Week 6

The fifth print of the case was performed this week. For this print, the side rails that gripped the phone were removed and the top corners were cut back. This proved successful, as the phone fits perfectly in the case. It's quick and easy to put the phone in the case, yet it will not come out without the deliberate action of pushing against the lens area from the back. The lens extrusion was also chamfered to eliminate the appearance of the case in the peripheral of the camera. The shape of the case will not be redesigned, as it now functions perfectly. The images below show the fifth case print.

Case print 5 (face)

Case print 5 (rear)

Phone in case (angled)

Phone in case (angled)

 Tests were conducted to determine the amplification abilities of the case. In the first test, the phone was set to full volume, and a sound meter was placed 8.05 inches from the speaker. The phone played 11 monotones, ranging from 262-1976 Hz. The sound level was recorded for each frequency. The monotones were selected based on a normal range of normal frequencies; 262 Hz corresponds to C4, one of the lowest notes played by a typical piano, and 1976 Hz corresponds to B6, one of the highest notes typically played by a piccolo. The exact process was repeated with the phone in the case. Figure 1 below shows the results of the experiment.

A second test was performed to test the musical amplification of the case. The sound meter was again placed 8.05 inches from the speaker. An arbitrary song was chosen, and the same 30-second sample was played from it in each trial. The average sound output was measured over the 30 seconds with the phone at half and full volume, both in and out of the case. The results of this experiment are shown below in Figure 2.

The results of the first test show that, for most frequencies, the case increases the sound output of the phone speaker. This was true for 7 of the 11 tested frequencies. It is unclear why the case reduced the sound output for 3 of the frequencies, but it may be related to the relationship of sound waves and the complex path that they travel inside the case, as well as resonance with the material of the case.

The results of the second test proved the amplification ability of the case for a musical application. At half volume, the case enhanced the sound output by 6 decibels, and at full volume, 9 decibels. Sound is measured on a logarithmic scale, and a difference of 9 decibels is quite significant for this application. The data implies that, the louder the music, the greater the amplification. This test provides objective evidence that the case is effective.

The second dock print was attempted this week as well. The print succeeded this time, though the result was untestable; the slot for the phone and case was too small. The CAD model will be adjusted and a third print will be attempted. The second dock print is shown below.

Dock print 2