1. DESIGN REVIEW: THE LIGHT LISTENER
Justin Manuel Rivera Bergonio
12 December 2013
PHYS 475 / Professor Varner

2. Motivation/Fun Facts Human eye can detect: Human ear can discern
Light changes of 0.02 s
f < 50Hz
Human ear can discern
f between 20Hz to 20,000 Hz
Objective(s):
Make audible these fast pulses
Make audible other “invisible” light sources

3. Light Listener Circuit
+9V
Detector/receiver( ?)
IR Phototransistor
Signal Amplifier
741 Op Amp
Audio Amplifier
386 Audio Op Amp
Fixed Gain: 20
Speaker
8Ω Mini Speaker
1μF
100kΩ
0.1μF
100kΩ
741 8Ω
100μF
0.1μF
10kΩ
386
From: Forest M. Mims III Enegineers Mini Notebook

4. Timeline Progress: Further (Possible) Implementations Gather materials
Construct light listener circuit
Tested light listener circuit
Further (Possible) Implementations
On/off switch for power supply (by 12/13/2013)
Counter with Display (by 12/16/2013)
Stop/Start/Reset
Used in tandem with a stopwatch  get frequencies
Output sound to earphones?