moth by daylight noise

moth

it does its sums out loud

20 HP

Eight real relays do your logic with little metal arms, so every gate clicks in your case, and a piezo hands you the clatter as a drum machine playing whatever the logic is doing. There's a real moth on a wire over them. Drag it along and each relay throws as it passes; leave it and that one's stuck.

Eight relays

The left four listen and the right four answer. Each of the eight is a real contact that really moves and really carries the signal, so the gates that come out have real bounce on them, and they arrive a few milliseconds late. Under each relay a pair of lit legs shows you which way its arm is thrown.

The module reads its own contacts, not what it told them to do, so a relay that doesn't move is wrong for everything after it. An empty input takes the relay to its left. With A empty the row comes round into a ring, and whatever's in it keeps going.

A, B, C, D: gates in. Each moves its own relay.

WIRING: a five-stop switch. On the first three each answer takes the one before it with one more relay: AND dies away in a ring, OR fills it up, XOR keeps what you gave it, round and round. On the fourth, NOT, each answer is the opposite of its letter, and with nothing patched the row chases itself for ever. The last is STEP.

CLOCK: empty, the relays move when they're told to. Patched, the whole row moves only on a pulse.

The clatter

A piezo on the board hears every landing. Each relay sounds a little different, the near ones low and the far ones dry, so the row is a small kit, and it plays whatever your logic is doing.

CLATTER: how loud it is. Fully left, nothing. Fully right the amp's well past clean, the board's own low notes come up under every landing and the case is the drum.

RATTLE: fully left a relay closes once. Up from there it buzzes after it closes, its coil fed through its own contact. Fully right that's a third of a second at about 150 Hz, and it goes out of the rungs as real gates.

DELAY: how long each relay waits, and each waits for the last. At noon it's a flam. Fully right it's a quarter of a second a relay, so one gate walks the length of the row. With nothing clocking it, this is the only tempo the ring has.

The moth

The one on the wire is real: there's a magnet in it. Each relay it passes throws, with no signal at all, and you feel it tug at each one. Let go and it settles. At home on the spine it's over nothing; anywhere else that relay can't let go, and it stays that way until you move it. A quick dab writes a bit into the ring.

MOTH: how many others have got in. Fully left, none. Turned up, now and then a relay sticks by itself and a very small moth lights under it. Well up the logic can't be trusted, and limbs come and go. Fully right the row seizes up, a relay at a time, and stays that way until you clear it.

CLEAR, and its gate: everything stuck lets go, the row starts clean, and every relay throws. It can't shift the moth on the wire. That takes a hand.

Four ways

WIRING's last stop is an honest sequential switch. A to D take anything, audio or CV, and one at a time goes through a real contact to LINE, galvanically clean, with the small tick of a relay on each step. LINE is a wire, so it works backwards too: send one signal into it and A to D take turns. With a moth on one of them, two share the line.

What comes out

RUNG 1: D with A, on the first three stops. On NOT, the opposite of A.

RUNG 2: RUNG 1 with B. On NOT, the opposite of B.

RUNG 3: RUNG 2 with C. On NOT, the opposite of C.

RUNG 4: RUNG 3 with D. On NOT, the opposite of D. On STEP each rung is high for its own step.

LINE: whatever of A to D is closed.

CLATTER: what the piezo hears.

Specs

Format

Width: 20 HP
Controls: a moth on a wire, 4 knobs, a 5-stop switch, a button

Inputs

A to D: A, B, C, D: gates, rising past 1 V; on the last stop, anything
CLOCK: gate, rising past 1 V
CLEAR: gate, rising past 1 V

Outputs

RUNG 1 to 4: RUNG 1, RUNG 2, RUNG 3, RUNG 4: gates, 5 V, through real contacts
LINE: a wire, through real contacts
CLATTER: audio, ±5 V