Progress Report, Week 3: February 22nd
This week we worked on the trying to resolve the issues we encountered last week. To recap, we tried to physically determine the accuracy or plausibility of our device by attempting to observe bead movement caused by vibrations on an elastic membrane. Unfortunately, we didn’t observe any movement.
Our first solution was to replace our second membrane with a visual mechanism that relied on light. An accessible material was the interior of a helium balloon, as it is thin and has a metallic surface. Testing this week revealed that the material was too thick to transmit vibrations.
Professor Liu came at the conclusion of our class time in CMM and suggested looking into angled chambers that may amplify the sound. This would further change our design by minimizing the elastic material to the center to maximize the vibration transmission and by changing the general shape of the device to be like a truncated cone, where the base would be against the skin. Furthermore, he suggested a combination of our bead and light-based visual indicators. Another easily accessible and cheap light-based indicator was a coating of nail polish. This was an alternative to oil, which provides thin film diffraction, but may coagulate of collect away from the center of the device. A nail polish/bead mixture to thinly coat the material would be to get a reflection of the beads while preventing collection to one area of the device. Notably, some of our members are still interested in pursuing the oil effect and the use of the glow sticks to illuminate a mechanism, but the manufacturing might be an issue and thus, we need to consider more details before further pursing it.
Beyond the material of the second membrane, we discussed manufacturing of our device. As we have received our diaphragms, rings, and jars (to house our indicator), our next step is to approach the machine shop to determine how to best combine them. We believe the best option would be to create threads onto the jar that would allow us to screw the corresponding diaphragm and ring on. We will most likely need some help from the mechanical engineering department or the shop to complete this, as anticipated.
With respect to the Arduino, last week the TA commented on our progress report. During the Friday class time, he suggested to try to run the delay and code in parallel to try to resolve the time issue. Additionally, further research into the Arduino revealed that there are hardware timers built into the Duemilanove. With the use of some websites he found*, we will attempt to change these timers with hopes of resolving this issue. Furthermore, we found the millis() or micros() functions, which may give provide us with more insight to the problem.
More digital progress was made with the digication page, as we now have an icon in addition to our logo/banner. Furthermore, efforts were made to fix the table problems encountered when posting the homework onto the e-portfolio. Conversion to an image has temporarily provided a solution.
As with all our progress reports, we encountered another issue with regards to our parts and orders. This week, although marked with progress as we received the plastic containers, diaphragms and rings, our remaining parts have become an issue. Unfortunately, the materials ordered through Nubia’s office were declared "lost". Although eagarly trying to "find" them, we are trying to efficiently use our time to continue with our progress.