A clever indie dev repurposed the Apple Silicon accelerometer into an invisible interface. Tap your Mac or desk to run commands. But what if your cat steps on it?
Ever got so frustrated writing spaghetti code that you just wanted to aggressively knock on your Mac's chassis, and somehow wish it would automatically git commit your mess? Well, over on Product Hunt, some mad lad actually turned knocking into a literal feature.
The app is called Knock, built by an indie dev named Will Gee. The guy realized that Apple Silicon MacBooks come with a built-in accelerometer that basically sits there doing nothing 99% of the time, besides sensing if your laptop is taking a dive off the table. So, he hijacked the sensor data to create a physical trigger.
Once installed, you can literally tap on your MacBook's chassis or the desk next to it to switch tabs, change desktops, pause your lo-fi beats, launch apps, or run your own custom bash scripts. It feels like casting a spell. It's an "invisible interface"—no need to memorize another complex keyboard shortcut combo that requires breaking your fingers.
The app grabbed a solid 119 upvotes on its PH launch. Productivity nerds are loving the vibe—it’s perfect for triggering Focus Mode without breaking your flow. Just tap the desk and boom, Slack notifications are silenced.
But of course, the QA mindset in the dev community kicked in immediately. One user brought up the ultimate edge case: "My cat paws aggressively at my laptop hinge. Is this gonna trigger random stuff?" Will had to admit that feline percussion is a tough one to crack. However, he explained that the app is trained to look for short, sharp impulse spikes rather than general wobbling.
To prevent accidental triggers, there’s a sensitivity slider so you can tune it for your specific desk material. More importantly, gestures are suppressed while typing—so you won't accidentally switch desktops while rage-typing a PR comment. Another paranoid user asked if knocking ruins the Mac hardware long-term. Will reassured everyone that the app just passively reads sensor data. Unless you're hitting your Mac with a hammer, it's perfectly safe.
Wrapping this up, Knock is a prime example of the real hacker mentality. While half the tech world is busy shipping generic AI wrappers to farm funding, this guy looked at a dormant hardware sensor and thought, "I can make this do cool sht."*
The lesson here for all of us keyboard warriors? You don't always need complex tech stacks, microservices, or buzzwords to build something valuable. Sometimes you just need to creatively use what's already sitting right in front of you. Now, excuse me while I go map a "double-knock" gesture to force-quit all my StackOverflow tabs.
Source: Knock - Product Hunt
