change dispenser

As a group we have been assigned a project to design an automatic coin dispenser. The device that we come up with has to be capable of holding 100 U.S. coins. Our goal with our device is to dispense twenty coins in two minutes. The main categories our group will be graded on are things like: speed, cost, ease of use, and ease of manufacturing. We had approximately two weeks to come up with a design, build our design, and get the device to work adequately. The device should be small in size (should fit in a 15’x15’x15’ box), portable, easy to operate, easy to manufacture in mass quantities, and safe. The total budget given to your design team for the prototype is less than or equal to $15. After the group came up with some ideas, we had to brainstorm and figure out which design would work the best. We knew we wanted to use spring-loaded buttons, and we wanted to use our Lego components. After thinking and building different designs with the Legos, we came up with what we felt was the best design for the project. Building four tubes that would hold each coin was part of our problem in the beginning because we were not sure what material to use. Once we found that thin cardboard worked well to make the tubes for the coins, we mounted the coin tubes on top of our device. Basically our first design was the design we went with, but as we went along we would slightly modify it if we felt we could make it better.We had to find out the different coin sizes and thickness. We had build tubes that were long enough to hold 25 coins in each, and the machine itself had to be able to dispense one coin at a time with some sort of button or lever. We found out how big the coins were and how thick each were, and we built tubes that were long enough to hold the amount of coins necessary in each. We built spring- loaded buttons that were attached to our device with Lego components, and our entire device was made up of predominately Legos. The only scientific theory we found useful in the process of building our device was gravity. Gravity is the force we use whenever our coins are dispensed. Limitations and boundaries that are a part of this project are the amount of coins that can be held at one time, and other limitations and boundaries are the number of coins you can dispense at once. Only 100 coins can be held at one point in time in the device, and only one of each coin can be dispensed at a time. The size restriction and price limit is another limitation that we ran into. We got around all of these problems by building a device that was the proper size, using cheap but reliable materials, and we only wanted it to hold 100 coins and dispense one at a time.
3. Solution
We came up with a solution method by making a proper device that could finish the job at hand adequately. The solution we came up with was a device that had differently sized tubes mounted at the top with openings at the top and bottom. The bottom of the tubes are enclosed with the platform the tubes are mounted on. The tubes have slots cut into each side that dispense the coins whenever the spring-loaded buttons are pushed. Once dispensed the coins fall off the edge and slide down the inclined backboard onto the table the device is sitting on. The device is made predominately of Lego components, and cardboard is also used to cover the inclined backboard and to form the tubes. The tubes are held together by duct tape, and we also use springs out of ballpoint pens to make the buttons spring loaded. All of the problems we had from the beginning of the project were fixed with simple trial and error sessions. We never faced any extensive problems, and our first design is the design we used with some slight modifications throughout the building process. The total cost of our project was approximately $2.50. We used four ballpoint pens for their springs in which cost $1.00 for all four, about $.50 of duct tape to hold the tubes together, and we used a cardboard box for the tubes and inclined backboard that cost us $1.00.

Ping Pong Project

As a group, we were assigned to design a robot built of Lego’s. We were given a kit filled with the Lego’s that we needed to build an adequate robot, and the kit also included the programming CD for the computer. Our robot is supposed to follow a line made of electrical tape across the board and dispense the ping-pong balls it picks up a box at the end of the board. We are allowed to use 3 motors, 2 touch sensors, and 1 rotational sensor. Our robot also has size stipulations of 20x20x30 centimeters. The board that our robot is to operate on is 8x4 feet. The objective for our robot is to pick up and deliver the ping-pong balls in a fast and efficient manner. The robot is to follow a black line of electrical tape that is put on a white laminate floor. The line is not straight and has paths off of the direct path made to confuse the robot. The robot is not supposed to stray from the path that goes to the box, and once it gets to the box it is supposed to dump the ping-pong balls in the box. The box at the end of the path stands 15 centimeters tall. Our robot uses three motors, two motors to drive, and one to operate the forklift scoop. There are two light sensors to sense the black line. There is one touch sensor to sense the box at the end and tell the robot to dump the balls out of the scoop. We had to hypothesize as a group how we could build a robot that could get this job done fast and efficiently. Our limitations and boundaries of this project are all encompassed within the stipulations that were given: the rules on size, number of motors, and number of sensors. To formulate and solve how to work around these limitations we rebuilt our robot a few times. We used trial and error to come up with a robot that would work under the conditions we were given.

Robotics Project

As a group, we were assigned to design a robot built of Legos. We were given a kit filled with the Legos that we needed to build an adequate robot, and the kit also included the programming CD for the computer. We are given a board with a large circle around the perimeter and a small circle in the middle, and our robot is supposed to collect the various cans from around the large circle and bring them back to the center circle. We are allowed to use 3 motors, 2 touch sensors, and 1 rotational sensor. Our robot also has size stipulations of 20x20 centimeters. As a group we had to determine which way we wanted to build a robot that we felt would work best under our stipulations and would still adequately finish the job at hand. We used the book from the Lego kit to develop ideas on ways to build our robot. We ended up building our base with directions straight out of the Lego book, and the rest of our robot was built from trial and error. We found many flaws in the first robot we designed, and through trial and error we came up with solutions. First and foremost, our first robot that was designed was a claw-like design, and we could not get the gears to work. We then built another robot that proposed a size problem. The dimensions of this robot was 1 foot wide by 20 centimeters, and our size stipulation was 20x20 centimeters, in which was much smaller than our robot. Our third and final robot was the proper size and had gears that worked. It does not have a claw, it has arm-like devices that act as a guide for the cans it will collect, and it has a touch sensor that when pushed tells the robot that it is holding a can and it then rotates and goes towards the center of the circle.

Bridge Project

Our latest project assigned to us was the bridge. As a group we have to come up with an idea for a struturally sound brige that can hold a total of 20 kg. We are allowed to only use dowel rods and wood glue, and our maximum amount that can be spent is $8. We built a bridge from an idea that was brought about using the West Point Bridge Designer program that our team downloaded. We all came up with basically the same idea for the bridge's structure, and decided to use Pratt Trough Truss idea to construct our bridge. Putting the bridge together did not take that long, but the process in which we had to take to be able to put our bridge together was a little bit time consuming. It takes approximately 24 hours for the wood glue to be completely dry, so that put a damper in being able to build the entire bridge in one day. We ended up building the sides of the bridges, letting them dry, then attaching them on the top and the bottom. Part of the rules for this project was that we had to have a cardboard "road" and a u-bolt attached in the middle of the bridge that we can hang weight off of. So we made our road have a small hill in the middle of it so the u-bolt could be attached properly. The bridge came out very nicely and we are planning on it being able to hold the amount of weight it is supposed to.

Tennis Ball Launcher

As a group we were assigned a project to come up with a device that can launch a tennis ball. We had the stipulations of only being able to spend $8, and the dimensions were 18x18x20. We had a two week assigned period to work on this project and make an adequate tennis ball launcher. We had to make a launcher that could shoot a tennis ball a 25 feet distance, and hit a target that was 2 feet above the ground. It took us many attempts to find the right way to build this machine, and trial and error was our main way of testing. Throughout the process of building this we learned how to work better as a team and what each person could bring to the project. We finished the project and ended up only hitting the target two times out of six, but the project in itself was a learning experience that was quite enjoyable.