Category Archives: arduino

0.96" 80 x 160 Full Color IPS LCD Module from PMD Way with free delivery worldwide

Tutorial – Using the 0.96″ 80 x 160 Full Color IPS LCD Module with Arduino

The purpose of this guide is to get your 0.96″ color LCD display successfully operating with your Arduino, so you can move forward and experiment and explore further types of operation with the display. This includes installing the Arduino library, making a succesful board connection and running a demonstration sketch.

Although you can use the display with an Arduino Uno or other boad with an ATmega328-series microcontroller – this isn’t recommended for especially large projects. The library eats up a fair amount of flash memory – around 60% in most cases.

So if you’re running larger projects we recommend using an Arduino Mega or Due-compatible board due to the increased amount of flash memory in their host microcontrollers.

Installing the Arduino library

So let’s get started. We’ll first install the Arduino library then move on to hardware connection and then operating the display.

(As the display uses the ST7735S controller IC, you may be tempted to use the default TFT library included with the Arduino IDE – however it isn’t that reliable. Instead, please follow the instructions below). 

First – download the special Arduino library for your display and save it into your Downloads or a temp folder.

Next – open the Arduino IDE and select the Sketch > Include Library > Add .ZIP library option as shown below:

libraryinstall

A dialog box will open – navigate to and select the zip file you downloaded earlier. After a moment or two the IDE will then install the library.

Please check that the library has been installed – to do this, select the Sketch > Include Library option in the IDE and scroll down the long menu until you see “ER-TFTM0.96-1” as shown below:

libraryinstalled

Once that has been successful, you can wire up your display.

Connecting the display to your Arduino

The display uses the SPI data bus for communication, and is a 3.3V board. You can use it with an Arduino or other 5V board as the logic is tolerant of higher voltages.

Arduino to Display

GND ----- GND (GND)
3.3V ---- Vcc (3.3V power supply)
D13 ----- SCL (SPI bus clock)
D11 ----- SDA (SPI bus data out from Arduino)
D10 ----- CS (SPI bus "Chip Select")
D9 ------ DC (Data instruction select pin)
D8 ------ RES (reset input)

If your Arduino has different pinouts than the Uno, locate the SPI pins for your board and modify as appropriate.

Demonstration sketch

Open a new sketch in the IDE, then copy and paste the following sketch into the IDE:

// https://pmdway.com/products/0-96-80-x-160-full-color-lcd-module
#include <UTFT.h>

// Declare which fonts we will be using
extern uint8_t SmallFont[];

// Initialize display
// Library only supports software SPI at this time
//NOTE: support  DUE , MEGA , UNO 
//SDI=11  SCL=13  /CS =10  /RST=8  D/C=9
UTFT myGLCD(ST7735S_4L_80160,11,13,10,8,9);    //LCD:  4Line  serial interface      SDI  SCL  /CS  /RST  D/C    NOTE:Only support  DUE   MEGA  UNO

// Declare which fonts we will be using
extern uint8_t BigFont[];

int color = 0;
word colorlist[] = {VGA_WHITE, VGA_BLACK, VGA_RED, VGA_BLUE, VGA_GREEN, VGA_FUCHSIA, VGA_YELLOW, VGA_AQUA};
int  bsize = 4;

void drawColorMarkerAndBrushSize(int col)
{
  myGLCD.setColor(VGA_BLACK);
  myGLCD.fillRect(25, 0, 31, 239);
  myGLCD.fillRect(myGLCD.getDisplayXSize()-31, 161, myGLCD.getDisplayXSize()-1, 191);
  myGLCD.setColor(VGA_WHITE);
  myGLCD.drawPixel(25, (col*30)+15);
  for (int i=1; i<7; i++)
    myGLCD.drawLine(25+i, ((col*30)+15)-i, 25+i, ((col*30)+15)+i);
  
  if (color==1)
    myGLCD.setColor(VGA_WHITE);
  else
    myGLCD.setColor(colorlist[col]);
  if (bsize==1)
    myGLCD.drawPixel(myGLCD.getDisplayXSize()-15, 177);
  else
    myGLCD.fillCircle(myGLCD.getDisplayXSize()-15, 177, bsize);
    
  myGLCD.setColor(colorlist[col]);
}
void setup()
{
  randomSeed(analogRead(0));
  
// Setup the LCD
  myGLCD.InitLCD();
  myGLCD.setFont(SmallFont);
}

void loop()
{
  int buf[158];
  int x, x2;
  int y, y2;
  int r;

// Clear the screen and draw the frame
  myGLCD.clrScr();

  myGLCD.setColor(255, 0, 0);
  myGLCD.fillRect(0, 0, 159, 13);
  myGLCD.setColor(64, 64, 64);
  myGLCD.fillRect(0, 114, 159, 127);
  myGLCD.setColor(255, 255, 255);
  myGLCD.setBackColor(255, 0, 0);
  myGLCD.print("pmdway.com.", CENTER, 1);
  myGLCD.setBackColor(64, 64, 64);
  myGLCD.setColor(255,255,0);
  myGLCD.print("pmdway.com", LEFT, 114);


  myGLCD.setColor(0, 0, 255);
  myGLCD.drawRect(0, 13, 159, 113);

// Draw crosshairs
  myGLCD.setColor(0, 0, 255);
  myGLCD.setBackColor(0, 0, 0);
  myGLCD.drawLine(79, 14, 79, 113);
  myGLCD.drawLine(1, 63, 158, 63);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);
 
  for (int i=9; i<150; i+=10)
    myGLCD.drawLine(i, 61, i, 65);
  for (int i=19; i<110; i+=10)
    myGLCD.drawLine(77, i, 81, i);
    

