Show HN: I built an app to use a QR code as my doorbell

Original Article ↗ Hacker News Discussion ↗

Overview of the idea

  • App generates a QR code to stick on a door; visitors scan it, optionally take a photo/selfie, and the app notifies the resident’s phone, potentially even when they’re away.
  • Some see it as a clever, fun hack / weekend project or a cheap, privacy-friendlier alternative to full smart doorbells.

UX vs. traditional doorbells / knocking

  • Many argue UX is worse than:
    • Pressing a physical button.
    • Knocking.
    • Calling/texting when you arrive.
  • Scanning a QR requires: pulling out phone, opening camera/app, scanning, interacting with a page/app, possibly dealing with permissions. Seen as too much friction, especially for delivery drivers and casual visitors.
  • Critics say it excludes people without smartphones, kids, some elderly, and those who dislike QR-code-heavy experiences (e.g., restaurants).

Use cases and niche scenarios

  • Suggested scenarios where it may make sense:
    • Homes or rentals without existing doorbells / wiring.
    • Long driveways or doors far from living areas.
    • Offices or meetups where the physical intercom rings in the wrong place or nobody is at reception.
    • Temporary event spaces without bells.
    • As a “virtual doorbell” for parties or offices, or for remote “pokes” between friends.
  • Several note cheap wireless doorbells (~$5–$30) already solve most basic problems with less friction.

Security, privacy, and abuse concerns

  • Static QR code can be copied, shared online, swapped between neighboring houses, or overlaid with malicious codes (phishing, rogue apps).
  • Worst case: remote “ding-dong-ditch” / DoS of notifications.
  • Some propose mitigations: periodically rotating codes (possibly with e-ink), location checks, one-time pins, CAPTCHAs, or geofencing—others see this as overengineering.
  • Debate on QR safety: some equate risk with any web link; others stress lack of human-readable cues and ease of code tampering.
  • Some prefer this over camera doorbells due to surveillance/privacy concerns; others dislike being asked for photos at all.

Accessibility and inclusivity

  • Smart notifications can help people with hearing loss or those who can’t always hear the chime, but many argue a simple button plus smart notifier is better.
  • Concern that QR-first design burdens visitors instead of adapting infrastructure for residents.

Implementation and product feedback

  • UI criticized as confusing (immediate camera access request, no explanation, camera-switch issues).
  • Suggestions: explain permissions before asking; use <input type="file" capture>; consider NFC tags or iOS App Clips; support text/notes; open protocols (e.g., ntfy-style) or open source.
  • Product positioning: better framed as “create a doorbell where none exists” or for special contexts, not “replace your doorbell with a QR code.”