The Rube Goldberg Machine
Introduction
Our class had been tasked with creating our very own Rube Goldberg Machines. Before the lecture introducing this assignment, I had never known the name for this chain reaction type of machine. I had seen only a few in viral videos that were carrying out a simple task.
Materials
The first step for creating a Rube Goldberg machine is to gather all of the materials you think may be useful for the machine. I went foraging for ‘suitable’ materials all over my house, but I came up a bit short. However, I was willing to improvise with what I had.
From the many, many Youtube videos I had watched, trying to find some inspiration, I found a very common component that people use. These were toy car race track channels. I unfortunately did not have access to anything of the sort, so I improvised. I made several channels out of cardboard, big enough to support a ping pong ball.
The Machine
Research
Once I had an idea what materials were available to me to build this machine, I researched the most common elements found in Rube Goldberg Machines. These elements included, incline planes, pulley systems, domino effects and release mechanisms, to name a few.
The Simple task
After brainstorming the elements that would be a part of the Rube Goldberg machine, I tried to think of a simple task that would be executed. I chose to use a pulley system to pour dog food into a bowl which would feed my dog, Kirby :)
The robot
One of the requirements for this assignment was to incorporate the Tumbller robot into the machine. I chose to have the robot start the chain reaction machine by pulling a string. One end of the string was tied to the top of the robot and the other end was tied to the top of a small box. The string was draped over a tall lamp, so that when the robot moved forward the box would rise and release a ping pong ball.
The image below shows the code I wrote and uploaded to the Tumbller. I used the same Arduino file as I did for the previous assignment but I just changed the void loop function. The command tells the robot to wait for 7 seconds once it is turned on. This allows the robot to balance and to give me time to start recording. I tested out different speeds with the robot moving forward, I uploaded the speed of 20 but I discovered that that wasn’t near enough speed. At this speed the robot did not have enough momentum to lift box, so I updated the speed for each trial and finally settled on the speed of 60, which was enough to lift the box up, releasing the ping pong ball.
The connected ramps and tunnel
I had made a sketch of this element before and decided to recreate it. I collected some jigsaw puzzle boxes and positioned them at an angle so that when the ball was released, it would find the path to the tunnel. After testing it out, I figured I had to place the ramps at an incline so that the ball wouldn’t get stuck in the middle. I also had to add borders at the bottom because the ball was at risk of rolling off and missing the tunnel.
For the tunnel to the ramp board, I made a cardboard channel which was connected to a cardboard toilet roll. I made this to transport the ball from a horizontal surface to a vertical one.
The ramps and domino element
I found a big sheet of cardboard and decided to attach the cardboard channels I had made onto it. I taped the channels onto the board at certain angles so that the ping pong ball travelling down the board, would do so successfully. I wanted the ping pong ball to set off a chain reaction, so I lined up Jenga pieces at the bottom of the board for the ping pong ball to knock over. These Jenga pieces acted like domino pieces and knocked over stacked cards, which in turn, knocked over CD cases and then hardback copies.
The collision
The domino element was used to trigger a collision between one of the hardback copies and a roll of sellotape which was placed at the edge of a box. The idea was that the copy would knock the tape roll so that it would fall into a box which was part of a pulley system. I chose the sellotape roll so that it could travel from one side of the box and then fall off the other. The weight of the sellotape was an important part for the pulley system to work.
The pulley system
The pulley system consisted of a box tied to one end of a string and the other end connected to a box holding the dog food. The dog food was placed in the middle of the bowl, while on the other side of the table the box was hanging, waiting for the roll of sellotape. Through testing a number of different items, I found that sellotape was heavy enough to weigh down the box, lifting up the dog food and spilling it into the bowl.
I initially tried using a plastic cup to deliver the dog food to the bowl. However, after punching a hole through the middle, a split formed up the whole cup, meaning the string could only be tied to the top. I needed the string to be connected to the box towards the bottom, so that the box was lifted from the bottom, causing it to tip over, pouring the dog food out into the bowl. To remedy this, I made my own little box out of cardboard and poked a hole through the cardboard towards the bottom and fed the string through and tied a knot to secure it.
The final video
Even though it was a very tedious operation to set up, especially the domino element, the contraption ran quite smoothly. The simple task of feeding my dog, was carried out successfully, even though he did not eat any on camera due to him being camera shy. I can assure you, once the phone was put away, he didn’t leave a single crumb behind!