// Draw sin-, cos- and tan-lines  
  myGLCD.setColor(0,255,255);
  myGLCD.print("Sin", 5, 15);
  for (int i=1; i<158; i++)
  {
    myGLCD.drawPixel(i,63+(sin(((i*2.27)*3.14)/180)*40));
  }
  
  myGLCD.setColor(255,0,0);
  myGLCD.print("Cos", 5, 27);
  for (int i=1; i<158; i++)
  {
    myGLCD.drawPixel(i,63+(cos(((i*2.27)*3.14)/180)*40));
  }

  myGLCD.setColor(255,255,0);
  myGLCD.print("Tan", 5, 39);
  for (int i=1; i<158; i++)
  {
    myGLCD.drawPixel(i,63+(tan(((i*2.27)*3.14)/180)));
  }

  delay(2000);

  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  myGLCD.setColor(0, 0, 255);
  myGLCD.setBackColor(0, 0, 0);
  myGLCD.drawLine(79, 14, 79, 113);
  myGLCD.drawLine(1, 63, 158, 63);

 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);  

// Draw a moving sinewave
  x=1;
  for (int i=1; i<(158*20); i++) 
  {
    x++;
    if (x==159)
      x=1;
    if (i>159)
    {
      if ((x==79)||(buf[x-1]==63))
        myGLCD.setColor(0,0,255);
      else
        myGLCD.setColor(0,0,0);
      myGLCD.drawPixel(x,buf[x-1]);
    }
    myGLCD.setColor(0,255,255);
    y=63+(sin(((i*2.5)*3.14)/180)*(40-(i / 100)));
    myGLCD.drawPixel(x,y);
    buf[x-1]=y;
  }

  delay(2000);
 
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);  

// Draw some filled rectangles
  for (int i=1; i<6; i++)
  {
    switch (i)
    {
      case 1:
        myGLCD.setColor(255,0,255);
        break;
      case 2:
        myGLCD.setColor(255,0,0);
        break;
      case 3:
        myGLCD.setColor(0,255,0);
        break;
      case 4:
        myGLCD.setColor(0,0,255);
        break;
      case 5:
        myGLCD.setColor(255,255,0);
        break;
    }
    myGLCD.fillRect(39+(i*10), 23+(i*10), 59+(i*10), 43+(i*10));
  }

  delay(2000);
  
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);   

// Draw some filled, rounded rectangles
  for (int i=1; i<6; i++)
  {
    switch (i)
    {
      case 1:
        myGLCD.setColor(255,0,255);
        break;
      case 2:
        myGLCD.setColor(255,0,0);
        break;
      case 3:
        myGLCD.setColor(0,255,0);
        break;
      case 4:
        myGLCD.setColor(0,0,255);
        break;
      case 5:
        myGLCD.setColor(255,255,0);
        break;
    }
    myGLCD.fillRoundRect(99-(i*10), 23+(i*10), 119-(i*10), 43+(i*10));
  }

  delay(2000);
  
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);

 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);  
// Draw some filled circles
  for (int i=1; i<6; i++)
  {
    switch (i)
    {
      case 1:
        myGLCD.setColor(255,0,255);
        break;
      case 2:
        myGLCD.setColor(255,0,0);
        break;
      case 3:
        myGLCD.setColor(0,255,0);
        break;
      case 4:
        myGLCD.setColor(0,0,255);
        break;
      case 5:
        myGLCD.setColor(255,255,0);
        break;
    }
    myGLCD.fillCircle(49+(i*10),33+(i*10), 15);
  }

  delay(2000);
    
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);    

// Draw some lines in a pattern
  myGLCD.setColor (255,0,0);
  for (int i=14; i<113; i+=5)
  {
    myGLCD.drawLine(1, i, (i*1.44)-10, 112);
  }
  myGLCD.setColor (255,0,0);
  for (int i=112; i>15; i-=5)
  {
    myGLCD.drawLine(158, i, (i*1.44)-12, 14);
  }
  myGLCD.setColor (0,255,255);
  for (int i=112; i>15; i-=5)
  {
    myGLCD.drawLine(1, i, 172-(i*1.44), 14);
  }
  myGLCD.setColor (0,255,255);
  for (int i=15; i<112; i+=5)
  {
    myGLCD.drawLine(158, i, 171-(i*1.44), 112);
  }

  delay(2000);
  
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);    

// Draw some random circles
  for (int i=0; i<100; i++)
  {
    myGLCD.setColor(random(255), random(255), random(255));
    x=22+random(116);
    y=35+random(57);
    r=random(20);
    myGLCD.drawCircle(x, y, r);
  }

  delay(2000);
  
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);    
  

// Draw some random rectangles
  for (int i=0; i<100; i++)
  {
    myGLCD.setColor(random(255), random(255), random(255));
    x=2+random(156);
    y=16+random(95);
    x2=2+random(156);
    y2=16+random(95);
    myGLCD.drawRect(x, y, x2, y2);
  }

  delay(2000);
  
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);    

// Draw some random rounded rectangles
  for (int i=0; i<100; i++)
  {
    myGLCD.setColor(random(255), random(255), random(255));
    x=2+random(156);
    y=16+random(95);
    x2=2+random(156);
    y2=16+random(95);
    myGLCD.drawRoundRect(x, y, x2, y2);
  }

  delay(2000);
  
