LAB 3: MICROCONTROLLERS

Goals
- Basic microcontroller understanding
- Basic knowledge of the Arduino board in relation to other platforms

Small Computers vs. Big Computers
- Speed, memory, cost

Microcontrollers <http://en.wikipedia.org/wiki/Microcontroller>
- Different from a microprocessor
- Memory
- Microcontroller boards in education (past and present)?
- Often programmed in Assembly, C, BASIC
- Arduino vs. Wiring

Arduino
- Board variations
- What's on the board
 . Power select, regulator, options
 . Analog In
 . Digital Out (be careful with pin 0,1)
 . PWM Out (explain PWM)
 . USB chip
 . Oscillator
- Programming
 . C
 . Differences between Processing and Wiring language
   . loop()
   . variable declaration
   . pin definition
   . etc.


Exercises
- Build the "knight_rider_3" example (included with the Arduino software). Modify the code to alter the blinking pattern based on another idea. (Reminder, you need to use a resistor with each LEDs, see Igoe p. 99)

Reading to complete for next class
- Physical Computing (pp. 249 - 283)


//

Example 1: Analog IN

1. Range of potentiometer with Multimeter.
2. Find corresponding resistor (same value of max resistance) or use...
  http://people.clarkson.edu/~svoboda/eta/designLab/VoltageDividerDesign.html
3. Build the circuit on breadboard (Igoe, p. 105)
4. Code:

int resistorPin = 0;    // Select the input pin for the potentiometer
int val;  // Store value here

void setup() {
 Serial.begin(9600); // Open the serial port at 9600 bps:
}

void loop() {
 val = analogRead(resistorPin);  // Read the value from the sensor
 Serial.println(val);  // Print as an ASCII-encoded decimal
 delay(10);
}


5. Watch the values, record min and max

//

Example 2: Analog OUT

1. Solder 8 Ohm speaker
2. Build circuit
3. Code:

int outPin = 10;

void setup() { }

void loop() {
 analogWrite(outPin, 60);
}


//

Example 3: Analog IN > OUT

1. Build circuit
3. Code:

int outPin = 10;  // Speaker connected to digital pin 10
int analogPin = 0;  // Potentiometer connected to analog pin 0
int val = 0;  // Variable to store the read value

void setup() { }

void loop()
{
 val = analogRead(analogPin);  // Read the input pin
 // analogRead values go from 0 to 1023, analogWrite values from 0 to 255
 analogWrite(outPin, val / 4);
}