GreenLock: a site blocker you can only unlock by going outside

Description and use

GreenLock blocks distracting sites after a daily limit and requires users to go outside to unlock, using a local Gemma 3 model to verify outdoor photos.

Problem

Users spend excessive time on distracting sites like YouTube and Netflix, hindering daily step goals and productivity.

Outcome

GreenLock effectively limits screen time, forces outdoor breaks, and integrates step goals without cloud services.

Workflow

• 1. Configure sites and daily time limit in the Chrome extension.
• 2. Track active tab time; when limit reached, extension replaces site with lock screen and QR code.
• 3. Scan QR code with phone, take start photo outside, stay outside for required break time.
• 4. Take end photo outside; phone sends both photos over Wi‑Fi to local Flask server.
• 5. Flask server runs Gemma 3 locally to verify photos were taken outdoors.
• 6. If both photos pass, server unlocks sites and redirects user back to original page.

Evidence

GreenLock is a Chrome extension that locks your time‑wasting sites once you hit your daily limit, and the only way to get them back is to go outside.

Source

Your phone sends each photo over Wi‑Fi to the Flask server on your computer, where a Gemma 3 vision model running locally in Ollama checks it.

Source

The photo check was also really slow at first, around 30 seconds, which is way too long when you're standing outside waiting. We added timing logs and found out the AI wasn't even the main problem, it was uploading the full‑size photo from the phone.

Source