Eyeball - a curious eye in your toolbar

A tiny Chrome extension (Manifest V3) that puts a single eye in your toolbar. The pupil tracks your cursor on the active page. On pages it can't read (PDFs, the Chrome Web Store, chrome:// pages), the eye centers. No network, no tracking.

Features

• Single-eye toolbar icon that follows the cursor on the active page.
• Holds the last pose when the cursor stops on a supported tab, and centers when the active tab is unsupported (PDF viewer, internal Chrome pages, the Web Store).
• Sleeping eye when the browser window loses focus.
• Spontaneous blinks every 7-13 seconds while the eye is actively tracking, plus a soft heartbeat blink about once a minute. Clicking the icon also blinks it.
• Night mode during the evening hours (21:00-06:00, on your local clock) the eye gets tired - the white turns faintly pink and it blinks more often - then it's rested again by morning.
• No popup, no UI surface beyond the toolbar icon. This is a pure toolbar experiment.
• No network, no analytics, no accounts, no tracking. Cursor coordinates are converted to an angle and distance on-device and used only to pick which pre-rendered sprite to show.

Why a single eye

The toolbar icon is 16 px at standard density. Two eyes side by side give each eye only ~7 px - the pupil can move maybe one pixel, which doesn't read as tracking. One eye keeps enough pupil travel that the motion is clearly intentional, and it makes a stronger logo.

Install from source

1. Generate the icons: npm run icons
2. Open chrome://extensions in Chrome.
3. Enable "Developer mode" (top right).
4. Click "Load unpacked" and select the project folder.
5. Move your cursor on any tab - the toolbar eye should follow it.

How it works

At install time, the service worker pre-renders 18 eye sprites (16 directional pupil positions + a centered pose + a closed pose) at 16 px and 32 px, caching each as ImageData. A content script on every page throttles mousemove to ~10 Hz, converts each cursor position to a viewport-relative (angle, magnitude) pair, and sends it over a long-lived chrome.runtime.connect Port. The service worker maps the angle to one of the 16 buckets and calls chrome.action.setIcon({ imageData }) - but only when the bucket actually changes, and never more often than ~25 Hz.

The brand icon (icons/icon{16,32,48,128}.png) is generated analytically by scripts/make-icons.mjs with no external dependencies - a small PNG encoder built on Node's zlib.

Night mode

In the evening (21:00-06:00, your local clock) the eye gets tired: the white turns faintly pink, as if you have been working late, and it blinks a little more often. The iris and pupil are unchanged. It's rested and back to normal by morning.

The switch is driven entirely by your device's clock. Nothing is sent anywhere, and no schedule or preference is stored.

States

State	Trigger	Behavior
open	Default - the active tab has a connected content script	Pupil follows the cursor; freezes at the last pose when the cursor stops; centers when the active tab is unsupported (PDF, chrome://, Web Store)
sleeping	Browser window unfocused	Eye closed
blinking	Spontaneous (every 7-13 s while tracking), a soft heartbeat about once a minute, and toolbar-icon click	Brief eye-closed frame, then back to the last pose

Permissions

Permission	Why it is needed
alarms	Periodic soft blink.
<all_urls> (host)	Lets the content script read cursor position on the active page so the eye can follow it.

Eyeball reads only mousemove coordinates from the active page. It does not read page content, form data, URLs, history, cookies, or anything else. See PRIVACY.md.

Development

npm test     # runs the eye.js unit tests (node --test)
npm run icons  # regenerates icons/*.png
npm run package  # builds dist/eyeball-v<version>.zip for the Chrome Web Store

License

Apache-2.0. Copyright 2026 Konstantin Komelin.