Cuphones - Cup Headphones?

Today was kind of interesting for simple side projects. Mark Oscai, a student I work with and regular lab wrecker (just kidding), came in today with something that he had seen in class. I guess one of the ECE 311(Electric and Magnetic Field class) professor, Professor Melloch, did an interesting show and tell with copper wire, magnet, and cup. It would seem Professor Melloch makes a really simple speaker using these things to show how fields work, but I can't really say for sure because my experience with ECE 311 was super boring. Granted, I'm a physics minor and took a more interesting version of the class through the physics department (Phys 330). And by interesting I mean really, really hard. I still had to take ECE 311, but compared to the physics department equivalent it was a breeze.

Anyways, enough boring stuff, here are some of the photos of the materials that were used and just photos as Mark constructed the cup speakers.

As you might expect, the sound wasn't that great so I got the bright idea to add water inside the cup to see if it would dampen some of the noisiness out. The water kind of acted like a low pass filter in the sense that it did in fact dampen the noise, but it also dampened everything except for the muffled bass. It sounded as if you were sitting in the auditorium restroom during a concert. It was pretty interesting.

Here is Mark messing with his magnets and coils to make his speaker work. Mark however is kind of an interesting bird and even though he was able to recreate the speaker working, he still wanted to add some of that Oscai flair to it, which leads us to his revision two of the speaker... or rather... cup headphones.

And just in case you're skeptical of whether or not it works, I have a short video of the device working prior to Mark's... creative headphone revision :)

Sorry about all the background chatter. There were a lot of people really interested in this fun little project. Also, I am sorry once again for vertical videos. I'm not really the best photographer.

BFO Metal Detector Project

 Here is an old project from 2013 when I was still an undergrad at Purdue in ECE 306. The project objective was to combine what we had gone over in the lab course of the semester. I can't remember what all sorts of things we had gone over now, but I do have a lab manual somewhere. I may include it later, but it's not terribly important what we went over specifically in the lab. The main point I'm trying to get at is that rather than the standard full semester's worth of predefined labs, the last month of the semester was dedicated to a project of our(teams of two students) choosing.

Somehow or another, my partner and I decided to make a beat frequency oscillator metal detector. There's all sorts of information about this stuff that you can search up on the internet. I remember referring to this Talking Electronics website an awful lot. I guess I should mention Charles D. Rakes and Colin Mitchell because both are somehow related to the website/information on it.

At any rate, I wanted to include some photos of the project.

The Metal Detector

The metal detector was made from a wooden dowel rod and a wooden plate. I don't remember exactly how many copper windings were made, but to make the Faraday shield I used a aluminum tape. Overall, I think the whole project cost less than $20.00.

The Circuit

 The only interesting thing worth mentioning about the circuit photo is that I used a pill bottle to wrap copper wire around which can be noticed at the top center above the breadboard. For some reason, I remember being rather proud of how symmetrical the circuit was after I had built it for the third iteration.

Here is, for the most part, the finished project on my desk at home measuring... something. Most likely the sound it would make if I had included a headphone jack.

The project on my desk

 The end results for the project were also pretty good. If I remember correctly, the detector could detect metallic objects around 2 inches (about 5 cm) under the my desk. I think I have a video of our success in the lab somewhere, but it's probably super embarrassing so I don't think I'll post it. This project was a lot of fun and I think I finished the course with an A.