Visual Beats Log

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Revision as of 13:45, 28 October 2016 by Ligao (talk | contribs) (10/28/2016)
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Welcome to the Log!


This week we established our schematic of visual-beats and has worked on the proposal. Instead of simply generating frequencies from speaker/amplifier, we decide to connect a xylophone to the Arduino board. So that we can see different patterns generated from different xylophone musics. We talked with our TA, Will about the theoretical feasibility and other potential improvements.


We are in the process of completing multiple sketches and finalizing our plan before purchasing items. We are working on laying out a detailed process of the piezo signal transmission from GarageBand to the Amplifier and the figuring out the computation of the Kirchoff-Love Plate theory into 3-D Models. We might be choosing to use a smaller speaker, but need to do more research in order to understand the level of sound we will be working with. We have considered using surface transducers/oscillator motors, but since we would rather have an output that plays music, we chose to stick with an optimal speaker. Understanding the audio engineering to how speakers work is a must before we begin building anything.


We spent this week "coming down to Earth" with our ideas and decided to let go of the xylophone as our project is already dense without it. Instead of using a speaker and having to hassle with connecting its coil to the plate, we found an object called the Exciter which is an electromagnetic coil used to impact sound on plates. This caused our prototype model to be rearranged with new materials as well, which you can view from our wiki page.

Our plan with the Arduino is to connect a DAC to the Arduino board so the digital signal would be converted to analog signal. Then we "amplify" the signal by connecting an amp to the DAC.


For now, we've decided to place our plate/speaker set up into a cardboard box so that we won't make a mess for our experiments next week. We hope to find a better way to catch the sand, but our ideas all require us to attach material to our plate. We do not know if this will mess up our chances with gaining patterns and so we decided to keep our set up as simple as possible and slowly build from what works. We have obtained our amplifier and have tested it to make sure it was in good condition. We also decided that we will use corrugated plastic just for our prototype, but will eventually replace it with an aluminum plate. We need the exciter and plate to be placed over something and we chose to use a pvc pipe that is slightly smaller in radius than the exciter and 3-4 inches in length. We plan on connecting the pipe to the exciter with adhesives and the other end of the pipe to ply wood. We aren't sure how stable the plate will be in this format, hence why we decided to start with the corrugated plastic rather than jumping to the aluminum plate.


Our exciter and amplifier worked perfectly together! We were able to set up a prototype of our design using a corrugated plastic plate we bought and random PVC scraps available to salvage and use. We set up the plate and attached the exciter to it with duct tape, not the perfect design but we wanted to create a quick set up in order to see what our challenges will be when finalizing the design. Unfortunately, we weren't able to find a symmetrical design but this was because the plate wasn't leveling properly while attached to the exciter. Another thing to note was that at max amp volume, we were only able to get physical vibration under ~800Hz. We deduced that this is because of the way the corrugated plastic plate is formed and believe the aluminum plate will manage better results. We plan on extending our experimenting to a week in order to finalize on the design, use the aluminum plate, and make sure the plate is leveled properly. Here is a quick video of a trial at 440Hz:


For the Arduino part, we have connected a button to the breakboard which is ready for use. For the doing part, Mainly we use the syntax "tone", which generates a square wave of the specified frequency (and 50% duty cycle) on a pin. A duration can be specified, otherwise the wave continues until a call to "noTone()". The pin can be connected to a speaker/DAC to play tones. Our board can generates the frequency range from 31 Hz to 65535 Hz.