Workshop on LED Displays with Arduino

Introduction

• Focus on using Arduino with LED displays: seven-segment and dot matrix.
• Exploration of display libraries to simplify coding tasks.
• Historical context: LED displays popularized in the 1970s for digital clocks, watches, and calculators.

Advantages and Limitations of LED Displays

• Advantages:
  • Low cost and reliable.
  • Long lifespan and durability.
  • Visibility in dark and broad daylight, wide viewing angles.
  • Variety of colors and sizes.
• Limitations:
  • High current consumption, not ideal for battery-powered devices.
  • Limited character display capacity.
  • Filters or bezels often needed for best viewing.

Types of LED Displays

Seven-Segment Displays

• Comprise seven individual LEDs to display numbers and some letters.
• Configurations:
  • Common cathode: LED cathodes are grounded.
  • Common anode: LED anodes tied to voltage source.
• Resistors:
  • Individual resistors for each segment (220-470 ohms for 5V supply).
  • Single resistor on common side (820-1.5k ohms).
• Coding and Circuits:
  • Truth tables for character display.
  • Libraries like SevSeg simplify interfacing with Arduino.

Dot Matrix Displays

• Composed of an 8x8 matrix of LEDs, useful for text and symbols.
• More versatile than seven-segment displays.
• Often used with chips like the MAX 7219 for serial data conversion.

Using Arduino with LED Displays

Seven-Segment Display with Arduino

• Setup:
  • Connect individual segments to Arduino pins via resistors.
  • Use SevSeg library for easy control.
• Experiments:
  • Display single digit numbers.
  • Implement a counter from 0-9.

Multiplexed Displays

• Four-Element Display:
  • Multiplexing cuts down on number of connections.
  • Common cathode/anode connections for multiplexing.
• Code Example:
  • Use SevSeg library for multiple digit displays.

Using MAX 7219 with LED Displays

• Purpose:
  • Converts serial data to control multiple LEDs.
  • Allows cascading multiple displays.
• Setup:
  • Requires fewer connections: data in, load, clock.
  • Libraries: Joins like Max 7219 by Jonathan Evans, LED Control.

Dot Matrix Displays

• Setup:
  • Often used with MAX 7219 for driving 8x8 matrix.
  • Requires external power supply for adequate current.
• Libraries:
  • Play with libraries like MD Parola for text and animations.
  • Example sketches available for advanced effects.

Conclusion

• LED displays offer versatility for Arduino projects.
• Considerations for power supply and connection requirements.
• Many library options to explore for custom applications.

Additional Resources

• Visit the Dronebot Workshop website for articles and code.
• Join the Dronebot Workshop Forum for discussions.