Note

Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

Why Join?

Expert Support: Solve post-sale issues and technical challenges with help from our community and team.
Learn & Share: Exchange tips and tutorials to enhance your skills.
Exclusive Previews: Get early access to new product announcements and sneak peeks.
Special Discounts: Enjoy exclusive discounts on our newest products.
Festive Promotions and Giveaways: Take part in giveaways and holiday promotions.

👉 Ready to explore and create with us? Click [here] and join today!

7-segment Display

Overview

A 7-segment display is a device that can display numerals and letters. It’s made up of seven LEDs connected in parallel. Different letters/numbers can be shown by connecting pins on the display to the power source and enabling the related pins, thus turning on the corresponding LED segments. In this lesson let’s learn how to display specific characters on it.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Elite Explorer Kit	300+	Elite Explorer Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION	PURCHASE LINK
Arduino Uno R4 WiFi	-
Breadboard	BUY
Jumper Wires	BUY
Resistor	BUY
7-segment Display	BUY

Wiring

Schematic Diagram

In this experiment, connect each of pin a-g of the 7-Segment Display to one 1000 ohm current limiting resistor respectively and then to pin 4-11. GND connects to GND. By programming, we can set one or several of pin4-11 as High level to light up the corresponding LED(s).

../_images/13-7_segment_display_schematic.png

Code

Note

You can open the file 13-7_segment.ino under the path of elite-explorer-kit-main\basic_project\13-7_segment directly.
Or copy this code into Arduino IDE.

Code Analysis

The code may be a little long for this experiment. But the syntax is simple. Let’s take a look.

Call the function in loop()

digital_1(); //display 1 to the 7-segment

delay(1000); //wait for a second

digital_2(); //display 2 to the 7-segment

delay(1000); //wait for a second

digital_3(); //display 3 to the 7-segment

delay(1000); //wait for a second

digital_4(); //display 4 to the 7-segment

Calling these functions into the loop() is to let the 7-Segment display 0-F. The functions are shown below. Take digital_2() for example:

Detailed analysis of digital_2()

void digital_2()  //display 2 to the 7-segment
{
  turnOffAllSegments();
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(d, HIGH);
}

First, we need to understand how the numeral 2 appears on the 7-Segment display. It is achieved by powering on segments a, b, d, e, and g. In programming, pins connected to these segments are set to a High level while c and f are set to Low level. We start by using the function turnOffAllSegments() to turn off all segments and then light up the required ones.

After running this part, the 7-segment will display 2. Similarly, the display of other characters are the same. Since the letters b and d in upper case, namely B and D, would look the same with 8 and 0 on the display, they are displayed in lower case instead.