Getting Started • Check out: http://arduino.cc/en/Guide/HomePage 1. Download & install the Arduino environment (IDE) (not needed in lab) 2. Connect the board to your computer via the USB cable 3. If needed, install the drivers (not needed in lab) 4. Launch the Arduino IDE 5. Select your board 6. Select your serial port 7. Open the blink example 8. Upload the program
Arduino Digital I/0 www.mikroe.com/chapters/view/1 pinMode(pin, mode) Sets pin to either INPUT or OUTPUT digitalRead(pin) Reads HIGH or LOW from a pin digitalWrite(pin, value) Writes HIGH or LOW to a pin Electronic stuff Output pins can provide 40 mA of current Writing HIGH to an input pin installs a 20KΩ pullup
Arduino Analog Input Image credit: Tod Kurt • Resolution: the number of different voltage levels (i.e., states) used to discretize an input signal • Resolution values range from 256 states (8 bits) to 4,294,967,296 states (32 bits) • The Arduino uses 1024 states (10 bits) • Smallest measurable voltage change is 5V/1024 or 4.8 mV • Maximum sample rate is 10,000 times a second
Topic 3: Analog Output • Can a digital devise produce analog output? Image from Theory and Practice of Tangible User Interfaces at UC Berkley • Analog output can be simulated using pulse width modulation (PWM)
Pulse Width Modulation • Can’t use digital pins to directly supply say 2.5V, but can pulse the output on and off really fast to produce the same effect • The on-off pulsing happens so quickly, the connected output device “sees” the result as a reduction in the voltage Image from Theory and Practice of Tangible User Interfaces at UC Berkley
PMW Pins • Command: analogWrite(pin,value) • value is duty cycle: between 0 and 255 • Examples: analogWrite(9, 128) for a 50% duty cycle analogWrite(11, 64) for a 25% duty cycle Image from Theory and Practice of Tangible User Interfaces at UC Berkley
In-class Exercise 2: Analog IO Part 2: Add an LED • Add a 330 ohm resistor and an LED to pin 9 • Using the analogWrite() command, set the intensity of the LED as a function of the value of prReading
Serial Communication • Compiling turns your program into binary data (ones and zeros) • Uploading sends the bits through USB cable to the Arduino • The two LEDs near the USB connector blink when data is transmitted • RX blinks when the Arduino is receiving data • TX blinks when the Arduino is transmitting data todbot.com/blog/bionicarduino
Serial-to-USB chip---what does it do? The LilyPad and Fio Arduino require an external USB to TTY connector, such as an FTDI “cable”. In the Arduino Leonardo a single microcontroller runs the Arduino programs and handles the USB connection. Image from Theory and Practice of Tangible User Interfaces at UC Berkley
In-class Exercise 3: Serial Communication Modify your program from in-class exercise 2-part 2 to control the intensity of the LED attached to pin 9 based on keyboard input. Use the Serial.parseInt() method to read numeric keyboard input as an integer. An input of 9 should produce full intensity and an input of 0 should turn the LED off.
