A small interface board for the legendary HP 5082-7415 and 7405 DIP bubble display. by Yannick (Gigawipf):
This project describes a breadboard friendly breakout board with 2 shift registers and resistors for these modules with dip socket to be gentle on these rare displays from the 70s. One shift register controls the anodes and one the cathodes like most modern 7 segment modules.
These rare 7 segment displays once used in HP calculators are still quite impressive if you are lucky enough to find some. Yes they are inefficient. But nothing compares to the deep red glow of those sharp and tiny GaAsP LED segments.
This interface board features 8 current limiting resistors for the segments and two tiny latched qfn shift registers. One for the anodes and one for the cathodes. This makes it simple to interface with modern microcontrollers (Example arduino sketch provided in files). The left one is a 7415 and the right one the 7405 with the centered dot.
Mike is the founder and editor of Electronics-Lab.com, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)
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