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TouchScreen Interfacing v.90
Paris Miles-Brenden
Copyright 2013

Process:
May 3rd: Began buying parts.
May 11th: Messed up first SMT to DIP.
May 14th: Drilled holes in PCB to mount PCB in enclosure.
May 15th: Successfully mounted SMT to DIP adapter and tested.
May 17th: Purchased mounting hardware for Arduino and tested SMT to DIP functionality.
May 18th: Drilled and cut holes for USB connectors, Powers In, Switches, and Touchscreen Out.
May 19th: Tested output of TTL levels of Arduino to CMOS levels after transistors.
May 20th: Installed DDS-60, buffer amp, and voltage dividers and tested.
May 21st: Connected op-amps and fixed up SMT to DIP adapter, tested with Arduino.
May 22nd: Generated first tangible image.
Ready to program!

Interface Testing
* 1.)  Test AD8302 before signals:  Apply +5VDC to pin 4, GND to pin 1 or 7, and measure VREF at pin 11.  Should measure 1.8VDC.

	a.) I could not have persistently touched it like I did for more than 3-5 seconds after each soldering attempt without a burn, had it fried.  From this I can reason that I did not overheat it (fries at 80 degrees celsius).
	b.) From the VREF at ~1.8VDC the interior circuitry is working (I did not ESD shock it).
	c.) And from my tests of all pins, etc, I determined there are no shorts, AND all pins are connected properly.

Results:
VREF: 1.836 VDC

* 2.)  Test digital out of Arduino with in-line transistors:  Toggle digital pins on/off, and with 10K resistor in-line with voltage switched (+5VDC).  Measure high/low at emitter.

Results:
Pin 1-3:
Set HIGH in Arduino: ~3.850 VDC
Set LOW in Arduino: ~0.610 VDC

Connect to pins 1,2,3 of DDS-60.
Pin 1 = Load,  Pin 2 = Clock,  Pin 3 = Data

* 3.)  Test DDS-60 before coupling to output amplifier:  Apply +12VDC and GND.  Send digital signal in of 14000 Hz, and tune to +/-1VAC.  Measure output with a multimeter.

Results:
	Measured .5 Vrms @ 14000 Hz at maximum voltage.  Measured 7.6VDC at input to board with electrolytic capacitor between VIN and GND, and 3.9 Ohm resistor in line with VIN.  Removed 3.9 Ohm resistor to remedy voltage and measured 11.74 VDC at VIN.  Measured .72 Vrms @ 45000 Hz.  Figured out this is an artifact of the impedance of the multimeter, and the high pass filter of the DDS-60, which should smooth out to 4 Vp-p @ 2 MHz.

* 4.)  Test buffer amp (BW pin!) and potentiometer voltage divider:  Tune for +4VDC output on +5VDC, and -2VDC output on -5VDC.

Results:
	At first the connections to GND and +12VDC of the power regulator were not connected, resulting in readings of zero voltage relative to ground.  Then these were connected, and the power out at the midpoint of the voltage divider could be tuned within .005 volts of the desired values.

* 5.)  Connect to Arduino analog ADC IN's, and program to receive one set of 20 magnitude and phase measurements.  Generate image plot with Mathematica for simple test object.