• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Resource icon

Arduino Displaying Temperature via 74HC595's to 7-Seg's 2010-07-05

My original project is here

Code:
#include <DallasTemperature.h>

int bottomDataPin = 5; 
int bottomLatchPin = 6;
int bottomClockPin = 7;
int topLatchPin = 3;
int topClockPin = 4;
int topDataPin = 2;
int j = 1;
int toShift_Top = 0;
int toShift_Bottom = 0;
char m[4];
byte data;
byte dataArray[10];

DallasTemperature tempSensor0;
DallasTemperature tempSensor1;

void setup() {
  pinMode(topLatchPin, OUTPUT);
  pinMode(bottomLatchPin, OUTPUT);
  Serial.begin(9600);
  tempSensor0.begin(11);
  tempSensor1.begin(12);

  dataArray[0] = 0x3F; // 0
  dataArray[1] = 0x06; // 1
  dataArray[2] = 0x5B; // 2
  dataArray[3] = 0x4F; // 3
  dataArray[4] = 0x66; // 4
  dataArray[5] = 0x6D; // 5
  dataArray[6] = 0x7C; // 6
  dataArray[7] = 0x07; // 7
  dataArray[8] = 0x7F; // 8
  dataArray[9] = 0x67; // 9

  // clear both displays with 0's
  // top
  digitalWrite(topLatchPin, 0);
  shiftOut(topDataPin, topClockPin, dataArray[0]);
  shiftOut(topDataPin, topClockPin, dataArray[0]);
  shiftOut(topDataPin, topClockPin, dataArray[0]);
  shiftOut(topDataPin, topClockPin, dataArray[0]);
  digitalWrite(topLatchPin, 1);
  //bottom
  digitalWrite(bottomLatchPin, 0);
  shiftOut(bottomDataPin, bottomClockPin, dataArray[0]);
  shiftOut(bottomDataPin, bottomClockPin, dataArray[0]);
  shiftOut(bottomDataPin, bottomClockPin, dataArray[0]);
  shiftOut(bottomDataPin, bottomClockPin, dataArray[0]);
  digitalWrite(bottomLatchPin, 1);
}

void loop() 
{
  int k = 1000;
  toShift_Top = (tempSensor0.getTemperature() * 100);

  // the following code is by EmilyJane of arduino.cc forums
  int temp = toShift_Top;
  for (int i = 3; i >= 0; i--)
  {
    m[i] = temp / k;
    temp = temp - (m[i] * k);
    k = k / 10;
  }
  // end
  digitalWrite(topLatchPin, 0);
  shiftOut(topDataPin, topClockPin, dataArray[m[0]]);   
  shiftOut(topDataPin, topClockPin, dataArray[m[1]]);   
  shiftOut(topDataPin, topClockPin, dataArray[m[2]]);   
  shiftOut(topDataPin, topClockPin, dataArray[m[3]]); 
  digitalWrite(topLatchPin, 1);
  
  k = 1000;
  toShift_Bottom = (tempSensor1.getTemperature() * 100);
  // again, the following code is by EmilyJane of arduino.cc forums
  temp = toShift_Bottom;
  for (int i = 3; i >= 0; i--) 
  {
    m[i] = temp / k;
    temp = temp - (m[i] * k);
    k = k / 10;
  }
  // end
  digitalWrite(bottomLatchPin, 0);
  shiftOut(bottomDataPin, bottomClockPin, dataArray[m[0]]);   
  shiftOut(bottomDataPin, bottomClockPin, dataArray[m[1]]);   
  shiftOut(bottomDataPin, bottomClockPin, dataArray[m[2]]);   
  shiftOut(bottomDataPin, bottomClockPin, dataArray[m[3]]); 
  digitalWrite(bottomLatchPin, 1);
}

// the heart of the program
void shiftOut(int myDataPin, int myClockPin, byte myDataOut) 
{
  // This shifts 8 bits out MSB first, 
  //on the rising edge of the clock,
  //clock idles low

  //internal function setup
  int i=0;
  int pinState;
  pinMode(myClockPin, OUTPUT);
  pinMode(myDataPin, OUTPUT);

  //clear everything out just in case to
  //prepare shift register for bit shifting
  digitalWrite(myDataPin, 0);
  digitalWrite(myClockPin, 0);

  //for each bit in the byte myDataOut?
  //NOTICE THAT WE ARE COUNTING DOWN in our for loop
  //This means that %00000001 or "1" will go through such
  //that it will be pin Q0 that lights. 
  for (i=7; i>=0; i--)  {
    digitalWrite(myClockPin, 0);

    //if the value passed to myDataOut and a bitmask result 
    // true then... so if we are at i=6 and our value is
    // %11010100 it would the code compares it to %01000000 
    // and proceeds to set pinState to 1.
    if ( myDataOut & (1<<i) ) {
      pinState= 1;
    }
    else {	
      pinState= 0;
    }

    //Sets the pin to HIGH or LOW depending on pinState
    digitalWrite(myDataPin, pinState);
    //register shifts bits on upstroke of clock pin  
    digitalWrite(myClockPin, 1);
    //zero the data pin after shift to prevent bleed through
    digitalWrite(myDataPin, 0);
  }

  //stop shifting
  digitalWrite(myClockPin, 0);

}
Basically, I bought an Arduino from Creatron here in Toronto and decided to learn to code and play around, as they looked like a good way to get into uC's. I wanted to display the temperature from some free DS18S20 sensors I got onto some 7-seg's. However, I quickly realized it was going to kill me in the sheer amount of pins it would need.

After learning about shift registers a week or two in class I figured it would be the perfect test. And after lots of soldering and playing around, I designed this:





And it works great! Best of all, it worked on the first attempt. If you have any questions, comments, suggestions, etc, please feel free to leave them!
Author
ParkingLotLust
Views
169
First release
Last update
Rating
0.00 star(s) 0 ratings

EE World Online Articles

Loading
Top