Wednesday, November 3, 2010


I've come to the tentative conclusion that the effective print size is limited to a base of about 2 inches square for colored ABS plastic without a heated print bed. "Natural" ABS is somewhat more forgiving, but the shrinkage of the material is still a significant concern. There are a couple options. I've ordered 5 lbs. of PLA from Makerbot and am looking forward to seeing how this material works out. I do have the heated print bed for the Cupcake, but I've not soldered it together, mainly due to having better things to do than painstakingly hand solder the many surface mount resistors in order to get it assembled.

Here's a picture of Marvin Mk2, a little bot that the MSU Robotics group designed and printed, other than the electronics and a few screws. The Mk1 is documented on Thingiverse, and Mk2 adds a servo to allow positioning of the optical sensor independent of the bot's movement direction. Currently Marvin motors forward until an obstacle comes within 20cm or so, then he turns left until the way is clear. I call it the hacky-sack program. There are plans to add maze solving to his programming, but even with the simplest of control algorithms, folks young and old are fascinated. Here's a test video of Mk1.

We (MSU's McCoy Engineering School) took the Makerbot, robots Marvin and Charlotte to the Austin Science and Engineering Expo and to the MSU Majors Fair and they were all a huge hit. Even though the Cupcake refused to talk to my laptop at the Expo, I think we sold a few Makerbots, and probably could have sold more if they had sent me the marketing post cards that I requested! Ahh, well, with the endorsement of the mayor of New York City, who needs engineering schools, eh? (/wink)