MacTap

MacTap’s knock mappings (image: project promotional material). MacTap is a macOS menu bar utility that maps one, two or three knocks on a MacBook’s chassis–or the desk underneath a stationary laptop–to shortcuts. It supports separate left/right mappings, presets and per-application actions for tasks such as copy and paste, screenshots and media controls. It requires macOS 14.6 or newer and a supported MacBook exposing its motion sensor as an SPU HID device. The README lists M2 and later and some M1 Pro/Max/Ultra hardware, but excludes the original M1 MacBook Air. Sensor compatibility needs checking–Apple Silicon alone is no guarantee. Accessibility permission is needed to send shortcuts, not to detect knocks. Classification runs on-device and gesture mappings stay local. The source code is available under the MIT license.