PBL Blog Update-2/25/2015

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What does our project do?

Out project is a suitcase powered battery pack charger which then in turn can be used to charge a phone. This is possible by effectively turning the kinetic energy from the spinning wheel(s) to spin our generator. This will create enough power to charge the battery pack. Our battery pack will have a switch which will be able to open and close the circuit that ultimately supplies the phone to charge.

Problems we have run into:

1. Out of all the motors we were provided with, every single one of them did not have a long enough rod that was able to reach the optimal position near the wheel inside the cut-open wheel casing. However, we solved this problem when Mr. Bourque found motor that not only produced the perfect amount of voltage but also had a rod with the length we wanted.

2. The second problem that we ran into was figuring out a way to create enough friction between the rod and the wheel that would efficiently spin the generator. There were three possible ways: a small gear, hot glue, electrical tape, or a combination of both hot glue and electrical tape. We began testing each way starting the the combination. we found that the electrical tape wrapping the hot glue ball on the rod did not provide an adequate amount of friction resulting in a lot of wheel spin on both sides with no electricity produced. We then moved onto to just the electrical tape. Before we even started, we created a hypothesis that the electrical tape would not work because it probably wouldn’t create enough friction, just like the previous test. Like we had expected, it didn’t work. The hot glue was next and it worked very well, surprisingly. But, one downfall was that the wheel wore down the hot glue and after a few minutes of spinning, the hardened hot glue was worn down and ceased to make contact with the wheel. We wanted to test the gear, but we were only proved with a plastic one which would have probably worn down very quickly. Also, the gear hole was too small for the rod. We will keep looking for a small metal gear. For the meantime, we decided just to stick with the hot glue.

3. The third problem is that the generator does not create enough power to charge an iPhone. The voltage requirement in 5V but even when we spin the wheel as fast as we can, the highest we managed to produce was 4.56V. We are still finding solutions to this problem. However, although the results wouldn’t be realistic, we are thinking of doing the tests on a treadmill since it is controlled and can go at high speeds. Another solution to this idea was to attach TWO generators to the wheels. This way the power output could be distributed to not one but two sources. We have decided to use this solution but also the treadmill for test just to be sure.

2. What have we done?

So far, Hannah and I have been building a little but have been using most of our time to figure out the electrical circuit to our build. We have done sone research on how the the rechargeable battery packs work and how to connect the USB cord to the pack. As of now, we are making good progress on both the research and the building.

3. What will we do?

The things we have to do now is to start connecting all our components together. We will also get a start on the research paper.

PBL Blog Update-2/13/2015

1). Where have we been?

We’ve decided what project idea we are going to go with. We are going to build and suitcase powered phone charger by turning the kinetic energy produced from the spinning wheels into electrical energy.
We have also produced a rough blueprint of what our build will look like.

Design: So we are planning to connect the DC generator to the wheel using gears. Then we will hook up the generator to the DC regulator and then to the USB cord to the iPhone.

2). Where are we going?

We are going to first open up the suitcase to reveal the wheels. Then we will use the gears to connect the generator. But before we start connecting the generator, we will first test the generator to get an assessment of how much power it produces.

3). Materials? Who’s doing what?


-One 5-9V DC motor/generator
-About ~1 foot of wiring
-one small gear (~5mm radius) and one big gear (~1 cm radius)
-One expendable suitcase
-A DC capacitor/regulator

I will be the one making most of the blueprints and build while Hannah will be the one who will be getting the materials and helping me build the project.

Electric Motor and Generator

James, Samantha, and Nate’s Electrical Motor and Generator

We make a simple DC motor using and foam cup, some wire, two magnets and two paperclips. We then turned this apparatus into a generator.

Process (For Motor):

We first taped the paperclips to the foam cup. We made sure that the height of both were even so that the coil would stay at a flat angle.
We then moved on to the wire. We first coiled it around a marker and then scraped off the enamel on both loose ends. (The scraping of the wires allow the wire to spin when put on the paperclips.)
We then put two magnets opposing each other on the bottom of the cup (upside down cup). This created one of the magnetic fields to spin our motor.
Then we clipped the alligator clips to the paperclips therefore putting an electrical current throughout he apparatus. This gave the coil a magnetic field and when the magnetic fields of the coil and magnet matched up, the coil spun.
In order to get the coil spinning though, all we had to do is give it a jumpstart.

Process (for Generator):

All we had to do was to use ‘attraction and repulsion’ to create electricity. We manually spun the coil which then moved the electrons back and forth using the magnetic field of the magnets.
We read the output using a voltage meter.

Rube Goldberg Machine

The point of our Rube Goldberg Machine was to bring a phone to your chair without getting up. We were inspired by the idea of not having to get up from the couch to get the remote
First, the person sitting would push a small car down a ramp at a small angle. (This way the car would not have too much potential energy to push the dominos out of the way). This was our first transfer. When the car rolled down the ramp, there was a gravitational energy transfer. Then, the kinetic energy that was in the car was transferred to the dominos to push them down. After the car pushed down the dominos, they fell down which was also a gravitational energy transfer. The kinetic energy that was in the dominos was enough to tip the weight balanced on the dominos to fall down and hit the scissor. This was also a gravitational energy transfer. The scissor cut the string that was wrapped around the metal pole of the zip line keeping the cup with the phone from going down the zip line. After the string was cut, the string unraveled and flew down to your chair. Unfortunately, we were not able to have a third energy transfer because we were short on time. We were going to shoot a rubber band at the car to make it move so the rubber band would be elastic potential but we decided not to. However, we did have 5 transfers.