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);  
 
  for (int i=0; i<100; i++)
  {
    myGLCD.setColor(random(255), random(255), random(255));
    x=2+random(156);
    y=16+random(95);
    x2=2+random(156);
    y2=16+random(95);
    myGLCD.drawLine(x, y, x2, y2);
  }

  delay(2000);
  
  myGLCD.setColor(0,0,0);
  myGLCD.fillRect(1,14,158,113);
  
 myGLCD.setColor(0, 0, 255);
 myGLCD.drawLine(0, 79, 159, 79);  
 
  for (int i=0; i<5000; i++)
  {
    myGLCD.setColor(random(255), random(255), random(255));
    myGLCD.drawPixel(2+random(156), 16+random(95));
  }

  delay(2000);

  myGLCD.fillScr(0, 0, 255);
  myGLCD.setColor(255, 0, 0);
  myGLCD.fillRoundRect(10, 17, 149, 72);
  
  myGLCD.setColor(255, 255, 255);
  myGLCD.setBackColor(255, 0, 0);
  myGLCD.print("That's it!", CENTER, 20);
  myGLCD.print("Restarting in a", CENTER, 45);
  myGLCD.print("few seconds...", CENTER, 57);
  
  myGLCD.setColor(0, 255, 0);
  myGLCD.setBackColor(0, 0, 255);
  myGLCD.print("Runtime: (msecs)", CENTER, 103);
  myGLCD.printNumI(millis(), CENTER, 115);

  delay (5000);   
}

 

Once you’re confident with the physical connection, upload the sketch. It should result with output as shown in the video below:

Now that you have succesfully run the demonstration sketch – where to from here?

The library used is based on the uTFT library by Henning Karlsen. You can find all the drawing and other commands in the user manual – so download the pdf and enjoy creating interesting displays.

This post brought to you by pmdway.com – everything for makers and electronics enthusiasts, with free delivery worldwide.

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0.96" 128 x 64 Graphic OLED Displays - I2C or SPI - Various Colors from PMD Way with free delivery worldwide

Tutorial – Using the 0.96″ 128 x 64 Graphic I2C OLED Displays with Arduino

The purpose of this guide is to have an SSD1306-based OLED display successfully operating with your Arduino, so you can move forward and experiment and explore further types of operation with the display.

This includes installing the Arduino library, making a succesful board connection and running a demonstration sketch. So let’s get started!

Connecting the display to your Arduino

The display uses the I2C data bus for communication, and is a 5V and 3.3V-tolerant board.

Arduino Uno to Display

GND ---- GND (GND)
5V/3.3V- Vcc (power supply, can be 3.3V or 5V)
A5 ----- SCL (I2C bus clock)
A4 ----- SDA (I2C bus data)

I2C pinouts vary for other boards. Arduino Leonard uses D2/D3 for SDA and SCL or the separate pins to the left of D13. Arduino Mega uses D20/D21 for SDA and SCL. If you can’t find your I2C pins on other boards, ask your display supplier.

Installing the Arduino library

To install the library – simply open the Arduino IDE and select Manage Libraries… from the Tools menu. Enter “u8g2” in the search box, and after a moment it should appear in the results as shown in the image below. Click on the library then click “Install”:

install-library-u8g2

After a moment the library will be installed and you can close that box.

Now it’s time to check everything necessary is working. Open a new sketch in the IDE, then copy and paste the following sketch into the IDE:

// Display > https://pmdway.com/products/0-96-128-64-graphic-oled-displays-i2c-or-spi-various-colors

#include <Arduino.h>
#include <U8x8lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

  U8X8_SSD1306_128X64_NONAME_HW_I2C u8x8(/* reset=*/ U8X8_PIN_NONE);   

/*
  This example will probably not work with the SSD1606, because of the
  internal buffer swapping
*/

void setup(void)
{
  /* U8g2 Project: KS0108 Test Board */
  //pinMode(16, OUTPUT);
  //digitalWrite(16, 0);  

  /* U8g2 Project: Pax Instruments Shield: Enable Backlight */
  //pinMode(6, OUTPUT);
  //digitalWrite(6, 0); 

  u8x8.begin();
  //u8x8.setFlipMode(1);
}

void pre(void)
{
  u8x8.setFont(u8x8_font_amstrad_cpc_extended_f);    
  u8x8.clear();

  u8x8.inverse();
  u8x8.print(" U8x8 Library ");
  u8x8.setFont(u8x8_font_chroma48medium8_r);  
  u8x8.noInverse();
  u8x8.setCursor(0,1);
}

void draw_bar(uint8_t c, uint8_t is_inverse)
{ 
  uint8_t r;
  u8x8.setInverseFont(is_inverse);
  for( r = 0; r < u8x8.getRows(); r++ )
  {
    u8x8.setCursor(c, r);
    u8x8.print(" ");
  }
}

void draw_ascii_row(uint8_t r, int start)
{
  int a;
  uint8_t c;
  for( c = 0; c < u8x8.getCols(); c++ )
  {
    u8x8.setCursor(c,r);
    a = start + c;
    if ( a <= 255 )
      u8x8.write(a);
  }
}

void loop(void)
{
  int i;
  uint8_t c, r, d;
  pre();
  u8x8.print("github.com/");
  u8x8.setCursor(0,2);
  u8x8.print("olikraus/u8g2");
  delay(2000);
  u8x8.setCursor(0,3);
  u8x8.print("Tile size:");
  u8x8.print((int)u8x8.getCols());
  u8x8.print("x");
  u8x8.print((int)u8x8.getRows());
  
  delay(2000);
   
  pre();
  for( i = 19; i > 0; i-- )
  {
    u8x8.setCursor(3,2);
    u8x8.print(i);
    u8x8.print("  ");
    delay(150);
  }
  
