Intro to the Arduino.ppt

1、Intro to the Arduino,Topics: The ArduinoDigital IOAnalog IO Serial Communication,Topic 1: Meet Arduino Uno,Getting Started,Check out: http:/arduino.cc/en/Guide/HomePage Download & install the Arduino environment (IDE) (not needed in lab) Connect the board to your computer via the USB cable If needed

2、, install the drivers (not needed in lab) Launch the Arduino IDE Select your board Select your serial port Open the blink example Upload the program,Arduino IDE,See: http:/arduino.cc/en/Guide/Environment for more information,Select Serial Port and Board, from Theory and Practice of Tangible User Int

3、erfaces at UC Berkley,Topic 2: Digital Input/Output,Digital IO is binary valuedits either on or off, 1 or 0 Internally, all microprocessors are digital, why?,1,0,Arduino Digital I/0,pinMode(pin, mode) Sets pin to either INPUT or OUTPUTdigitalRead(pin) Reads HIGH or LOW from a pindigitalWrite(pin, va

4、lue) Writes HIGH or LOW to a pinElectronic stuff Output pins can provide 40 mA of current Writing HIGH to an input pin installs a 20K pullup, First Program,IO Pins,Image from Theory and Practice of Tangible User Interfaces at UC Berkley,In-class Exercise 1: Digital IO,Use a push-button to turn ON/Of

5、f LED,Topic 3: Analog Input,Think about music stored on a CD-an analog signal captured on digital media Sample rate Word length,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 state

6、s (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,Arduino Analog Input,Image credit: Tod Kurt,How does ADC work?,How does ADC work Excel Demonstration,Can a digital devise produce analog output?,Top

7、ic 3: Analog Output,Analog output can be simulated using pulse width modulation (PWM),Image from Theory and Practice of Tangible User Interfaces at UC Berkley,Pulse Width Modulation,Cant use digital pins to directly supply say 2.5V, but can pulse the output on and off really fast to produce the same

8、 effectThe 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,PWM Duty Cycle,Fixed cycle length; constant number of cycles/sec,Image credit: Tod Kurt,output voltage =

9、(on_time / cycle_time) * 5V,PMW Pins,Command: analogWrite(pin,value)value is duty cycle: between 0 and 255Examples: analogWrite(9, 128) for a 50% duty cycleanalogWrite(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,

10、A light theremin,Part 1:,In-class Exercise 2: Analog IO,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,Part 2: Add an LED,Topic 4: Serial Communication,Image from http:/ Communication,Compiling turns yo

11、ur 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, the Serial Monitor and Upload the Pr

12、ogram,Some Commands,Serial.begin() - e.g., Serial.begin(9600) Serial.print() or Serial.println()- e.g., Serial.print(value) Serial.read() Serial.available() Serial.write() Serial.parseInt(),Example Program,Serial-to-USB chip-what does it do?,Image from Theory and Practice of Tangible User Interfaces

13、 at UC Berkley,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.,Two different communication protocols,Serial (TTL):,Image from http:/www.fiz- Proto

14、col,Much more complicated,Image from http:/en.wikipedia.org/wiki/USB,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.,