How To Use The Tm1637 Digit Display With Arduino

Intro

In my hand is a 4-Digit 7-Segment display module.The heart of this module is an inexpensive Serial LED Driver from Titan Micro Electronics called the TM1637.
In this tutorial, I am going to show you guys how to control the TM1637 4-Digit 7-Segment displays using an Arduino. If you want to displays sensor data, temperature and humidity, or want to design a clock, timer or counter, you will need this 4-Digit Seven-Segment Display.

Topics Covered

In this tutorial we are going to talk about:

The Basics of a 7-Segment Display 

Hardware Overview and Pinout of The TM1637 Module

TM1637 Library Installation

Interfacing TM1637 Module with an Arduino

Loading The Basic Arduino Code (that comes with the TM1637 library)

Then we will have a look at some of these quick examples:

Example 1: Displaying String and a Number

Example 2: Displaying Scrolling and Blinking Text

Example 3: Creating a 4 Digit Counter

Example 4: Displaying Temperature & Humidity using DHT11/DHT22

Example 5: Creating an Arduino Based Digital Clock

And finally we will have a look at some common errors.

7-Segment Display Basics

Hardware Overview and Pinout of TM1637 Module

The module comes with 4 right angle male pin headers. I find it a bit annoying to have the pin headers on the top side of the board. However, you can always unsolder and put them at the bottom of the board.

Now lets have a look at the GPIO pins:

CLK - is the clock input pin. You can connect it to any digital pin of an Arduino.

DIO - is the Data I/O pin. This can also connect to any digital pin of an Arduino.

VCC - Connects to 3.3V to 5V power supply.

GND - is the ground pin.

CLK and DIO pins can be connected to any digital pin of an Arduino. This gives us an opportunity to hook up a lot of these modules to an Arduino, as long as each instance has a pin pair of its own. When writing the code, we just need to specify the pin pair and then just go ahead and use them in your project.

If you run out of pins on your Arduino board you can use a GPIO Pin Extenders like the PCF8574. Please check out my tutorial on the Extender module, the link is in the description below.PCF8574 GPIO Extender: https://diyfactory007.blogspot.com/2018/12/pcf8574-gpio-extender-with-arduino-and.html
The module has 4 x 0.36 segment 7-Segment Displays and a ‘colon’ at the center for creating clock or time-based projects.
A bare four digit 7-Segment Displays usually requires 12 connection pins but the TM1637 LED Driver removes the need of the extra wiring for the 7-Segments and the entire setup can be controlled just by using 2 wires (DIO and CLK) and two more for power reducing the total wires to 4.
These modules communicate with the processor using "I2C-like protocol". The implementation is pure software emulation and doesn't make use of any special hardware (other than GPIO pins).The module operates between 3.3v to 5v with a current consumption of 80ma and allows adjusting the brightness of the LEDs at the software level. They are available in few different colors.

TM1637 Library Installation

You just need to connect four wires: 2 for power and other 2 for controlling the display.

You can connect the VCC of the module to either 3.3v or 5v pin of the Arduino.

So, connect:

CLK - Pin 2 of Arduino

DIO - Pin 3 of Arduino

VCC - 5V    of Arduino

GND - GND   of Arduino

As previously advised, you can use any pin combination for the CLK and DIO on the Arduino board. Just make sure you change the pin numbers in the code to reflect the change of wiring.

So far, based on my experience I have only found one disadvantage.

This module is unable to display floating points or dots between numbers. However, you can use the "HT16K33 module" for displaying floating points.

Loading The TM1637Test Example

#include <TM1637Display.h> #define CLK 2 #define DIO 3

Next, you need to create a new instance of the "TM1637Display" class by passing the CLK and the DIO Pin values to it.

