Week 8

The components of the phone charger were printed from a 3-D printer. The pieces did not fit together properly and were taken to the machine shop to see if they could be fixed. At the machine shop the interior piece was milled down so the interior diameter was larger. In addition, a small hole was drilled into the end of the piece to release excess air pressure that would accumulate in the tube. Unfortunately the interior piece could not be corrected enough to be usable and had to be remade. This was a major setback to the completion of the project. A USB port was obtained and connected to the circuit. The last step in order to complete the project is to finalize the calculations to determine the proper amount of coils needed to produce 6 to 9 V. This will be calculated and tested in the upcoming week.

Figure 8

Figure 9

Week 7

The full circuit, including the capacitors and diodes, was put together and soldered. It will be able to turn the AC current produced from the magnet passing through the coil of copper wire to DC current which is required to charge a phone. The circut is set up in a diamond shape and on the end furthest from the capacitors the anodes are connected from two diodes and on the opposite end the cathodes are connected (see Figure 6). In between thee two ends the anodes and cathodes are connected which allows the current to flow in a sort of one way gate through the diodes. The capacitor's positive ends were soldered to the cathodes of two of the diodes in the rectifier (see Figure 7). The negative ends were then soldered togther. The circuit will be tested over the next lab and the casing design will be completed as well.

Figure 6

Figure 7

Week 6

All of the resistors, diodes, capacitors, and magnets have been acquired. The full wave rectifier will be set up in this weeks lab. The rectifying circuit will be tested this week in order to determine the actual voltage output of the circuit. The voltage will be tested using an oscilloscope which will be used to find the peak voltage of the rectified sine wave that will occur. The full construction of the shake phone charger will take place this week.

Week 5.5

Since the last update, the group has met twice to work on the project. They first met on Thursday May 3rd and took a trip to RadioShack to purchase a diode and a capacitor. They next met on Sunday May 6th to work on updating and revising the blog for the upcoming week. The final design of the rectifying circuit was decided upon (Figure 5). The rectifier will change the alternating current made from the magnet passing through the coil of wire to a direct current. The charge created by the current can be stored in a capacitor (see References 1).

Figure 5

Week 5

This week we started the calculations to determine certain variables that are necesary to making a working circuit that can generate the correct voltage and current. The main equation used was Farraday's Law (Figure1) which states that voltage generated is equal to the number of turns mulitplied by the magnetic flux over the change in time (see Reference 5). Because we know the voltage that we want to generate is between 6-12 Volts and the magnetic flux for the magent we plan to use is 1 Tesla (T) and the change in area over time is approximately 0.2 m^2/s we were able to calculate that we need around 45 turns of the coil to generate a voltage of 9 V. We also now plan to travel to Radioshack to purchase the necessary materials like diodes, and a capacitor to be able to create the circuit.

Figure 4

The equation used to determine the voltage generated is as follows:

V=N*B*A/t

Where V is the known voltage, N is the number of turns of the coil of wire, B is the magnetic field strength, A is the area of the coil of wire, and t is the time taken for the magnet to pass through the coil.