  draw_bar(0, 1);
  for( c = 1; c < u8x8.getCols(); c++ )
  {
    draw_bar(c, 1);
    draw_bar(c-1, 0);
    delay(50);
  }
  draw_bar(u8x8.getCols()-1, 0);

  pre();
  u8x8.setFont(u8x8_font_amstrad_cpc_extended_f); 
  for( d = 0; d < 8; d ++ )
  {
    for( r = 1; r < u8x8.getRows(); r++ )
    {
      draw_ascii_row(r, (r-1+d)*u8x8.getCols() + 32);
    }
    delay(400);
  }

  draw_bar(u8x8.getCols()-1, 1);
  for( c = u8x8.getCols()-1; c > 0; c--)
  {
    draw_bar(c-1, 1);
    draw_bar(c, 0);
    delay(50);
  }
  draw_bar(0, 0);

  pre();
  u8x8.drawString(0, 2, "Small");
  u8x8.draw2x2String(0, 5, "Scale Up");
  delay(3000);

  pre();
  u8x8.drawString(0, 2, "Small");
  u8x8.setFont(u8x8_font_px437wyse700b_2x2_r);
  u8x8.drawString(0, 5, "2x2 Font");
  delay(3000);

  pre();
  u8x8.drawString(0, 1, "3x6 Font");
  u8x8.setFont(u8x8_font_inb33_3x6_n);
  for(i = 0; i < 100; i++ )
  {
    u8x8.setCursor(0, 2);
    u8x8.print(i);      // Arduino Print function
    delay(10);
  }
  for(i = 0; i < 100; i++ )
  {
    u8x8.drawString(0, 2, u8x8_u16toa(i, 5)); // U8g2 Build-In functions
    delay(10);    
  }

  pre();
  u8x8.drawString(0, 2, "Weather");
  u8x8.setFont(u8x8_font_open_iconic_weather_4x4);
  for(c = 0; c < 6; c++ )
  {
    u8x8.drawGlyph(0, 4, '@'+c);
    delay(300);
  }
  

  pre();
  u8x8.print("print \\n\n");
  delay(500);
  u8x8.println("println");
  delay(500);
  u8x8.println("done");
  delay(1500);

  pre();
  u8x8.fillDisplay();
  for( r = 0; r < u8x8.getRows(); r++ )
  {
    u8x8.clearLine(r);
    delay(100);
  }
  delay(1000);
}

Your display should go through the demonstration of various things as shown in the video below:

If the display did not work – you may need to manually set the I2C bus address. To do this, wire up your OLED then run this sketch (open the serial monitor for results). It’s an I2C scanner tool that will return the I2C bus display. 

Then use the following line in void setup():

u8x8.setI2CAddress(address)

Replace u8x8 with your display reference, and address with the I2C bus address (for example. 0x17).

Moving on…

By now you have an idea of what is possible with these great-value displays.

Now your display is connected and working, it’s time to delve deeper into the library and the various modes of operations. There are three, and they are described in the library documentation – click here to review them

Whenever you use one of the three modes mentioned above, you need to use one of the following constructor lines:

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); // full buffer mode

U8X8_SSD1306_128X64_NONAME_HW_I2C u8x8(/* reset=*/ U8X8_PIN_NONE); // 8x8 character mode

U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); // page buffer mode

Match the mode you wish to use with one of the constructors above. For example, in the demonstration sketch you ran earlier, we used the 8×8 character mode constructor in line 14.

Where to from here?

Now it’s time for you to explore the library reference guide which explains all the various functions available to create text and graphics on the display, as well as the fonts and so on. These can all be found on the right-hand side of the driver wiki page.

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LED Real Time Clock Temperature Sensor Shield for Arduino

Tutorial – LED Real Time Clock Temperature Sensor Shield for Arduino

In this tutorial we look at how to use the neat LED Real Time Clock Temperature Sensor Shield for Arduino from PMD Way. That’s a bit of a mouthful, however the shield does offer the following:

  • four digit, seven-segment LED display
  • DS1307 real-time clock IC
  • three buttons
  • four LEDs
  • a active buzzer
  • a light-dependent resistor (LDR)
  • and a thermistor for measuring ambient temperature

led-real-time-clock-temperature-sensor-shield-arduino-pmdway-1

The shield also arrives fully-assembled , so you can just plug it into your Arduino Uno or compatible board. Neat, beginners will love that. So let’s get started, by showing how each function can be used – then some example projects. In no particular order…

The buzzer

A high-pitched active buzzer is connected to digital pin D6 – which can be turned on and off with a simple digitalWrite() function. So let’s do that now, for example:

void setup() {
  // buzzer on digital pin 6
  pinMode(6, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(6, HIGH);   // turn the buzzer on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(6, LOW);    // turn the buzzer off by making the voltage LOW
  delay(1000);                       // wait for a second
}

If there is a white sticker over your buzzer, remove it before uploading the sketch. Now for a quick video demonstration. Turn down your volume before playback.

