I’m about to start working on a project that involves a long string of LED’s used to light up the keys on a full piano. I plan to control what keys are lit up using software on my PC. This will be my first Arduino project, and I’ve looked at tutorials like this:
For driving many LED’s. In this care I’ll probably have around 50-60 LED’s I want to control. Am I best daisy-chaining these LED shift register chips or is there a better way? If I should use these chips, where’s the best place to buy them? (Are there any free samples)?
Thanks so much.
Rather than making a chain of 50-60 of them (why not 88?) you’d be better off creating a matrix. The easiest way is probably to consider each octave a column, and each key within an octave a row. To light a key, make row high and column low. This is similar to the “LED Cube” strategy. That way you’ll only need (rows+columns) pins/bits - 12+8 for a standard 88 (7 octaves plus). That’s 20, so you’ll need a chain of three 595s, and three bytes/shifts.
Shift registers are cheap - like $1.50 for 8 bits. You might also consider a MAX7219, though it’ll only drive 64 (8x8) bits.
You’re going in the right direction, tho.