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Project Notes

#584 HPDL-1414

Test driving a retro HPDL-1414 4-digit GaAsP display with an Arduino.


Here’s a quick demo..



The HPDL-1414 is a smart, four character, sixteen-segment, red GaAsP display. The on-board CMOS IC contains memory, ASCII decoder, multiplexing circuitry and drivers.

  • Supply Voltage : 4.5-5.5V
  • Macimum current: 90mA
  • Character height: 2.85 mm (0.112”).

The real beauty of this “old fashioned” display is the immersion lens that magnifies the red GaAsP segments nicely.

Module Connection

Function HPDL1414 Pin Arduino Pin
D5 1 D7
D4 2 D6
!WE 3 A0
A1 4 A2
A0 5 A1
Vcc 6 5V
D0 8 D2
D1 9 D3
D2 10 D4
D3 11 D5
D6 12 D8






Using the HPDL1414 Arduino Library.

The character set is quite limited, and custom glyphs are not supproted


Credits and References

About LEAP#584 LED
Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

The projects are usually inspired by things found wild on the net, or ideas from the sources such as:

Feel free to borrow liberally, and if you spot any issues do let me know. See the individual projects for credits where due. There are even now a few projects contributed by others - send your own over in a pull request if you would also like to add to this collection.