Digital Thermometer

/***********************************************************
 *  MATRIX ORBITAL - DISPLAY TEMPERATURE SAMPLE CODE
 *  December 16, 2002 
 *  This program demonstrates how to communicate with a DS1620 chip
 *  to check for the room temperature in degree Celsius.
 *  Once the program has the temperature, it proceeds to display it on a
 *  CD using large digits.
 *  The program iterates endlessly checking and displaying the
 *  temperature every minute.
 *  LIMITATIONS:
 *  1. This program assumes that the temperature will never be below 0
 *      or above 99 degrees Celsius.
 *  2. This program also assumes a minimum LCD size of 4 rows by 20
 *      columns.
 ***********************************************************/

// Stamp core basic classes
import stamp.core.*;
// This class encapsulates the basic capabilities of the Dallas DS1620 3-wire
// temperature sensor
import stamp.peripheral.sensor.temperature.DS1620;

public class DisplayTemp {

  // A virtual peripheral UART.
  // Each instance of this class provides asynchronous serial communication
  // ina single direction. For full-duplex communications create two Uart
  // objects, one for each direction.
  // Uart.dirTransmit -> Uart will be used to transmit data only.
  // CPU.pin0 -> Pin used to transmit data
  // Uart.dontInvert -> data is not inverted
  // Uart.speed19200 -> serial data transfer speed (baud rate)
  // Uart.stop1 -> Number of stop bits used is 1
  static Uart txUart = new Uart(Uart.dirTransmit, CPU.pin0, Uart.dontInvert,
                                           Uart.speed19200, Uart.stop1 );

  // main function drives the program
  public static void main() {

    // Creates DS1620 temperature sensor object
    // CPU.pin4: Data pin
    // CPU.pin5: Clock pin
    // CPU.pin6: RST
    DS1620 indoor = new DS1620(CPU.pin4,CPU.pin5,CPU.pin6);
    int iTemp = 0;   // Holds temperature in Celsious
    int iTenths = 0; // Most significant digit of temperature (Tenths)
    int iOnes = 0;   // Least significant digit of temperature (Ones)

    // General display settings
    // Clear screen
    txUart.sendByte(0xFE); // Command Prefix
    txUart.sendByte(0x58); // Clear command
    // Underline Off
    txUart.sendByte(0xFE); // Command Prefix
    txUart.sendByte(0x4B); // Underline off command
    // Blinking Off
    txUart.sendByte(0xFE); // Command Prefix
    txUart.sendByte(0x54); // Blinking off command

    // Display 'Degree Celsius' beside number of degrees
    // Position cursor
    txUart.sendByte(0xFE); // Command Prefix
    txUart.sendByte(0x47); // Move cursor command
    txUart.sendByte(0x09); // column position
    txUart.sendByte(0x02); // row position
    // Send text to the above cursor position
    txUart.sendString("Degrees");  //Sends the word "Degrees" to the LCD
    // Next Line - Move cursor to the next line
    txUart.sendByte(0xFE); // Command Prefix
    txUart.sendByte(0x47); // Move cursor command
    txUart.sendByte(0x09); // column position
    txUart.sendByte(0x03); // row position
    // Send text to the above position
    txUart.sendString("Celsius"); // Sends the word "Celsius" to the LCD
    // Large Digits On
    txUart.sendByte(0xFE); // Command Prefix
    txUart.sendByte(0x6E); // Large digits on command
    // Infinite Loop that checks current temperature and displays it
    while(true)
    {
      // Get Temperature in Celsius
      iTemp = indoor.getTempC();  // Requests temperature from DS1620
      // Get tenths - the most significant digit to display first
      iTenths = (int)iTemp / 10;
      // Get ones - the least significant digit to display second
      iOnes = iTemp - iTenths * 10;
      // Send temperature to lcd - first tenths then ones
      // Send tenths
      txUart.sendByte(0xFE); // Command Prefix
      txUart.sendByte(0x23); // Large digit command
      txUart.sendByte(0x01); // Column location - Large digits take-up 3 cols
      txUart.sendByte(iTenths); // Digit - Takes up columns 1, 2, and 3
      // Send ones - leave column 4 blank
      txUart.sendByte(0xFE); // Command Prefix
      txUart.sendByte(0x23); // Large digit command
      txUart.sendByte(0x05); // Column location - 1,2,3 taken-up by tenths
      txUart.sendByte(iOnes); // Digit - Takes up columns 5, 6, an 7
      // Pause for a minute - maximum delay is 32 seconds
      CPU.delay(32000); // Pauses for 32 seconds
      CPU.delay(32000); // Pauses for 32 seconds
    }
  }
} 

Example #2

You can redefine custom characters on the fly and even when they are displayed. If you have a custom character displays, you can change they way the all look by resending the information to it!

