Re:I made a thing to help you make a thing out of a keypad
by lelanthran on Friday April 12, 2024 @04:16AM
(#40010431)
> 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.
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.