Digital Ruler With IR Distance And Electron

// This #include statement was automatically added by the Particle IDE.
#include "Adafruit_SSD1306/Adafruit_SSD1306.h"



#include"application.h"
#include"math.h"
#define IR_PORT  A0



// use hardware SPI,so only need to config DataCommand, ChipSelect, Reset Pins
//#define OLED_MOSI A5  //DI
//#define OLED0_MISO A4
//#define OLED_SCK  A3  //DO
#define OLED_CS A2
#define OLED_DC A1
#define OLED_RESET D0

Adafruit_SSD1306 oled(OLED_DC, OLED_RESET, OLED_CS);


SYSTEM_MODE(SEMI_AUTOMATIC);


unsigned char distance =10;     
unsigned char max_distance = 0;
unsigned char min_distance = 100;


unsigned char algorithm_sensor()
{
    unsigned int sensorValue = 0;
    unsigned int value = 0;
    float analog=0.0;
    float temp=0.0;
    sensorValue = analogRead(IR_PORT); 
    analog = (sensorValue/4095.0)*3.3;
    
    //get this algorithm from sparkfun web,but seems not very good, 
    //a better method should be premeasure the adc value at each distance and then use the EXCEL to find out a pow algorithm 
    //with good parameter.
    temp = 306.439 + analog*( -512.611 + analog*(382.268 +analog*(-129.893 + analog*16.2537) ) );   
    distance = int(round(temp));
    Serial.print(distance);
    Serial.print("\r\n");
}


void setup() {
    Serial.begin(9600);
    oled.begin(SSD1306_SWITCHCAPVCC); 
    
    Serial.print("This is a demo project for distance sensor\r\n");
    pinMode(IR_PORT,INPUT);
    delay(2000);
  // miniature bitmap display
    oled.display();
    oled.clearDisplay();
    oled.setTextSize(1);
    oled.setTextColor(WHITE);
    
    oled.setCursor(0,0);
    
    oled.println("    TUTORIAL 1");     //the first line
    oled.println("");       //do nothing here,just to leave one space line
    oled.print("DISTANCE:");            //the second line
    oled.print(distance, DEC);
    oled.println(" CM");
    oled.println("");       //do nothing here,just to leave one space line

    oled.print("MAX DISTANCE:");      //the third line
    oled.print(distance, DEC);
    oled.println(" CM");    
    oled.println("");       //do nothing here,just to leave one space line
     
    oled.print("MIM DISTANCE:");      //the fourth line
    oled.print(distance, DEC);
    oled.print(" CM"); 
    oled.display();
}


void loop() {

    delay(500);                 //update the distance value every 500ms
    algorithm_sensor();

    if(distance>max_distance)       //get the maximum distance
        max_distance = distance;
    if(distance<min_distance)       //get the minimum distance
        min_distance = distance;
        
    oled.clearDisplay();
    oled.setCursor(0,0);        //need to set the original cursor for every loop;
    
    oled.println("    TUTORIAL 1");     //the first line
    oled.println("");       //do nothing here,just to leave one space line
    oled.print("DISTANCE:");            //the second line
    oled.print(distance, DEC);
    oled.println(" CM");
    oled.println("");       //do nothing here,just to leave one space line

    oled.print("MAX DISTANCE:");      //the third line
    oled.print(max_distance, DEC);
    oled.println(" CM");    
    oled.println("");       //do nothing here,just to leave one space line
     
    oled.print("MIM DISTANCE:");      //the fourth line
    oled.print(min_distance, DEC);
    oled.print(" CM"); 
    
    if(distance>127)
        distance = 127;
    oled.fillRect(0,60,distance,3,WHITE);       //drawing the distance table.
    oled.display();
    distance++;
    if(distance==100)
        distance = 0;
}