The LEDs

Our shield has four LEDs, as shown below:

led-real-time-clock-temperature-sensor-shield-arduino-pmdway-LEDs

They’re labelled D1 through to D4, with D1 on the right-hand side. They are wired to digital outputs D2, D3, D4 and D5 respectively. Again, they can be used with digitalWrite() – so let’s do that now with a quick demonstration of some blinky goodness. Our sketch turns the LEDs on and off in sequential order. You can change the delay by altering the variable x:

void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(2, OUTPUT); // LED 1
  pinMode(3, OUTPUT); // LED 2
  pinMode(4, OUTPUT); // LED 3
  pinMode(5, OUTPUT); // LED 4
}

int x = 200;

void loop() {
  digitalWrite(2, HIGH);    // turn on LED1
  delay(x);
  digitalWrite(2, LOW);    // turn off LED1. Process repeats for the other three LEDs
  digitalWrite(3, HIGH);
  delay(x);
  digitalWrite(3, LOW);
  digitalWrite(4, HIGH);
  delay(x);
  digitalWrite(4, LOW);
  digitalWrite(5, HIGH);
  delay(x);
  digitalWrite(5, LOW);
}

And in action:

The Buttons

It is now time to pay attention to the three large buttons on the bottom-left of the shield. They look imposing however are just normal buttons, and from right-to-left are connected to digital pins D9, D10 and D11:

LED Real Time Clock Temperature Sensor Shield for Arduino from PMD Way

They are, however, wired without external pull-up or pull-down resistors so when initialising them in your Arduino sketch you need to activate the digital input’s internal pull-up resistor inside the microcontroller using:

pinMode(pin, INPUT_PULLUP);

Due to this, buttons are by default HIGH when not pressed. So when you press a button, they return LOW. The following sketch demonstrates the use of the buttons by lighting LEDs when pressed:

void setup() {
  // initalise digital pins for LEDs as outputs
  pinMode(2, OUTPUT); // LED 1
  pinMode(3, OUTPUT); // LED 2
  pinMode(4, OUTPUT); // LED 3

  // initalise digital pins for buttons as inputs
  // and initialise internal pullups
  pinMode(9, INPUT_PULLUP); // button K1
  pinMode(10, INPUT_PULLUP); // button K2
  pinMode(11, INPUT_PULLUP); // button K3
}

void loop()
{
  if (digitalRead(9) == LOW)
  {
    digitalWrite(2, HIGH);
    delay(10);
    digitalWrite(2, LOW);
  }

  if (digitalRead(10) == LOW)
  {
    digitalWrite(3, HIGH);
    delay(10);
    digitalWrite(3, LOW);
  }

  if (digitalRead(11) == LOW)
  {
    digitalWrite(4, HIGH);
    delay(10);
    digitalWrite(4, LOW);
  }
}

You can see these in action via the following video:

The Numerical LED Display

Our shield has a nice red four-digit, seven-segment LED clock display. We call it a clock display as there are colon LEDs between the second and third digit, just as a digital clock would usually have:

LED Real Time Clock Temperature Sensor Shield for Arduino from PMD Way with free delivery worldwide

The display is controlled by a special IC, the Titan Micro TM1636:

TM1636 Numerical LED Display Driver IC from PMD Way with free delivery worldwide

The TM1636 itself is an interesting part, so we’ll explain that in a separate tutorial in the near future. For now, back to the shield.

To control the LED display we need to install an Arduino library. In fact the shield needs four, so you can install them all at once now. Download the .zip file from here. Then expand that into your local download directory – it contains four library folders. You can then install them one at a time using the Arduino IDE’s Sketch > Include library > Add .zip library… command:

LED Real Time Clock Temperature Sensor Shield for Arduino from PMD Way with free delivery worldwide

The supplied library offers five functions used to control the display.

.num(x);

…this displays a positive integer (whole number) between 0 and 9999.

.display(p,d);

… this shows a digit d in location p (locations from left to right are 3, 2, 1, 0)

.time(h,m)

… this is used to display time data (hours, minutes) easily. h is hours, m is minutes

.pointOn();
.pointOff();

… these turn the colon on … and off. And finally:

.clear();

… which clears the display to all off. At the start of the sketch, we need to use the library and initiate the instance of the display by inserting the following lines:

#include <TTSDisplay.h>
TTSDisplay rtcshield;

Don’t panic – the following sketch demonstrates the five functions described above:

#include <TTSDisplay.h>
TTSDisplay rtcshield;

int a = 0;
int b = 0;

void setup() {}

void loop()
{
  // display some numbers
  for (a = 4921; a < 5101; a++)
  {
    rtcshield.num(a);
    delay(10);
  }

  // clear display
  rtcshield.clear();

  // display individual digits
  for (a = 3; a >= 0; --a)
  {
    rtcshield.display(a, a);
    delay(1000);
    rtcshield.clear();
  }
  for (a = 3; a >= 0; --a)
  {
    rtcshield.display(a, a);
    delay(1000);
    rtcshield.clear();
  }

  // turn the colon and off
  for (a = 0; a < 5; a++)
  {
    rtcshield.pointOn();
    delay(500);
    rtcshield.pointOff();
    delay(500);
  }

  // demo the time display function
  rtcshield.pointOn();
  rtcshield.time(11, 57);
  delay(1000);
  rtcshield.time(11, 58);
  delay(1000);
  rtcshield.time(11, 59);
  delay(1000);
  rtcshield.time(12, 00);
  delay(1000);
}

And you can see it in action through the video below:

The LDR (Light Dependent Resistor)

LDRs are useful for giving basic light level measurements, and our shield has one connected to analog input pin A1. It’s the two-legged item with the squiggle on top as shown below:

led-real-time-clock-temperature-sensor-shield-arduino-pmdway-LDR

The resistance of LDRs change with light levels – the greater the light, the less the resistance. Thus by measuring the voltage of a current through the LDR with an analog input pin – you can get a numerical value proportional to the ambient light level. And that’s just what the following sketch does:

#include <TTSDisplay.h>
TTSDisplay rtcshield;

int a = 0;

void setup() {}
void loop()
{
  // read value of analog input
  a = analogRead(A1);
  // show value on display
  rtcshield.num(a);
  delay(100);
}

The Thermistor

A thermistor is a resistor whose resistance is relative to the ambient temperature. As the temperature increases, their resistance decreases. It’s the black part to the left of the LDR in the image below:

led-real-time-clock-temperature-sensor-shield-arduino-pmdway-LDR

We can use this relationship between temperature and resistance to determine the ambient temperature. To keep things simple we won’t go into the theory – instead, just show you how to get a reading.