TM1637Display display(CLK, DIO);

Then, the code shows us 2 ways of displaying data on the individual segments by creating arrays of texts.
a. 1st by passing "hexadecimal numbers" to the individual displays

uint8_t data[] = {0xff, 0xff, 0xff, 0xff};

Passing "0xff" to all the 4 displays will turn them all ON, and passing "0x00" will turn them all OFF. Using the "display.encodeDigit()" function you can display digits between 1 and 15.

data[0]= display.encodeDigit(15); // This will display F___ on the display [0b01110001 = F] display.setSegments(data);

This will display F___ on the display.
b. 2nd by individually specifying the segments that you want to turn on. The below creates an array that sets the individual segments values and displays "dOnE" on the display.

uint8_t done[] = {   SEG_B | SEG_C | SEG_D | SEG_E | SEG_G,           // d   SEG_A | SEG_B | SEG_C | SEG_D | SEG_E | SEG_F,   // O   SEG_C | SEG_E | SEG_G,                           // n   SEG_A | SEG_D | SEG_E | SEG_F | SEG_G            // E };

Now, to display these arrays, you need to pass them to the "display.setSegments()" function.

display.setSegments(data); // Will turn off all LEDs display.setSegments(done); // Will display "dOnE"

The setSegments function accepts 3 arguments 

setSegments(data[], length, position);

Data     = The data to display Length   = number of digits to be updated (0–4). Ex. for "dOnE", it will be 4, for the "°C" it will be 2.  Position = determines the position from which you want to print (0-leftmost, 3-rightmost).
Remember, the LEDs once turned on stays on until they are turned off. So, you always have to clear the previous value before displaying the new one. This can be done by passing 4 lots of 0xffto the "display.setSegments()" function or by using "display.clear()" function.

        uint8_t data[] = {0xff, 0xff, 0xff, 0xff}; display.setSegments(data);

The brightness of the display can be adjusted using the "setBrightness()" function. The function accepts values between 0 (lowest) to 7 (highest).

display.setBrightness(3); // Sets the brightness level to 3

The "display.showNumberDec()" function is the  function that you are going to use the most to display numbers on the module. The first argument is a number that you want to display on the screen. The rest of the arguments are all optional. Syntax: 

showNumberDec(number, leading_zeros, length, position);

Number        = The number that you want to display on the screen. Values up to 9999 (type integer). Leading_Zeros = True/false. Setting it to True will add leading zeroes. Default value is false. Length      = number of digits to be updated (0–4). Ex. for "dOnE", it will be 4, for the "°C" it will be 2.  Position    = determines the position from which you want to print (0-leftmost, 3-rightmost). Example:

                display.showNumberDec(1,false)  // Displays ___1 display.showNumberDec(1,false,1,0)  // Displays 1___ display.showNumberDec(1,false,1,2)  // Displays __1_ display.showNumberDec(10,false,2,0) // Displays 10__

Template

Example 1: Displaying Strings and Numbers

• Example1: Download

Example 2: Displaying Scrolling and Blinking Text

• Example2: Download

Example 3: Creating a 4 Digit Counter

• Example3: Download

Example 4: Displaying Temperature & Humidity using DHT11/DHT22

• Example4: Download

Example 5: Creating an Arduino Based Digital Clock

Common Errors

display.clear();

or

uint8_t data[] = {0xff, 0xff, 0xff, 0xff}; display.setSegments(data);

Display data going out of the display or showing partially Check the positioning of the display data.

setSegments(data[], length, position);

These are few of the issues that I came across while playing around with these displays.Do comment and let me know if you have any more to add to the list.

Thanks

Thanks again for checking my post. I hope it helps you.If you want to support me subscribe to my YouTube Channel: https://www.youtube.com/user/tarantula3
Links: 

• Video: Video Link https://youtu.be/Ob9mrq_Lj9k
• Full Blog Post: Blog Post 
• Datasheet: Download
• Schema: Download
• TM1637Display Library: Download
• Thingiverse : Download
• PCF8574 GPIO Extender: Blog Post

Code:

• Example1: Download
• Example2: Download
• Example3: Download
• Example4: Download
• TM1637Test: Download
• Template: Download

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