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Raspberry Pi LED Blueprints by Agus Kurniawan

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Chapter 2. Make Your Own Countdown Timer

In this chapter, we will learn how to work with a 7-segment display. Then we will build a countdown timer. The basics of 7-segment display programming will be introduced. Furthermore, we will learn what a shift register is and how to use it to enhance the handling of several 7-segment display modules.

From this chapter, you will learn the following topics:

  • Introducing a 7-segment display
  • Introducing a shift register
  • Driving a 7-segment display using a shift register
  • Working with the 4-digit 7-segment display
  • Building a countdown timer

Introducing a 7-segment display

In general, a 7-segment display consists of seven LEDs, and an additional LED is used for a dot (DP pin). This then allows us to display each of the ...

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