The thermistor circuit on our shield has the output connected to analog input zero, and we can use the library installed earlier to take care of the mathematics. Which just leaves us with the functions.

At the start of the sketch, we need to use the library and initiate the instance of the thermistor by inserting the following lines:

#include <TTSTemp.h>
TTSTemp temp;

… then use the following which returns a positive integer containing the temperature (so no freezing cold environments):

.get();

For our example, we’ll get the temperature and show it on the numerical display:

#include <TTSDisplay.h>
#include <TTSTemp.h>

TTSTemp temp;
TTSDisplay rtcshield;

int a = 0;

void setup() {}

void loop() {

  a = temp.get();
  rtcshield.num(a);
  delay(500);
}

And our thermometer in action. No video this time… a nice 24 degrees C in the office:

led-real-time-clock-temperature-sensor-shield-arduino-pmdway-thermometer

The Real-Time Clock 

Our shield is fitted with a DS1307 real-time clock IC circuit and backup battery holder. If you insert a CR1220 battery, the RTC will remember the settings even if you remove the shield from the Arduino or if there’s a power blackout, board reset etc:

LED Real Time Clock Temperature Sensor Shield for Arduino from PMD Way with free delivery worldwide

The DS1307 is incredibly popular and used in many projects and found on many inexpensive breakout boards. We have a separate tutorial on how to use the DS1307, so instead of repeating ourselves – please visit our specific DS1307 Arduino tutorial, then return when finished.

Where to from here? 

We can image there are many practical uses for this shield, which will not only improve your Arduino coding skills but also have some useful applications. An example is given below, that you can use for learning or fun.

Temperature Alarm

This projects turns the shield into a temperature monitor – you can select a lower and upper temperature, and if the temperature goes outside that range the buzzer can sound until you press it.

Here’s the sketch:

#include <TTSDisplay.h>
#include <TTSTemp.h>

TTSTemp temp;
TTSDisplay rtcshield;

boolean alarmOnOff = false;
int highTemp = 40;
int lowTemp = 10;
int currentTemp;

void LEDsoff()
{
  // function to turn all alarm high/low LEDs off
  digitalWrite(2, LOW);
  digitalWrite(4, LOW);
}

void setup() {
  // initalise digital pins for LEDs and buzzer as outputs
  pinMode(2, OUTPUT); // LED 1
  pinMode(3, OUTPUT); // LED 2
  pinMode(4, OUTPUT); // LED 3
  pinMode(5, OUTPUT); // LED 4
  pinMode(6, OUTPUT); // buzzer

  // initalise digital pins for buttons as inputs
  // and initialise internal pullups
  pinMode(9, INPUT_PULLUP); // button K1
  pinMode(10, INPUT_PULLUP); // button K2
  pinMode(11, INPUT_PULLUP); // button K3
}

void loop()
{
  // get current temperature
  currentTemp = temp.get();

  // if current temperature is within set limts
  // show temperature on display

  if (currentTemp >= lowTemp || currentTemp <= highTemp)
    // if ambient temperature is less than high boundary
    // OR if ambient temperature is grater than low boundary
    // all is well
  {
    LEDsoff(); // turn off LEDs
    rtcshield.num(currentTemp);
  }

  // if current temperature is above set high bounday, show red LED and
  // show temperature on display
  // turn on buzzer if alarm is set to on (button K3)

  if (currentTemp > highTemp)
  {
    LEDsoff(); // turn off LEDs
    digitalWrite(4, HIGH); // turn on red LED
    rtcshield.num(currentTemp);
    if (alarmOnOff == true) {
      digitalWrite(6, HIGH); // buzzer on }
    }
  }

  // if current temperature is below set lower boundary, show blue LED and
  // show temperature on display
  // turn on buzzer if alarm is set to on (button K3)

  if (currentTemp < lowTemp)
  {
    LEDsoff(); // turn off LEDs
    digitalWrite(2, HIGH); // turn on blue LED
    rtcshield.num(currentTemp);
    if (alarmOnOff == true)
    {
      digitalWrite(6, HIGH); // buzzer on }
    }
  }
  // --------turn alarm on or off-----------------------------------------------------
  if (digitalRead(11) == LOW) // turn alarm on or off
  {
    alarmOnOff = !alarmOnOff;
    if (alarmOnOff == 0) {
      digitalWrite(6, LOW); // turn off buzzer
      digitalWrite(5, LOW); // turn off alarm on LED
    }
    // if alarm is set to on, turn LED on to indicate this
    if (alarmOnOff == 1)
    {
      digitalWrite(5, HIGH);
    }
    delay(300); // software debounce
  }
  // --------set low temperature------------------------------------------------------
  if (digitalRead(10) == LOW) // set low temperature. If temp falls below this value, activate alarm
  {
    // clear display and turn on blue LED to indicate user is setting lower boundary
    rtcshield.clear();
    digitalWrite(2, HIGH); // turn on blue LED
    rtcshield.num(lowTemp);

