M5 pen holder is a laser cut variation on a thingiverse model: http://www.thingiverse.com/thing:798076
ymmv.
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