Lab3

Assignment: Sensing: Potentiometers

Collaborators:

Description:

A project that uses the Arduino board and programming environment to demonstrate how to make three separate LEDs light up according to a programmable interval.

Components List:

x3 Light Emitting Diodes (LED)
x3 Resistor (220 Ohm)
Breadboard
Arduino board
Laptop running Arduino 11
Power came from computer via USB Cable
Two rubber bands (to secure boards together)
Wires
solder (to attach wires to the potentiometers)
X3 Potentiometers

Notes:

I used the three hands to control the pots.

Acknowledgments:

The potentiometers were tangled but working. I’d like to arrange them better next time.

Code used in this Assignment:

/*
* "Coffee-cup" Color Mixer:
* Code for mixing and reporting PWM-mediated color
* Assumes Arduino 0004 or higher, as it uses Serial.begin()-style communication
*
* Control 3 LEDs with 3 potentiometers
* If the LEDs are different colors, and are directed at diffusing surface (stuck in a
* a Ping-Pong ball, or placed in a paper coffee cup with a cut-out bottom and
* a white plastic lid), the colors will mix together.
*
* When you mix a color you like, stop adjusting the pots.
* The mix values that create that color will be reported via serial out.
*
* Standard colors for light mixing are Red, Green, and Blue, though you can mix
* with any three colors; Red + Blue + White would let you mix shades of red,
* blue, and purple (though no yellow, orange, green, or blue-green.)
*
* Put 220 Ohm resistors in line with pots, to prevent circuit from
* grounding out when the pots are at zero
*/

// Analog pin settings
int aIn = 4; // Potentiometers connected to analog pins 0, 1, and 2
int bIn = 3; // (Connect power to 5V and ground to analog ground)
int cIn = 2;
// Digital pin settings
int aOut = 9; // LEDs connected to digital pins 9, 10 and 11
int bOut = 10; // (Connect cathodes to digital ground)
int cOut = 11;
// Values
int aVal = 0; // Variables to store the input from the potentiometers
int bVal = 0; int cVal = 0;
// Variables for comparing values between loops
int i = 0; // Loop counter
int wait = (1000); // Delay between most recent pot adjustment and output

int checkSum = 0; // Aggregate pot values
int prevCheckSum = 0;
int sens = 3; // Sensitivity theshold, to prevent small changes in
// pot values from triggering false reporting
// FLAGS
int PRINT = 1; // Set to 1 to output values
int DEBUG = 1; // Set to 1 to turn on debugging output

void setup()
{
pinMode(aOut, OUTPUT); // sets the digital pins as output
pinMode(bOut, OUTPUT); pinMode(cOut, OUTPUT);
Serial.begin(9600); // Open serial communication for reporting
}

void loop()
{
i += 1; // Count loop

aVal = analogRead(aIn) / 4; // read input pins, convert to 0-255 scale
bVal = analogRead(bIn) / 4;
cVal = analogRead(cIn) / 4;
analogWrite(aOut, aVal); // Send new values to LEDs
analogWrite(bOut, bVal);
analogWrite(cOut, cVal);

if (i % wait == 0) // If enough time has passed...
{ checkSum = aVal+bVal+cVal; // ...add up the 3 values.
if ( abs(checkSum - prevCheckSum) > sens ) // If old and new values differ
// above sensitivity threshold
{
if (PRINT) // ...and if the PRINT flag is set...
{
Serial.print("A: "); // ...then print the values.
Serial.print(aVal); Serial.print("\t");
Serial.print("B: "); Serial.print(bVal);
Serial.print("\t");
Serial.print("C: "); Serial.println(cVal);
PRINT = 0;
}
} else
{
PRINT = 1; // Re-set the flag }
prevCheckSum = checkSum; // Update the values

if (DEBUG) // If we want debugging output as well...
{
Serial.print(checkSum);
Serial.print("<=>");
Serial.print(prevCheckSum);
Serial.print("\tPrint: ");
Serial.println(PRINT);
}
}
}

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