Nuts and Volts - January 2008

RESOURCES ■ RoboSpinArt website www.RoboSpinArt.com

■ The Robot Group www.TheRobotGroup.org

■ First Night Austin www.FirstNightAustin.org

■ Dorkbot Austin http://DorkbotAustin.org

■ FIGURE 17. The Robot Group with the RoboSpinArt machine at Austin City Hall.

■ Jonathan Coulton on RoboSpinArt
video
www.youtube.com/watch?v=
WcovKOzvRTc

■ FIGURE 19. The author interviewed by KUT radio.

■ “RoboSpinArt — Concept to Concrete” video www.youtube.com/watch?v= bEKPDoNCyZk

■ “Ink jet gantry — proof of concept” video www.youtube.com/watch?v= 1VzIrBQeaQ0

■ FIGURE 18. The press had fun shooting the spinning colors.

could as quickly as we could trying to make a complete second RoboSpinArt machine from scratch. Rick made a second set of peristaltic pumps (again all by hand) and another spinner for

the bucket in record time. Paul photo-etched more custom printed circuit boards. Many other roboteers stepped in to help with woodworking, decorations, painting, circuit board

■ FIGURE 20. The ink jet gantry.

■ FIGURE 21. A test logo from the ink jet gantry.

preparation, and all the other bits needed to finish the machine.

In the end, we only ended up with two unrealized features: the strobe light sync circuit and the ink jet painting gantry. Though we did get the ink jet gantry mounted

(Figure 20) and in preliminary tests we could get it to print the circular logo (Figure 21), we found we would need a more precise motor speed controller to make sure that the ink jet wouldn’t underwrite or overwrite the text due to variations in speed of the motor that spun the paper. The solution (a feedback enabled motor controller) would require us to rework the shaft sensor to provide the feedback. Unfortunately, it would also require a reworking of the strobe light timing circuit to process this new signal. There just wasn’t time to get it done, so the strobe effect and the ink jet would have to wait.

For all intents and purposes, when the day arrived, we had two fully operational RoboSpinArt machines (Figure 22) ready for First Night. We set up on the day of New Year’s Eve in front of City Hall at 10: 30 a.m. By 11:00 a.m. we had a line of people waiting, so we fired up the machines and started painting. We had a steady line of folks till 11: 30 that night (Figure 23)! The machines ran non-stop (only changing out the operators) for a full 12+ hours, going through well over 1,600 cards without a single system failure. It was an amazing success! Little children, older folks, parents — everyone loved making spin art!