Ubiquitous Computing Practice (Photo Resistor) Youn-Hee Han, In-Seok Kang {yhhan, Laboratory of Intelligent Networks Advanced Technology Research Center Korea University of Technology

/ 24 Introduction PhotoResistor LED 밝기 조절 Processing 를 이용한 Graph 2 Contents

/ 24 PhotoResistor ( Cadmium sulfide or Light dependent resistor ) 빛의 세기에 따라 저항 값이 변하는 센서이다 3 Introduction

/ 244 Introduction

/ 245 Introduction

/ 246 Introduction

/ 247 Introduction

/ 24 PHOTO RESISTOR 8

/ 249 Photo resistor

/ 2410 schematic

/ 2411 Result

/ 24 Functions analogRead(pin) – analog pin 에서 int (0~1023) 반환 analogWrite(pin, val) – val(0~255) 값 출력 Serial begin(baud) – bits per second  ex)9600, print(val) – 시리얼 통신 이용 val 출력  Serial.print(78) gives "78" print(val, format) – val 을 원하는 format 에 맞춰 출력  Serial.print(78, BIN) gives " " 12 Reference

/ 24 Math map(value, fromLow, fromHigh, toLow, toHigh)  Value 현재 값의 범위 fromLow ~ fromHigh  변경하고 싶은 값의 범위 toLow, toHigh  ex) int val = analogRead(0); val = map(val, 0, 1023, 0, 255); constrain(inputVal, lowRange, highRange)  inputVal 값이 lowRange ~ highRange 사이의 값이면 inputVal 반환  inputVal 값이 lowRange 값 보다 작으면 lowRange 값 반환  inputVal 값이 highRange 값 보다 크면 highRange 값 반환 13 Reference

/ 2414 센서의 analog 값 출력 Sketch int photocellPin = 0; int photocellReading; void setup(void) { Serial.begin(9600); // bit per second. } void loop(void) { photocellReading = analogRead(photocellPin); Serial.print("Analog reading = "); Serial.println(photocellReading); delay(1000); }

/ 24 LED 밝기 조절 15

/ 2416 LED 밝기 조절

/ 2417 schematic

/ 2418 LED 밝기 조절 Sketch int lightPin = 0; int ledPin = 11; void setup() { pinMode(ledPin, OUTPUT); } void loop() { int lightLevel = analogRead(lightPin); lightLevel = 1023 – lightLevel; lightLevel = map(lightLevel, 0, 1023, 0, 255); lightLevel = constrain(lightLevel, 0, 255); analogWrite(ledPin, lightLevel); }

/ 24 PROCESSING 를 이용한 GRAPH Processing 을 이용하여 Graph 를 출력하기 19

/ 2420 Arduino board

/ 2421 Arduino - Sketch int photoPin = 0; void setup() { Serial.begin(9600); } void loop() { Serial.println(analogRead(photoPin)); delay(100); }

/ 2422 Processing - Sketch import processing.serial.*; Serial myPort; // The serial port int xPos = 1; // horizontal position of the graph void setup () { size(400, 300); println(Serial.list()); myPort = new Serial(this, Serial.list()[1], 9600); myPort.bufferUntil('\n'); background(0); } void draw () { }

/ 2423 Processing - Sketch void serialEvent (Serial myPort) { String inString = myPort.readStringUntil('\n'); if (inString != null) { inString = trim(inString); float inByte = float(inString); inByte = map(inByte, 0, 1023, 0, height); stroke(127,34,255); line(xPos, height, xPos, height - inByte); if (xPos >= width) { xPos = 0; background(0); } else { xPos++; }

/ 2424 Result