Adventures in CAD

Last night, we focused on finalizing the design for the shooting mechanism. We had a few requirements.

• All actuation must be driven by servo motors
• A single stroke must load the mechanism and fire it
• The shot will be powered by elastic
• The magazine will be gravity-powered
• Must fit the dimensions of a Skittle

Jason measuring the dimensions of a grape Skittle with a dial caliper. Precision engineering.

It took a lot of sketching and headaches to figure out the design, but here’s what we conjured up:

In the barrel, we have a slider with pegs coming off of it so that we can hook rubber bands to it. The slider is what will propel the Skittle out of the barrel. The vertical tube is the Skittle magazine. Below the magazine, we have a trap door. When the slider is pushed toward the back of the barrel, it pushes on the trap door, allowing a Skittle to be released. Then, the trap door and the slider are propelled forward by the elastic. That rectangular area is going to house a servo with an arm on it, which will push the slider backward until it is out of reach, and the slider shoots forward.

We’re RPL newbies, so we lost the feeding frenzy for the Makerbot fleet. We’ll get her printed tomorrow morning and take her for a spin.