Task #1 – ball-throwing machine

The ATD 3000 [Attention To Detail 3000]
ATD 3000 was a machine that consisted of four simple machines: 2 inclined planes, a lever and a pulley. The Computer Science Department provided some plywood, a hammer, a rope, nails and a saw as resources for the completion of this task. Other raw materials such as, shoe ‘hoofs’, hangers, carpenter’s glue and a biscuit container had to be secured by the team members to aid the building of the machine.

Design Concepts

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Before the construction of ATD 3000, 2 concepts were developed (see Figure 1 and 2). Although both concepts are similar, they differed in the positioning of the two inclined planes. Both consisted of a pulley, a lever, two inclined planes and a weight. Concept 1 has both inclined planes pointing in the same direction while concept 2 has the uppermost one pointing to the right and the bottommost pointing to the left. After careful deliberation, concept 2 was used because it seemed easier to build considering our level of expertise.

Components of the ATD 3000
Pulley: The Pulley was basically a round object which had a rope tied to a weight object, round its circumference. The Pulley served as the trigger for the machine: releasing the tip of the string spins the round object and drops the weight on the object.

A lid from a biscuit container was used as the round object; cardboard strips were taped on one end of the round object to prevent the rope from slipping over the circumference of the round object. The original edge of the round object together with the cardboard strips acted as two outer strips therefore creating a little ridge in between to prevent the rope from slipping over easily. A shoe ‘hoof’ was used along with some sticky-tape in order to help fasten the round object to a support structure.

First Inclined Plane: The first inclined plane was a rectangular board fastened to a support structure. The first inclined plane receives the ball after the trigger has been pulled and then serves as a runway for the ball to travel unto the next component of the ATD 3000.

A rectangular piece of plywood fastened to smaller squares and a support structure was used to mount the first inclined plane. The smaller plywood squares were used to position the first inclined plane at the desired angle which bests suits its primary ‘runway’ purpose, and also to fasten the inclined plane to a support structure.

 

Second Inclined Plane: The second inclined plane was a relatively longer plane (i.e. relative to the First Inclined Plane) also fastened to a support structure. The second inclined plane is positioned below the first inclined plane and receives the ball from the first inclined plane. Then after, it also serves as the final runway and releasing the ball to the next component of the ATD 3000.

*The raw materials and design used to build the second inclined plane is the same as that of the first inclined plane with the length of the planes and the angles they were position in being different. The second inclined plane was almost twice as long as the first; this was to ensure that there was a more guaranteed release of the ball to the next component of the machine.

 

Lever: The lever was a rectangular stretch of plywood with portions of cardboard cut out to serve as a holder in which the ball would rest safely before being thrown. Beneath the lever were two little pieces of wood used to ensure that the when the force of the weight object is applied to one end of the lever, the whole board does not slip off in any unwanted direction. The lever was balanced on a support structure and was positioned beneath both inclined planes; the two pieces of wood beneath the lever also aided in the levers firm balance on its support structure.

A part of a cardboard box was taped unto the end of the lever that was meant to hold the ball before it is thrown; plywood was used for the entire surface plane of the lever.

Challenges in building the ATD 3000
Unfortunately, after we had built the individual components of the ATD 3000 and were ready to integrate, some of the crucial raw materials (originally provided by the CS Department) were nowhere to be found. The team resorted to calling a resource person for the course (Mr. Yaw: a metal and woodworker) as well as residents in the Berekuso town for raw materials that were no longer available.
For about the third quarter of the building stage, one member out of a two member team had an injury that did not permit him to get involved in more ‘hand intensive’ tasks like nailing and sawing. This slowed down the final building and integration process of the ATD 3000.

Energy Transfer Steps
At the initial state of the machine, the ball has potential energy because of its height above the ground. The weight attached to the string also has potential and elastic energy at the initial state. When the ball and the weight are left loose, the potential energy of the ball is converted into kinetic energy as it slides down. When it falls into the box, that energy is converted into sound and heat. The initial energy of the weight is converted to kinetic and heat and sound as it strikes the pulley.

Wrapping Up
The team found this task interesting and out of the norm of what it was used to. It was a hands-on assignment that required a lot analysis, strategizing and manual labour. During the construction and testing of the machine, the team made a number of observations. The team noticed that a drawn concept could look easy to construct, but during proper construction, a number of other factors come in that complicate things. These factors include the availability of raw materials and the skill of the members of a team. One important lesson throughout the whole task was learning to work as a team. This was particularly crucial because of the injury of one team member, and thus, the task had to be split into sections to accommodate for this. Another significant discovery is about the reliability of a machine. Although theoretically, the machine could achieve the stated objective, it was more difficult practically, because of the number of variables involved. The lesson here is to minimize the number of uncontrollable variables as much as possible.
In conclusion, the ATD 3000 is a machine whose purpose is to get a ball into a box. It is not a robot, because it is not able to sense its environment and act based on its findings. It is just a mechanical device: a machine!

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