FAST-PULSED LIGHT TO AUDIO CONVERTING DEVICE Justin R. Bergonio PHYS 475 / Prof. Gary Varner 17 December 2013

Motivation  The human eye can:  Discern pulses of light as short as 0.02s  Pulse frequency: 50Hz  The human ear can detect:  Sound f: 20Hz to 20kHz  Goal:  Convert fast light pulses into sound  Convert “invisble” light into sound form 2 Courtesy: hebeiltd.com Courtesy: dhgate.com

The Plan 3 Detect signal Differentiate signal Amplify signal Create controlled signal (vary f) Transmit signal Output signal to speaker

Circuit: Square Wave Generator  Astable operation  Output jumps back and forth  555 internal:  3 x 5k Ω resistors  2 comparators  RS Flip Flop  Frequency:  f range:  14 – 140 Hz (100k Ω pot)  960 – 1440 Hz (1k Ω pot) 4 R1R1 R2R2 C1C1

Circuit: Light Listener  IR Phototransistor  Sensitive: 850nm  Also detects visible  741 Op Amp  V cc = 5 – 15V  Differentiator config.  386 Audio Op Amp  Fixed gain: 20dB  Drives 8 Ω speaker  8 Ω Speaker  f range: 300 – 8000Hz 5 Forrest M Mims III, Enegineer’s Mini Notebook: Vol. II

Tests 6

Tests: Varying Frequencies Out Op Amp Out Audio Op Amp Out 25Hz

Tests: Varying Frequencies Out Op Amp Out Audio Op Amp Out 70Hz

Tests: Other Sources 9 Op Amp Out Op Amp Out Audio Op Amp Out Audio Op Amp Out Florescent LightsIR Remote Control

Random Applications  Tone generator  Annoy the crap out of your siblings/parents/anyo ne  Become the life of the party 10 Courtesy: monsterworking.comCourtesy: paulstallard.com Courtesy: picgifs.com

Conclusion “WE’VE ONLY JUST BEGUN.” - The Carpenters  Goals met:  Made audible fast light pulses  Made audible “invisible” light  The future:  Continue electronics (as a hobby)  Adventures: Learn to short wave radio Build a “radio telescope” & listen to Jupiter Other interesting things 11

12 Thank you and don’t get eaten by a T-Rex.

References  Mims, Forrest M. Engineer ʹ s Mini Notebook: Science and Communication Circuits & Projects. Vol. 2. Niles: Master, Print.  Scherz, Paul, and Simon Monk. Practical Electronics for Inventors. New York, NY: McGraw-Hill, Print.  Trillesto. "Flashing L.E.D. Using 555 Timer." Instructables.com. Autodesk Inc., n.d. Web. 17 Dec

Tests: Random Stuff 14 Op Amp Out Op Amp Out Audio Op Amp Out Audio Op Amp Out Florescent Lights Circuit OFFCircuit ON

Tests: Random Stuff 15 Op Amp Out Op Amp Out Audio Op Amp Out Audio Op Amp Out Florescent Lights f ZOOM INf ZOOM OUT