    // user can press buttons K2 and K1 to decrease/increase lower boundary.
    // once user presses button K3, lower boundary is locked in and unit goes
    // back to normal state

    while (digitalRead(11) != LOW)
      // repeat the following code until the user presses button K3
    {
      if (digitalRead(10) == LOW) // if button K2 pressed
      {
        --lowTemp; // subtract one from lower boundary
        // display new value. If this falls below zero, won't display. You can add checks for this yourself :)
        rtcshield.num(lowTemp);
      }
      if (digitalRead(9) == LOW) // if button K3 pressed
      {
        lowTemp++; // add one to lower boundary
        // display new value. If this exceeds 9999, won't display. You can add checks for this yourself :)
        rtcshield.num(lowTemp);
      }
      delay(300); // for switch debounce
    }
    digitalWrite(2, LOW); // turn off blue LED
  }
  // --------set high temperature-----------------------------------------------------
  if (digitalRead(9) == LOW) // set high temperature. If temp exceeds this value, activate alarm
  {

    // clear display and turn on red LED to indicate user is setting lower boundary
    rtcshield.clear();
    digitalWrite(4, HIGH); // turn on red LED
    rtcshield.num(highTemp);

    // user can press buttons K2 and K1 to decrease/increase upper boundary.
    // once user presses button K3, upper boundary is locked in and unit goes
    // back to normal state

    while (digitalRead(11) != LOW)
      // repeat the following code until the user presses button K3
    {
      if (digitalRead(10) == LOW) // if button K2 pressed
      {
        --highTemp; // subtract one from upper boundary
        // display new value. If this falls below zero, won't display. You can add checks for this yourself :)
        rtcshield.num(highTemp);
      }
      if (digitalRead(9) == LOW) // if button K3 pressed
      {
        highTemp++; // add one to upper boundary
        // display new value. If this exceeds 9999, won't display. You can add checks for this yourself :)
        rtcshield.num(highTemp);
      }
      delay(300); // for switch debounce
    }
    digitalWrite(4, LOW); // turn off red LED
  }
}

Operating instructions:

  • To set lower temperature, – press button K2. Blue LED turns on. Use buttons K2 and K1 to select temperature, then press K3 to lock it in. Blue LED turns off.
  • To set upper temperature – press button K1. Red LED turns on. Use buttons K2 and K1 to select temperature, then press K3 to lock it in. Red LED turns off.
  • If temperature drops below lower or exceeds upper temperature, the blue or red LED will come on.
  • You can have the buzzer sound when the alarm activates – to do this, press K3. When the buzzer mode is on, LED D4 will be on. You can turn buzzer off after it activates by pressing K3.
  • Display will show ambient temperature during normal operation.

You can see this in action via the video below:

Conclusion

This is a fun and useful shield – especially for beginners. It offers a lot of fun and options without any difficult coding or soldering – it’s easy to find success with the shield and increase your motivation to learn more and make more.

You can be serious with a clock, or annoy people with the buzzer. And at the time of writing you can have one for US$14.95, delivered. So go forth and create something.

A little research has shown that this shield was based from a product by Seeed, who discontinued it from sale. I’d like to thank them for the library.

This post brought to you by pmdway.com – everything for makers and electronics enthusiasts, with free delivery worldwide.

To keep up to date with new posts at tronixstuff.com, please subscribe to the mailing list in the box on the right, or follow us on twitter @tronixstuff.

Tutorial – Arduino and Four Digit Seven Segment Display Module

This is a quick start guide for the Four Digit Seven Segment Display Module and Enclosure from PMD Way. This module offers a neat and bright display which is ideal for numeric or hexadecimal data. It can display the digits 0 to 9 including the decimal point, and the letters A to F. You can also control each segment individually if desired. 

Each module contains four 74HC595 shift registers – once of each controls a digit. If you carefully remove the back panel from the enclosure, you can see the pin connections:

four-digit-seven-segment-display-with-enclosure-from-pmdway

If you’re only using one display, use the group of pins at the centre-bottom of the board. From left to right the connections are:

  1. Data out (ignore for single display use)
  2. VCC – connect to a 3.3V or 5V supply
  3. GND – connect to your GND line
  4. SDI – data in – connect to the data out pin on your Arduino/other board
  5. LCK – latch – connect to the output pin on your Arduino or other board that will control the latch
  6. CLK – clock – connect to the output pin on your Arduino or other board that will control the clock signal

For the purposes of our Arduino tutorial, connect VCC to the 5V pin, GND to GND, SDI to D11, LCK to D13 and CLK to D12. 

If you are connecting more than one module, use the pins on the left- and right-hand side of the module. Start with the connections from your Arduino (etc) to the right-hand side, as this is where the DIN (data in) pin is located.

Then connect the pins on the left-hand side of the module to the right-hand side of the new module – and so forth. SDO (data out) will connect to the SDI (data in) – with the other pins being identical for connection. 

