every year, electrical engineering students at ucla pick an ieee project to fill their time and bolster their extracurriculars/jeopardize their gpa. due to my tendency to do the latter, the student project initiative project seemed to be the most obvious choice: "free" money to create projects that may or may not work, but that they are glad to invest in. my self-driven endeavor of choice was to create musical intruments using random electronic parts, in particular (but not limited to) a barcode scanner and a fan. as with many of my decisions, this one was done in a spontaneous moment of motivation and hunger, and like many such decisions the results are equal parts impressive (depending on how easily impressed you are) and disappointing (depending on how strict you are). perhaps i was holding off making this page for a long time exactly because of how disappointed i was in this project, but like my voltage multiplier i believe it deserves a spot in josh's engineering portfolio for friends and family.
the one working thing in this project is the barcode scanner synth, which only marginally works. it is a digital barcode scanner that employs a 2d laser reading unit to collect information from assorted black lines. it is essentially reading out a square wave, with a positive pulse when it reads a black line and no pulse when it reads the white (though i read somewhere that it actually reads the other way around). to simulate this, i drew black lines onto a sticky note and stuck it to the ieee lab's back bench, where it resided until the end of the year. i then used oscilloscopes to probe the reader to see which pins were for ground and for the signal. after finding these respective signals, i soldered wired onto the pins and soldered the other end to an audio jack so that it would be played from an amplifier. the setup looked like this:
there was one main problem regarding the line scanner, however, and that was that it was digital and the output actually included the timing protocol into it as shown here:
as you could see, there is a periodic rectangular spike. this spike proved to be a big problem since it propagated into the output. the other fluctuations in the signal come from the actual barcode signal, however that signal is overpowered by the spikes, which is very obvious in the actual sound coming out of the amplifier. the result of this experiment ended up being that the scanning distance would end up controlling overtones instead of the actual output frequency. my friend pepper, however, was able to get their hands on some analog barcode scanners from the chinese secondhand market, which did not have the digital communications protocol and could create cohesive frequency changes like it was intended to. if i had any videos or photos, i would post them here but currently i do not have any so this article may be a work in progress.