This week the team worked on assembling some of the device's modules, preparing future posts, and revising some of the proposal documentation following the suggestions of the proposal panel.
Team
After meeting with Professor Notash for the first time this semester, the team worked together on revising the Success Criteria, DER, and assembling notes taken from the proposal panel feedback.
The new DER was edited to give a more concise, realistic, and measurable list of core device requirements.
The Success Criteria outlines testing plans for each requirement and defines the manner of verification.
The assembled list of notes below was used as a guide for changes made to the DER and Success Criteria.
John
This week John finished assembling the CODEC breakout boards by soldering the breadboard header pins to the pcbs.
After purchasing some 30 AWG solid wire from skycraft (15$ for 3 50' rolls) he was also able to complete the wiring for two MEMS mics.
In order to make future posts easier, John also created drafts for the future blog entries.
In order to prevent the microphone leads from becoming a potential source of RF interference, John encased the wires for each mic in a shielded jacket. These were repurposed from an old 3 channel audio snake.
Once the wiring was complete, John also ran a preliminary test to ensure the microphones where indeed functional. The preamp circuit was taken from the microphone data sheet. a 1k and 47k resistors were chosen for r1 and r2 respectively
A lm353 op-amp was used. The amp and mic were powered with +-12V and 3.3V DC supplies respectively. The same function generator app that was used in the proof of concept trials provided the signals for this test.
A 250Hz sinusoidal signal was played through the on-board phone speaker and the mic/preamp output was measured using the Velleman PC scope. This test was meant only as a verification of basic mic operation. A more thorough test will be conducted in the future.
Hunter
Hunter was sick for most of the week but was able to update the "Weekly Minutes with the Professor" page, including the following tasks below.
There were some issues with the previous "Time and Effort" page so has been updated using the same app that was used last semester, called "Table Master".
To limit excessive pages the "Senior Proposal" and "Senior Design" tab is no longer a separate page and is simply a drop down menu with the same tabs for the links to each page.
Some pages were blank from the last meeting that required updates, so all pages under the Senior Design tab now have the updated pages. Some of these pages are in drafts and are not uploaded yet. These documents have been submitted to the professor and require feedback before they are updated to the website.
Upon approval of the AC-DC power supply, Pspice simulations were started with the assumption that it will be approved. Linear voltage regulators were tested for the 12V, +-5V, and 3.3V required outputs. Further analysis will be conducted if it this method is approved.
Pspice schematic for first design with all linear voltage regulators is shown (above):
Simulated outputs of each regulator are shown (above) and their relative values are displayed (below), includes the +-24V AC-DC power supply that might be used:
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