The module schematic is shown below:

four-digit-seven-segment-display-with-enclosure-from-pmdway

Arduino Example Sketch

Once you have made the connections to your Arduino as outlined above, upload the following sketch:

// Demonstration Arduino sketch for four digit, seven segment display with enclosure
// https://pmdway.com/collections/7-segment-numeric-leds/products/four-digit-seven-segment-display-module-and-enclosure
int latchPin = 13; // connect to LCK pin intclockPin = 12; // connect to CLK pin intdataPin = 11; // connect to SDI pin int LED_SEG_TAB[]={ 0xfc,0x60,0xda,0xf2,0x66,0xb6,0xbe,0xe0,0xfe,0xf6,0x01,0xee,0x3e,0x1a,0x7a,0x9e,0x8e,0x01,0x00}; //0 1 2 3 4 5 6 7 8 9 dp . a b c d e f off void setup() { //set pins to output so you can control the shift register pinMode(latchPin, OUTPUT); pinMode(clockPin, OUTPUT); pinMode(dataPin, OUTPUT); } void displayNumber(int value, boolean leadingZero) // break down "value" into digits and store in a,b,c,d { int a,b,c,d; a = value / 1000; value = value % 1000; b = value / 100; value = value % 100; c = value / 10; value = value % 10; d = value; if (leadingZero==false) // removing leading zeros { if (a==0 && b>0) { a = 18; } if (a==0 && b==0 && c>0) { a = 18; b = 18; } if (a==0 && b==0 && c==0) { a = 18; b = 18; c = 18; } if (a==0 && b==0 && c==0 && d==0) { a = 18; b = 18; c = 18; d = 18; } } digitalWrite(latchPin, LOW); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[d]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[c]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[b]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[a]); digitalWrite(latchPin, HIGH); } void allOff() // turns off all segments { digitalWrite(latchPin, LOW); shiftOut(dataPin, clockPin, LSBFIRST, 0); shiftOut(dataPin, clockPin, LSBFIRST, 0); shiftOut(dataPin, clockPin, LSBFIRST, 0); shiftOut(dataPin, clockPin, LSBFIRST, 0); digitalWrite(latchPin, HIGH); } void loop() { for (int z=900; z<=1100; z++) { displayNumber(z, false); delay(10); } delay(1000); for (int z=120; z>=0; --z) { displayNumber(z, true); delay(10); } delay(1000); digitalWrite(latchPin, LOW); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[14]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[13]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[12]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[11]); digitalWrite(latchPin, HIGH); delay(1000); digitalWrite(latchPin, LOW); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[16]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[15]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[14]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[13]); digitalWrite(latchPin, HIGH); delay(1000); digitalWrite(latchPin, LOW); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[0]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[1]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[2]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[3]+1); digitalWrite(latchPin, HIGH); delay(1000); digitalWrite(latchPin, LOW); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[7]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[6]+1); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[5]); shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[4]); digitalWrite(latchPin, HIGH); delay(1000); }

After a moment you should see the display spring into action in the same way as in the demonstration video:

How does it work? 

First we define which digital output pins are used for latch, clock and data on lines four to six. On line eight we have created an array which contains values that are sent to the shift registers in the module to display the possible digits and letters. For example, the first – 0xfc – will activate the segments to display a zero, 0x7a for the letter C, and so on. 

From line 20 we’ve created a custom function that is used to send a whole number between zero and 9999 to the display. To do so, simply use:

void displayNumber(value, true/false);

where value is the number to display (or variable containing the number) – and the second parameter of true or false. This controls whether you have a leading zero displayed – true for yes, false for no. 

For example, to display “0123” you would use:

displayNumber(123, true);

… which results with:

four-digit-seven-segment-display-with-enclosure-from-pmdway-0123

or to display “500” you would use:

displayNumber(500, false);

… which results with:

four-digit-seven-segment-display-with-enclosure-from-pmdway-500

To turn off all the digits, you need to send zeros to every bit in the shift register, and this is accomplished with the function in the sketch called 

allOff();

What about the decimal point? 

To turn on the decimal point for a particular digit, add 1 to the value being sent to a particular digit. Using the code from the demonstration sketch to display 87.65 you would use:

 digitalWrite(latchPin, LOW);

 shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[5]);

 shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[6]);

 shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[7]+1); // added one for decimal point

 shiftOut(dataPin, clockPin, LSBFIRST, LED_SEG_TAB[8]);

 digitalWrite(latchPin, HIGH);

… which results with:

four-digit-seven-segment-display-with-enclosure-from-pmdway-87p65

In-depth explanation of how the module is controlled

As shown in the schematic above, each digit is controlled by a 74HC595 shift register. Each shift register has eight digital outputs, each of which control an individual segment of each digit. So by sending four bytes of data (one byte = eight bits) you can control each segment of the display. 

Each digit’s segments are mapped as follows:

7segmentdisplaymap

And the outputs from each shift register match the order of segments from left to right. So outputs 0~7 match A~G then decimal point. 

For example, to create the number seven with a decimal point, you need to turn on segments A, B, C and DP – which match to the shift register’s outputs 0,1,2,8. 

Thus the byte to send to the shift register would be 0b11100001 (or 225 in decimal or 0xE1 in hexadecimal). 

Every time you want to change the display you need to re-draw all four (or more if more than one module is connected) digits – so four bytes of data are sent for each display change. The digits are addressed from right to left, so the first byte send is for the last digit – and the last byte is for the first digit. 

There are three stages of updating the display. 

  1. Set the LCK (latch) line low
  2. Shift out four bytes of data from your microcontroller
  3. Set the LCK (latch) line high

For example, using Arduino code we use:

  digitalWrite(latchPin, LOW);

  shiftOut(dataPin, clockPin, LSBFIRST, 0b10000000); // digit 4

  shiftOut(dataPin, clockPin, LSBFIRST, 0b01000000); // digit 3

  shiftOut(dataPin, clockPin, LSBFIRST, 0b00100000); // digit 2

  shiftOut(dataPin, clockPin, LSBFIRST, 0b00010001); // digit 1

  digitalWrite(latchPin, HIGH);

This would result with the following:

4digit7segmentdisplaymoduletronixlabsbits

Note how the bytes in binary match the map of the digits and their position. For example, the first byte sent was for the fourth digit, and the segment A was turned on. And that’s all there is to it – a neat and simple display. 

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