monomeControllers
Four-encoder knob controller with LED rings
The arc is a USB controller from monome, first released in 2011, made of high- resolution rotary encoders each surrounded by a ring of 64 LEDs. Current models have 1024 ticks per revolution and 16-step LED brightness, and earlier editions came in two-knob and four-knob sizes. It does nothing on its own: the application it is connected to, such as one running on a computer, norns, ansible or crow, defines how movement maps to sound and light.
Only the 2025 arc with a pushbutton supports monome's iii scripting firmware, and it ships with it, so no separate install is needed; older arcs keep their stock firmware and can use the viii browser emulator for iii scripts. Arc is also used with norns, ansible and crow, and a protocol-compatible DIY clone has its own open firmware.
monome's iii firmware for the 2025 arc, which has a pushbutton: standalone Lua scripts on the arc itself, USB-MIDI and a serial REPL, with a serialosc mode for use with norns, ansible and computers.
Open hardware and ATmega88p firmware for a protocol-compatible DIY clone of the monome arc that works with serialosc, flashed with an AVR ISP programmer.