MAS.S60
Problem Set 7 - Final Project
Due Wednesday 10.17.12


This is an addendum to the final project, as outlined in PS#6.

To build the playback amplifier, you will need to connect up to the tapehead on the
 cassette mechanism you received in class.  A drawing of this mechanism showing the
 tapehead location, and which pins to solder to, is given here:

http://web.media.mit.edu/~geppetto/vids/tapehead.jpg

The leads you will connect to are the ones on the lefthand side of the tapehead, when
 viewed with the motor on the bottom.  This is where the signal from the tape can be
 read.  Unfortunately, the tapehead signal is very small, usually on the order of a few
 millivolts.  To amplify this so it can be heard, you will need to build an opamp circuit
 with a gain of approximately 1,000.  This will then go to a power amplifier stage so it
 can drive a speaker.  Be sure to bias your amplifiers to mid-rail, or you won't hear a
 clean signal.

On the tape is recorded a 1kHz tone.  By varying the tape playback speed, the frequency
 of this tone is varied.  Have this playback speed controlled by your arduino and light
 sensor.  If you are working with a group, the light sensor should send its data over the
 IR link to the cassette mechanism.  If you are working alone, you do not need to have
 an IR link (But you still need to show the IR link working for PS#6).