Rectanglebear Memo

Team Rectanglebear

Patrick Love

Brandon Rodriguez

Alan Wish

Introduction:

Team Rectanglebear envisions a future that contains an educational model of a combustion engine without requiring combustion. LEGOs were used to construct a central shaft and a portion of the pistons. The piston heads were sketched in SolidWorks and 3D printed. The housing unit was constructed in SolidWorks, laser cut from a sheet of acrylic, and glued together with an epoxy. A DC motor powers the central shaft and a potentiometer allows for analogue adjustments of motor speed. An LCD screen displays the motor speed.

Preliminary Ideas:

Our first thoughts as Team Rectanglebear focused around things we had already seen done. We toyed with the idea of creating a helicopter-like mechanism that hovers at a set distance above the ground, but decided that this sort of idea could go drastically wrong relatively quickly. Spinning blades and crashing expensive components drove us away from this idea. Sticking with some sort of aeronautical idea, we experimented with dirigible concepts. Maybe we could construct a dirigible-based delivery service, or a dirigible-based instrument that plays notes depending on its height. We came to the conclusion that dealing with a floating bag of gas could become a hassle, so we abandoned this idea as well.

Somewhat disheartened, we transitioned from aeronautics to automotive ideas. We could design a remote controlled car, or an autonomous vacuum car similar to iRobot’s Roomba. These projects seemed like they had been done before. We needed some novelty, some originality. That is what Team Rectanglebear is all about. We liked the car idea a lot, but a pre-constructed motor was unsatisfying. That’s when it hit us: A transparent model of a combustion engine. That way, everyone can see and marvel at the ingenuity of the engine.

Design Process:

            Shaft Assembly

As this assembly was made completely out of LEGOs, we could only model the assembly in SolidWorks with the premade parts given to us during Design Lab. This assembly provided a good exercise in mating components. Check out our video of the completed shaft assembly on our blog, www.rectanglebear.blogspot.com . Viewer discretion is advised: the ferocity of the angular bear is contagious.

            Pistons

Since we have a 3D printer at our disposal, we figured 3D printing the piston heads for our project would be fun. Designed by Patrick Love, these stylish piston heads will move vertically inside the housing unit.

            Housing Unit

Made from cut acrylic, these panels are transparent such that the entire motion of the pistons is visible. The back panel consists of our signature, a bear comprised of rectangle cuts, while the side panels consist of bear paws also comprised of rectangles. Two holes were cut from the side panels to allow for the shaft to go through.

            Wiring and Code

A red LED signifies the motor is off. The LCD screen will also display this along with directions of how to turn the machine on. Holding down the button on the breadboard turns on the motor and the LED changes to green as the LCD screen displays the speed of the motor. A potentiometer controls the speed of the motor.

Final Production:

Assembling the LEGO shaft and fitting it within the constructed housing unit was a challenge. Many measurements we originally took on SolidWorks did not transition to the real world. Adjustments for machining error and inconsistencies had to be made in order to get the final piece fitted.

Several days before final assembly, Team Rectanglebear was notified that four out of five top panels had been stolen. This was a hard reality to face, but we held up to our acute reputation. No challenge is too great for a bear with sharp angles. Confident in Professor Sullivan to get our parts re-cut, we continued to brave the challenge.

Wiring proved to be much more challenging than anticipated. Due to the large quantity of wires used in this project, we had to scale up our breadboard. The stock motors from the SparkFun kit had their leads broken off several times during construction, so we had to use a different motor. Compatibility between transistors and this new motor proved to be an issue as well. Altogether, we feel confident that Team Rectanglebear conquered.