A Change in Greatness

An Alteration in Design

The design we had modeled final has been printed, after much technical difficulties. However, only half of the design was successfully printed until it was removed from the printer without our knowledge. When lining up the 3D printed case with the actual phone, it was noted that there was a large disparity in size. The Samsung case that was used as a template was too small and the plastic used in the 3D print was too rigid for the phone to actual fit. However, it was also noted that the type of material that was used for the printing was not the best fit for this particular design, due to how weak some of the joints were.

As a result of the numerous problems we have encountered with 3D printing, we have decided to manually fabricate the system. The group has decided to simply purchase a low cost Samsung phone case, so we do not have to worry about sizing again, and will will attach a separate system to its back. This separate system's material hasn't been decided on concretely yet, but it will likely be made out of metal and will house everything except for the external battery the solar panels pour energy into. The battery itself will be attached to the outside of the system in order to decrease the awkwardness of carrying a phone and so the phone plus the system doesn't extend down to far. 

Other than the mechanical problems and changes that have occurred there is also some electrical changes that have occurred. Recently accumulated a decent amount of data using multiple different solar panel systems and a light meter: 

Data Collected

Light Level (in Candelas or Steradian/m2)

45°: Toward Sun	Flat	45°: Away from Sun
1,028,814	541,962	69,491

Voltage and Current Readings (in Volts and Amperes)

1 Panel in Series	45°: Toward Sun	Flat	45°: Away from Sun
Voltage (V)	1.15	0.900	0.810
Current (A)	0.45	0.30	0.02
2 Panels in Series	45°: Toward Sun	Flat	45°: Away from Sun
Voltage (V)	2.26	2.21	1.94
Current (A)	0.40	0.30	0.03
3 Panels in Series	45°: Toward Sun	Flat	45°: Away from Sun
Voltage (V)	3.44	3.35	2.87
Current (A)	0.41	0.26	0.03
5 Panels in Series	45°: Toward Sun	Flat	45°: Away from Sun
Voltage (V)	5.71	5.69	5.05
Current (A)	0.42	0.32	0.05

As you can see by the data, when we had 5 solar panels connected in a series circuit they produced a current around what we would expect, but also produced voltage that was much higher than what we expected. As a result of this voltage surplus we have decided to take away two of the solar panels and hook them up to the step up to achieve the 5 volts we need, because that would be much simpler to create, mechanically speaking. 

The next step for this project will be to fabricate the system out of metal, which will occur tomorrow, and to finish setting up the slightly altered electrical system complete with the step up and battery!