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Arduino - 7-segment Clock
In this tutorial, we are going to learn how to make 7-segment clock using Arduino. In detail, we will learn two cases:
- Arduino reads time (minute and second) from DS3231 RTC module and display it on the TM1637 4-digit 7-segment module
- Arduino reads time (hour and minute) from DS3231 RTC module and display it on the TM1637 4-digit 7-segment module
You can also use the DS1307 RTC module instead of the DS3231 RTC module by changing a single line of code. See DS3231 vs DS1307
Hardware Required
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.
About TM1637 display, DS3231 and DS1307 RTC modules
If you do not know about TM1637 7-segment display, DS3231 and DS1307 (pinout, how it works, how to program ...), learn about them in the following tutorials:
Install TM1637 and RTC Libraries
- Navigate to the Libraries icon on the left bar of the Arduino IDE.
- Search “TM1637”, then find the TM1637Display library by Avishay Orpaz
- Click Install button.
- Search “RTClib”, then find the RTC library by Adafruit. This library works with both DS3231 and DS1307
- Click Install button to install RTC library.
- You may be asked for intalling some other library dependencies
- Click Install All button to install all library dependencies.
Wiring Diagram
- The wiring diagram between Arduino, TM1637 4-digit 7-segment display and DS3231 RTC module.
This image is created using Fritzing. Click to enlarge image
- The wiring diagram between Arduino, TM1637 4-digit 7-segment display and DS1307 RTC module.
This image is created using Fritzing. Click to enlarge image
Arduino Code - Displaying minute and seconds on the 7-segment display
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-7-segment-clock
*/
#include <TM1637Display.h>
#include <RTClib.h>
// define the connections pins
#define CLK 9
#define DIO 10
// create a display object of type TM1637Display
TM1637Display display = TM1637Display(CLK, DIO);
RTC_DS1307 rtc;
// RTC_DS3231 rtc; // uncomment this line and comment the above line if using DS3231 module
unsigned long time_m = 0; // the variable to store minute
unsigned long time_s = 0; // the variable to store second
unsigned long last_s = 0; // the variable to store the last updated second
void setup() {
Serial.begin(9600);
display.clear();
display.setBrightness(7); // set the brightness to 7 (0:dimmest, 7:brightest)
// SETUP RTC MODULE
if (!rtc.begin()) {
Serial.println("Couldn't find RTC");
Serial.flush();
while (true)
;
}
// automatically sets the RTC to the date & time on PC this sketch was compiled
rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
}
void loop() {
DateTime now = rtc.now();
time_m = now.minute();
time_s = now.second();
if (time_s != last_s) { // only update if changed
unsigned long time = time_m * 100 + time_s;
display.showNumberDecEx(time, 0b11100000, false, 4, 0);
Serial.print(time_m);
Serial.print(":");
Serial.println(time_s);
last_s = time_s;
}
}
Quick Steps
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to Arduino
- Check out the result on the Serial Monitor and TM1637 display.
Code Explanation
Read the line-by-line explanation in comment lines of source code!
If you want to use the DS1307 RTC module instead of DS3231 RTC module, you just need to commment/uncomment a line specified in the code
Arduino Code - Displaying hour and minute on the 7-segment display
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-7-segment-clock
*/
#include <TM1637Display.h>
#include <RTClib.h>
// define the connections pins
#define CLK 9
#define DIO 10
// create a display object of type TM1637Display
TM1637Display display = TM1637Display(CLK, DIO);
RTC_DS1307 rtc;
// RTC_DS3231 rtc; // uncomment this line and comment the above line if using DS3231 module
unsigned long time_h = 0; // the variable to store hour
unsigned long time_m = 0; // the variable to store minute
unsigned long last_m = 0; // the variable to store the last updated hour
void setup() {
Serial.begin(9600);
display.clear();
display.setBrightness(7); // set the brightness to 7 (0:dimmest, 7:brightest)
// SETUP RTC MODULE
if (!rtc.begin()) {
Serial.println("Couldn't find RTC");
Serial.flush();
while (true)
;
}
// automatically sets the RTC to the date & time on PC this sketch was compiled
rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
}
void loop() {
DateTime now = rtc.now();
time_h = now.hour();
time_m = now.minute();
if (time_m != last_m) { // only update if changed
unsigned long time = time_h * 100 + time_m;
display.showNumberDecEx(time, 0b11100000, false, 4, 0);
Serial.print(time_h);
Serial.print(":");
Serial.println(time_m);
last_m = time_m;
}
}
Video Tutorial
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