Interfacing Seven Segment Display With Arduino - Circuit Digest

Nowadays, visual indication is a must-have feature for any electronic device, which will make user interaction much easier. There are multiple ways to implement the visual indication, from simple light indications to LCDs or even holograms. Today, we will be talking about such a device, which has been used in the industry for decades – the Seven Segment Display. The 7 segment display Arduino interface is one of the most fundamental projects for electronics beginners. In this comprehensive tutorial, you'll learn everything about 7 segment display Arduino code, circuit connections, and practical applications.

The seven segment displays are designed for displaying numeric values. You can find them anywhere, from instruments to space shuttles. They are the most practical way to display numeric values in your Arduino Projects. They are cheap and easy to use. Not only that, they are highly readable in any light condition, unlike LCDs. You can find them in many everyday usages, like counters or token systems, etc.

Table of Contents

• Required Components
• Understanding 7 Segment Display Pinout
• Types of Seven Segment Displays
• Truth Table
• TinkerCAD Simulation
• └ Benefits of TinkerCAD Simulation
• Circuit Diagram
• Arduino Code
• └ Method 1: Using the SevSeg Library
• └ Method 2: Manual Control
• GitHub Repository
• Troubleshooting

Required Components

Component	Quantity	Specifications	Purpose
Arduino Uno	1	ATmega328P based	Microcontroller board
7 Segment Display	1	Common Cathode/Anode	Display unit
Resistors	8	330Ω	Current limiting
Breadboard	1	Full size	Circuit connections
Jumper Wires	10+	Male to Male	Connections

And here is a small simulation showing the Seven Segment Interface. The Arduino will count from 0 to 9 and repeat. The value will be displayed on the seven-segment display. Seven-segment displays are available in various sizes and colours. They are available from 0.28 inches to 18 inches, and even bigger sizes are available for industrial usage. The most commonly used display size is 0.56 inches.

Understanding 7 Segment Display Pinout

The 7 segment display pinout is crucial for proper Arduino interfacing. As the name suggests, the seven-segment display consists of seven LEDs, which are arranged in a particular order to form the digit eight. And most common modules will come with an additional LED to indicate the decimal point. This will be useful when using multiple display modules to display a decimal number. Each one of these LEDs is arranged in a specific order as a segment, and one of its pins is brought out of the plastic package. The other LED pins are connected and wired to form a common pin.

Standard Pin Configuration

• Segments A-G: Individual LED anodes/cathodes for each segment
• Common Pin: Shared connection for all LEDs (pin 3 or 8)
• Decimal Point (DP): Additional LED for decimal indication

By forward-biasing the appropriate pins of LED segments in a particular order, we can generate the character pattern of a desired number on the display. The 7 segment display Arduino working principle allows us to display the numbers from 0 to 9 on the display. In the above image, we have highlighted the eight data pins in green and the common pin in pink.

Types of Seven Segment Displays

Seven segment displays are mainly categorised into two types, Common Cathode (CC) and Common Anode (CA). This classification is done based on which pin of the LEDs is connected to the common pin. If the Anodes of these LEDs are connected, then it’s called a Common Anode display. And if the Cathode is connected, then they are called Common Cathode displays.

Common Cathode Displays

In a Common Cathode (CC) display, all the cathodes of the LEDs are connected to the common pin. This common pin is then connected to the ground rail of the circuit. The individual LEDs can be activated by applying a high pulse or a logic 1 signal to the corresponding pin.

In the above image, you can see the basic working of the seven-segment. The common pin is connected to the GND, and each data pin is connected to VCC through a switch. When a switch is pressed, the corresponding LED will be forward-biased, and the segment will light up. On the right side, you can see the simplified diagram of a seven-segment display.

Common Anode Displays

In a Common Anode (CA) display, all the anodes of the LEDs are connected to the common pin. This common pin is then connected to the positive rail of the circuit. The individual LEDs can be activated by applying a low pulse or a logic 0 signal to the corresponding pin.

In the above image, you can see the basic working of the seven-segment. The common pin is connected to the VCC, and each data pin is connected to GND through a switch. When a switch is pressed, the corresponding LED will be forward-biased, and the segment will light up. On the right side, you can see the simplified diagram of a seven-segment display.

Seven Segment Display Truth Table

To display a number or pattern, we must activate the corresponding pins with the appropriate signal, i.e. for Common Cathode display Logic 0 or LOW and for Common Anode display Logic 1 or HIGH. By this method, we can display various digits from 0 to 9. Here is the character map for each character.

And here is the truth table for the Common Cathode display. For the Common Anode display, the signals will be inverted.

Even though the seven segments are designed to display numbers, we can also display letters using them. Here is the truth table for the alphabet.

7 Segment Display Arduino TinkerCAD Simulation

Let’s simulate the circuit on ThinkerCAD before testing it on the breadboard. Here is the Thinkercad simulation for interfacing the seven-segment display with Arduino. Before building the physical circuit, test your 7 segment display Arduino TinkerCAD simulation.

Click on the start simulation button to test the circuit. The Tinkercad code for the interfacing seven-segment display with Arduino will show numbers 0-9 on the display. If you want to edit the code, please click the code button and modify as needed.

Benefits of TinkerCAD Simulation

• Evaluate circuit performance before creating real hardware.
• Troubleshoot software bugs in a safe environment.
• Try with varying values for components.
• Publish your created projects for the community.
• Engage in a more hands-on learning of Arduino programming.