Stamp: Javelin Stamp
Communication Type: Serial
Display Used: Any Matrix Orbital display that supports serial communication such as the MOS or LK/VK/PK series

Displaying Animated Custom Characters:

We have two examples of code here, they both will do the exact same thing, just in two different ways.

EXAMPLE I

This example uses two custom characters and will display one and then the other to create motion.

public class CustomChar1
{
  static Uart txUart = new Uart(Uart.dirTransmit, CPU.pin0, Uart.dontInvert, Uart.speed19200, Uart.stop1 );

  public static void main()
  {
    txUart.sendByte(0xFE);
    txUart.sendByte('X');       //clear screen

    txUart.sendByte(0xFE);    //command prefix
    txUart.sendByte('N');     //custom character command
    txUart.sendByte(0x00);    //custom character value 0-7
    txUart.sendByte(14);      //8 bytes to create the custom character
    txUart.sendByte(14);
    txUart.sendByte(4);
    txUart.sendByte(31);
    txUart.sendByte(4);
    txUart.sendByte(4);
    txUart.sendByte(10);
    txUart.sendByte(17);

    txUart.sendByte(0xFE);    //command prefix
    txUart.sendByte('N');     //custom character command
    txUart.sendByte(0x01);    //custom character value 0-7
    txUart.sendByte(14);      //8 bytes to create the custom character
    txUart.sendByte(14);
    txUart.sendByte(21);
    txUart.sendByte(14);
    txUart.sendByte(4);
    txUart.sendByte(4);
    txUart.sendByte(10);
    txUart.sendByte(10);

    while (true)
    {
      txUart.sendByte(0xFE);    //command prefix
      txUart.sendByte('H');     //send cursor home
      txUart.sendByte(0x00);    //display custom character 0x00
      CPU.delay(5000);          //pause
      txUart.sendByte(0xFE);    //command prefix
      txUart.sendByte('H');     //send cursor home
      txUart.sendByte(0x01);    //display custom character 0x01
      CPU.delay(5000);          //pause
    }
   }

EXAMPLE II

This example uses only one custom character, but redefines the data of it every single time.

public class CustomChar2
{
  static Uart txUart = new Uart(Uart.dirTransmit, CPU.pin0, Uart.dontInvert, Uart.speed19200, Uart.stop1 );

  public static void main()
  {

    txUart.sendByte(0xFE);
    txUart.sendByte('X');       //clear screen
    txUart.sendByte(0x00);     //display custom character 0

    while (true)
    {
      CustomChar2.Char1();
      CPU.delay(5000);
      CustomChar2.Char2();
      CPU.delay(5000);
    }
   }

  public static void Char1()
    {
    txUart.sendByte(0xFE);    //command prefix
    txUart.sendByte('N');     //custom characer command
    txUart.sendByte(0x00);    //custom character value 0-7
    txUart.sendByte(14);      //8 bytes to create the custom caharacter
    txUart.sendByte(14);
    txUart.sendByte(4);
    txUart.sendByte(31);
    txUart.sendByte(4);
    txUart.sendByte(4);
    txUart.sendByte(10);
    txUart.sendByte(17);
    }

  public static void Char2()
    {
    txUart.sendByte(0xFE);    //command prefix
    txUart.sendByte('N');     //custom character command
    txUart.sendByte(0x00);    //custom character value 0-7
    txUart.sendByte(14);      //8 bytes to create the custom character
    txUart.sendByte(14);
    txUart.sendByte(21);
    txUart.sendByte(14);
    txUart.sendByte(4);
    txUart.sendByte(4);
    txUart.sendByte(10);
    txUart.sendByte(10);
    }
}

For technical discussions and questions, please visit our forums

Example#1

Large Digits

// Uart.dirTransmit -> Uart will be used to transmit data only.
// CPU.pin0 -> Pin used to transmit data
// Uart.dontInvert -> data is not inverted
// Uart.speed19200 -> serial data transfer speed (baud rate)
// Uart.stop1 -> Number of stop bits used is 1

static Uart txUart = new Uart(Uart.dirTransmit, CPU.pin0, Uart.dontInvert, Uart.speed19200, Uart.stop1 );


// Countdown from 9 to 0
    txUart.sendByte(0xFE);    // Command prefix
    txUart.sendByte(0x6E);    // Initialize large digits

    for(i = 9; i >= 0; i--)   // Iterate from 9 to 0
    {
      txUart.sendByte(0xFE);  // Command prefix
      txUart.sendByte(0x23);  // Place large digits command
      txUart.sendByte(19);    // Column where to start placing digit
      txUart.sendByte(i);     // Digit to display (From 9 to 0)
      CPU.delay(30000);       // Pause for 3 seconds to allow viewing
    }

In this code, the display will display 10 large digits, starting with 9 and going to 0. You can expand on this by creating 2+ more numbers at the same time. This code is usefull for the digital thermometer we will be building next.

For technical discussions and questions, please visit our forums

Sending commands to a display from a Javelin Stamp.

Sending text to a display from a Javelin Stamp.