DIY 7 Segment Display

Hello everyone,

Welcome to this instructable. I am gonna share you how to make a very cheap and simple seven segment display. Seven segment display is a numeric display that can display numbers from 0 to 9. The display consists of seven segments and we can simply display any number by turning on LEDs associated with each segment.

For example, Turning on the segments A, B, G, C, and D will display the number "3".

Each of the seven segments has an LED associated with it and there are seven LEDs in total. Sometimes their negative leads are connected together and such displays are called common cathode display and called common anode displays when their positive leads are connected together.

I am explaining here a common cathode type seven segment display.

For better intro and basics Refer:

https://en.wikipedia.org/wiki/Seven-segment_displa... and

http://www.electronics-tutorials.ws/blog/7-segment-display-tutorial.html

This is a low-cost DIY and requires a few pieces of stuff:

• Perf board/ Universal PCB.
• LEDs.
• Male Headers.
• Some wires.

In the circuit diagram, there are seven pairs of LEDs placed in order. The two LEDs are connected in series in each pair. We call the seven pairs as a, b, c, d, e, and f.

The negative part of each pair is connected to a common ground or we can call it as the common cathode. And the positive ends of them are called a, b, c, d, e, and f.

For displaying the number "1", connect voltage to "b" and "c" with respect to GND. And connecting voltage to pins "d", "e", "f", "g", and "a" will display the number "3".

Now make the circuit by soldering the LEDs as pairs in position as shown.

• Solder the first pair of LEDs and connect the negative pin of one to the positive of the other.
• Solder all the seven pairs like this.
• Join all the seven negative ends together.
• Now connect the 8 pin male header as shown.
• Connect the positive end of the LED pair "a" to the first pin of the header.
• Connect the positive end of the LED pair "b" to the next pin and so on.
• After connecting all the seven positive ends, connect the common ground to the last(8th) pin of the header.

An Arduino board is needed to know how it does work.

I used Arduino Uno here.

• Set up the Arduino Uno.
• Connect the common ground of the LED display to the ground of the Arduino board.
• Connect the pin number 7 of the Arduino to the pin "a" of the display.
• Connect the pin number 8 of the Arduino to the pin "b" of the display and similarly pin number 9, 10, 11, 12, and 13 to the next pins of the display.
• Connect the Arduino board to the computer, copy the code and visualize the display counting 0 to nine.

Thanks for your time.

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