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Huh, weirdly I was just searching for solutions for this just few days ago - I've got some ESP32 projects with keypads and LCDs, which usually are wired little further away from the ESP and other attachments, so the wiring is somewhat PITA. This thing could help it go from 12 wires total for both LCD+keys to only 4 using shared I2C wiring, quite nice!

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> This thing could help it go from 12 wires total for both LCD+keys to only 4 using shared I2C wiring, quite nice!

Or you could use shift registers which cost a few USD cents.

On a personal project a long long time ago, I recall using daisy-chained shift registers to control a stupidly high number of relays (think 100+), at an extra BOM cost of around $1.

The relay switching time was still much, much larger than the time it took to bit-bang the daisy-chained shift registers for all relays.

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