Outcome

This was the first project that was built by Vera Schulz and Treat Swarstad was for Garth Zeglin's Physical Computing class back in the fall of 2015.

Narrative:

Our idea was to alter a set of earphones so that they would become receptive to outside noises and then, automatically adjust the sound level output based on how loud or quiet it would be outside. Our device worked better than we expected, but there were some aspects of the circuit, like the speaker that could have been improved. Our idea addresses the needs and safety of individuals who enjoy listening to music while doing active things, as well as those who would like to be more aware of their surroundings. Our project is important because it allows those who exercise in close proximity to traffic to be aware of their surroundings but is also useful for someone working at their desk who wants to know when someone is approaching them. This ambient sound sensor is meant for any utilizer who wants to enjoy music, but also be aware of one’s surroundings. This product is meant to assist in the creation of a safe environment for both the user as well as those in close proximity to the user.

Statement of Objectives:

Our main objective is to create a mechanism that auto-adjusts the volume of a set of earphones to its surroundings. During this process, we would like to create a device that can be attached to already-made earphones. Before embarking on this project we decided to sketch and brainstorm what we wanted to accomplish, this we had no problem with, however, what we were uncomfortable with was the actual mechanics of installing certain elements into the breadboard and optimizing them. For this project we have decided to ignore the final size of our final project as we ultimately would like it to be extremely more compact - something that can fit in a pocket, or clip onto a backpack, ignore the lack of a power supply as well as the fact that our final product is not actually attached to a set of earphones (this was for testing/ presenting purposes). To accomplish our goals we will have to create a working device that adjusts volume based on what is occurring around the user. After creating a device that adjusts sound we will have to connect this to some sort of audio output and test if this product is receptive to all noises or just specific sounds.

Descriptive Text:

We used a basic breadboard to build our circuit and wired it with red and black wires, black always being put into (G) ground. Also, we used two LEDs in our model a white and red one, the red one used in the voltage-controlled resistor. We used various different parts and build our own voltage-controlled resistor which consists of a photodiode and an LED We used a variety of different resistors including one 100 k Ω resistor, a 100 k Ω resistor, and a 47 k Ω resistor. Along with different resistors, we also had a selection of capacitors: (1) 1000uf 16v Electrolytic capacitor, (2) 100uf 25v Electrolytic, and also a 0.1 uf ceramic resistor to limit the current in selected areas. The three elements that were key to our project were the FC-104 Electret microphone LM393, intercepting outside sound, a transistor, BS 170 N-Chan Mosfet, which amplified and switched electronic signals, LM386 N-4 LC amp audio, a speaker 40HM 2w to then, project the sound to the outside. Then, we used a male audio jack to connect the phone to the system. (Note: in the diagram the jack is female).  

Results: What we achieved and what could have worked better

Our limited knowledge and skillset in using the breadboard and schematic technology caused several problems, however, after much experimentation, we were able to create a device that takes in ambient sound and adjusts the user’s music. Even though our project does not fully accomplish our main goals, We do believe we were successful in creating something that adjusts the sound based on what is around the user. The model itself is not ideal in terms of size and comfort but it fulfilled our basic goals for the project. It is not as accurate and advanced as we had originally hoped in terms of design, efficiency, and circuitry- that being said we are still very happy with our “final product.” Even though our product did not fulfill our hope, we still were able to create a system that detects sound through the microphone, and then, that sound causes the music to completely stop. Essentially, our product does stop music when people are close by, however, it does not lower volume in increments it just completely stops it. As the first physical computing project, it was a sufficient and interesting challenge to choose, but there are definitely places looking back, where we could have been more efficient and have found better approaches to our problems.

Vera: Formatting Project Document, Designing Schematic, finishing up writing the project report.

Treat: Designing of the casing of the sound system, wiring of the circuit, creating an outline for report.

Citations:

1. http://www.instructables.com/id/Make-a-Voltage-Controlled-Resistor-and-Use-It/?ALLSTEPS
2. http://courses.ideate.cmu.edu/physcomp/f15/16-223/exercises/electronics/op-amp-level-translation/index.htm
3. https://fritzing.org/