Clap Music for two flip-disc displays

September 14, 2024

I present to you: by Steve Reich Applause Musicas done by a pair of flip-discs shown:

Read on for its origin…

Down the flip-disc rabbit hole

A few years ago, I became obsessed with flip-disc displays and art is made with them:

Because of this, my partner gave me a pair AlphaZeta boards: a 7×28 flip-dots display, and a 7×4 seven-segment flip-digit (“Vane”) display. We put them in our living room and programmed them to show the date, the current outside temperature, and the current weather (preceding upcoming rain), updated every half hour.

Our show has been running for almost three years at this point, with very little intervention (for example, a manual restart after a power outage). This makes me so happy! Two unexpected benefits:

1. My internal temperature mapping (Fahrenheit) of the clothes I wear before going out? BETTER.

2. Passive awareness of the clock, as the shickshick The hourly / half hourly update is a nice reminder that I need to jump into that meeting / get off the bus / think about going to bed.

The source of that mysterious noise

One of my favorite things about electromechanical performances is how visceral they are — that little “chk!” when changing state. The two performances are different from each other: while one dot makes a slow snick, so updating several dots produces a whirring noise, one part of the other digit makes a sharper clack, and a fast update of the digits creates an aggressive clacking too.

Once we were successfully sending commands to the boards (a victory in its own right!), I started playing basic rhythms with them. I sent a video of a beat to a
musician/composer friendwhose immediate response was

They are correct: I DOING it should be done with clapping music. Immediately. 😀

clapping Flip the music

by Steve Reich
Applause Music

is a composition in which two performers (or sets of performers) repeatedly clap a 12-beat pattern. After eight or twelve repetitions, the second performer moves their position in the pattern back one beat. This process is repeated until the second performer returns to playing the original no-offset pattern. Shifting the offset causes a pleasing phasing effect for listeners.

Here is the clapped pattern:

and another very nice visualization of its performance:

The code for doing this with two flip-disc displays is fairly simple:

function _clapping_music(sink_dots, sink_digits; pause=0.15,
                         clap_pattern=Bool(1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0),
                         num_repeats=12, num_shifts=length(clap_pattern) + 1,
                         num_dots_to_set=28, num_digits_to_set=2)
    i_pattern_shift = 0
    for _ in 1:num_shifts
        for _ in 1:num_repeats, i_pattern in eachindex(clap_pattern)
            clap_pattern(i_pattern) &&
                write_to_sink(sink_dots, rand(0x00:0x7F, num_dots_to_set))
            clap_pattern(mod1(i_pattern + i_pattern_shift, length(clap_pattern))) &&
                write_to_sink(sink_digits, rand(0x00:0x7F, num_digits_to_set))
            sleep(pause)
        end
        i_pattern_shift += 1
    end
end

# Variant A
clap_pattern = Bool(1, 0, 0, 1, 1, 1)
pause=0.12
num_repeats=2
num_dots_to_set=14
num_digits_to_set=4

# Variant B
clap_pattern = Bool(1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0)
pause=0.15
num_repeats=2
num_dots_to_set=28
num_digits_to_set=14

The full code for this display—including set up instructions—is available on GitHub. Thanks to AF for filming the examples here, and to Cosmo for putting up with us being annoying while he tries to sleep.

• Created: 2024-09-14
• Last updated: 2024-09-14
• Type: Writing project
• Tags: electromechanical-display, raspberry-pi, music, programming, hardware, software, julia