Archive for January, 2010
http://www.protospace.nl/content/protospace-novu-editie-nl-rtl4 -> see the flatpack walker in action on dutch television - it has also been submitted in the unlimited design contest http://unlimiteddesign.nl/en/node/44/6
It is being used in the fablabtruck: http://www.fablabtruck.nl/nl/fablabtruck/lesprogramma.html
Also on idealize (read interview) http://www.idealize.nl/2009/09/udc-2009-edwin-over-simplewalker/
Joris van Tubergen (protospace) talks about the robot in this interview (see vimeo)
It is fun to see how deprivation of material can spark creativity! By setting the boundaries for this project to use ONLY the parts of printers and computer junk, you can - will come up with solutions you otherwise wouldn’t have thought of!
After last week’s enthusiastic post, reality kicked in hard when trying to control the steppermotors. Bottom line: they were by far not strong enough to power the metal carriage (normally they only have to move a plastic printer head) Besides lack of strength, they also lacked resolution. With one step (motor 7.2 degrees) more than one milimeter is covered! This makes it hard to get enough precision for printing parts.
One other problem is synchrony between the two side-axes. The slightest difference between the two motors causes the system to jam. The only way to prevent this is to mechanically link both motors.
It came as a surprise that it is possible to do all this using only the remaining parts of the matrix printers. The gears that were previously used for driving the paper roll have been used for a reduction in the drive train. Superfluous gears normally used for spinning the ink-lint have been used as bearings.
The last two pictures show two optical detectors as end-stops for initialization purposes.
Between the two halve shafts that couple the motions from both Y axes, a temporary meccano solution has been made as flexible shaft coupling. Eventually something will have to be distilled from the printer parts, or I will cheat with an ordered flex coupling.
Some time ago I tried rep-strapping using 5-1/4” diskdrive motors and MDF wood. (see here). The motors turned out to be way too weak, the M5 thread way to slow. Perhaps a larger thread (M12) and some bigger steppermotors can save this evening of work.
In this second attempt I have been using only the parts of three old dot-matrix printers (star LC10) and other computer parts. (I cheated a little bit. So far the extra parts include a big slab of MDF wood and two M8 bolts with washers and nuts)
So far I have build a 3D cartesian robot using the three printers. For the Z-axis I have added the mechanism of a CD-ROM player. Next part will be the motor control (also using the salvaged motor control hardware from the original printers) and an extrusion head (probably not completely from printer- or discarded computer-junk parts)
I’m not particularly clumsy. Ehm.. That is to say.. I’m not particularly clumsy when it is not Early In The Morning, when I have consumed to much drinks containing alcohol, when I’m not paying attention or simply when the bathroom floor is slippery. Anyway, I have this cabinet with very sharp edges and corners. Very sharp. So I put Rubber Duck to the rescue!
This is probably a very very rare issue that needed a special solution. Anyway. If somebody out there find him or herself in the same situation, read on, remember, and know what to do.
If you’re out on a stage, with a folk-band, you have your basic tools, the harp is seriously in need of tuning, but, alas, no tuning key can be found, do this: