User:Epcole/enes100/Sound Powered Phone 2

Link to project.550_EPC team page.

Assign Task1
Build a good inductor

Compare actual work done to Task1
Tried to build a coil and did some induction tests

Week1 Narrative
The first part of making the mic was to make a good coil. I've never built one so I thought it would be a good idea to start simple and understand the process. This coil actually worked better than expected since I didn't use actual magnet wire. I tested this along with a coil from a speaker to compare and the speaker's coil did work better, putting out up to 12mV when it passed through the magnet. The handmade coil was only able to get about 4mV. The other problem was that the aluminum kept sticking to the magnet.

Week1 Peer Review
Go to each team mates weekly summary wiki page. Read their activities and narrative. Then go the associated discussion page. Say something positive on this page. Try some constructive criticism. Add your name and 1sfoerster 13:32, 28 August 2011 (UTC) to create a time and date stamp. Create a new category if another team mate has already commented here.

Assign Task2
Buy some thin magnet wire, Find suitable diaphragm material.

Compare actual work done to Task2
Tested sound powered system using 2 speakers. Visited the National Electronics Museum.

Week2 Narrative
This week I visited the National Electronics Museum in Linthicum, MD to learn a little history on electronics, specifically communications. There were a lot of interesting stuff on display there. There was even a recording of the very first radio broadcast from 1920 that you could listen to. I messed around with a telegraph machine, which was pretty cool too. There were many hands on exhibits that you could mess around with and I learned a lot. They also had a system with an old oscilloscope and what looked like an old speaker box, and when you spoke into it it showed your voice transformed into an electric signal on the oscilloscope. Wish I could get my hands on that box for this project, it was very sensitive and picked up every little it of sound. For the sound powered phone, I tried using 2 speakers connected together to test whether they would transmit sound from one end to another. The first set used the 2 speakers pictured to the right and did not produce anything, not even when I tapped it. I went and bought a pair of headphones to see if I could hear the sound coming out better, with this I could hear the tapping, but heard nothing when I spoke into the speaker.

Week2 Peer Review
Go to each team mates weekly summary wiki page. Read their activities and narrative. Then go the associated discussion page. Say something positive on this page. Try some constructive criticism. Add your name and 1sfoerster 13:32, 28 August 2011 (UTC) to create a time and date stamp. Create a new category if another team mate has already commented here.

Assign Task3
Find how to improve speaker-speaker system.

Compare actual work done to Task3
Tried PVDF film on metal sheets as microphone. Found Sound powered phones to purchase.

Week3 Narrative
This week, I found some articles about PVDF films being used as contact microphones. If you are not familiar with PVDF, it is a piezoelectric film which produces an electrical charge when it is subjected to strain (| more info). I wanted to try to make one of these to see if it can be used for a microphone in a sound powered phone. The film was taped to thin metal sheets (copper 0.07" & Steel 0.02"). The idea is that as the sheets vibrate in response to sound waves, the PVDF film experiences the same strain, which would produce a corresponding electrical signal. There was some response Initially this was tested by just tapping the sheets and the output was pretty large - up to 4V peaks. The response to sound, however, was significantly lower - I only got about 15-20mV and got higher if I screamed into the paper. The other issue I was having was the instability of the PVDF films. The voltage drifted up very fast the longer I spoke into it. I believe this was caused by the heat from my breath (this happened when I touched the sheet also). Connected a speaker to this and tried to move the speaker's diaphragm but could not move it. The PVDF just couldn't generate enough power to drive the speaker's coil. On the other hand, I finally found some sound powered phones for sale and at pretty reasonable prices. Ebay, it turns out has a lot of listings of parts for these and I have actually found a seller who has a full system for sale. | sound powered system. This system according to the seller is pretty much in new condition also.

Week3 Peer Review
Go to each team mates weekly summary wiki page. Read their activities and narrative. Then go the associated discussion page. Say something positive on this page. Try some constructive criticism. Add your name and 1sfoerster 13:33, 28 August 2011 (UTC) to create a time and date stamp. Create a new category if another team mate has already commented here.

Assign Task4
Buy sound powered phone from ebay.

Compare actual work done to Task4
Rationalize differences

Week4 Narrative
Upload photos to wikimedia. Upload video to youtube. Convert all spreadsheets, documents, and presentations to wiki format and create wiki subpage of your page for each of them. Link to them here in a narrative that tells a story. High light the problems (engineering problems) you had and how you solved them.

Week4 Peer Review
Go to each team mates weekly summary wiki page. Read their activities and narrative. Then go the associated discussion page. Say something positive on this page. Try some constructive criticism. Add your name and 1sfoerster 13:33, 28 August 2011 (UTC) to create a time and date stamp. Create a new category if another team mate has already commented here.

Complete Project Page
Follow the "project done" format.

Start Next Project Week0 activities
During this week you will perform the week0 activities of the next project.