IdeaWell

Project ideas from Hacker News discussions.

Smartphone LED detects hidden cameras with AI

Original Article

Hacker News Discussion

📝 Discussion Summary (Click to expand)

1. Feasibility of using phone cameras to spot hidden lenses
Commenters noted that a phone’s camera can reveal hidden cameras by glinting off the lens or by seeing infrared (IR) emissions.
- “this works by looking at the physical characteristics of the lens, so on or off should work regardless” – zack6849
- “It'll happily show you IR (just point it at your remote control with the camera active, and press some buttons…” – TheRealPomax
- “You don't need this to detect smart glasses, they're very obvious.” – thesuitonym (shows the idea extends to other covert optics)

2. Limitations imposed by phone IR filters and hardware variability
Many pointed out that built‑in IR‑blocking filters greatly reduce the usefulness of a phone for IR‑based detection, and performance varies by model and camera (front vs. rear).
- “Most quality phones will use a camera with IR filters on them - blacks look like blacks.” – lightedman
- “That was true years ago, but I haven't been able to use an iPhone camera to pick up an IR signal in a long time.” – happyopossum
- “IR is deliberately (though imperfectly) filtered in the optical path.” – ssl‑3
- “Try the selfie (aka front‑facing) camera; often they are not equipped with an IR filter.” – ThePowerOfFuet

3. Debate over the practical value and threat model
Opinions split on whether detecting hidden cameras is worthwhile, with some seeing it as essential for privacy and others deeming it unnecessary given more concealed surveillance options.
- “Detecting increasingly easy to conceal sousveillance devices is probably essential for any kind of normative public sphere to continue to exist.” – dbspin
- “For now, but there's really no point in detecting them anyway, since there are plenty of truly concealed options for those that really want to be pervs.” – stronglikedan
- “I'm an adult male so I don't care if someone wants to record my dong but this is very helpful for families with kids.” – expedition32
- “Perhaps to avoid tipping off the entity recording you by blasting their hidden cameras with bright lights.” – evilduck

🚀 Project Ideas

GlintScan: Smartphone Hidden Camera Detector App

Summary

  • Uses the phone's flash and camera to detect lens reflections and glints from hidden lenses, works even when the camera is off.
  • Core value: Quick, no‑extra‑hardware privacy scanning for travelers and renters.

Details

Key Value
Target Audience Travelers, Airbnb/hotel guests, privacy‑conscious consumers
Core Feature Real‑time reflection detection with ML filtering to reduce false positives; optional IR detection via front camera
Tech Stack React Native (or Flutter), OpenCV, TensorFlow Lite for on‑device model, phone flashlight APIs
Difficulty Medium
Monetization Hobby

Notes

  • HN users praised the flashlight trick: “salt_pine: Definitely trying this next time I check into an Airbnb.”
  • Community sentiment: “famahar: This is great. Hopefully this device becomes so ubiquitous that it deters anyone from putting up hidden cameras.”
  • Provides a practical, software‑only solution that addresses the demand for simple, on‑the‑go detection discussed in the thread.

MultiSensor Privacy Scanner (MSPS) – Keychain Device

Summary

  • Combines visible‑light reflection, IR emission/detection, and thermal scanning to spot hidden cameras across multiple modalities.
  • Core value: All‑in‑one portable tool that works even if cameras are powered off or use IR filters.

Details

Key Value
Target Audience Security professionals, privacy advocates, frequent travelers
Core Feature Scan button triggers flash pulse, IR LED array, and microbolometer thermal sensor; results shown via LED indicators or Bluetooth to phone app
Tech Stack ESP32 or STM32 MCU, IR LEDs, photodiode, MLX90640 thermal sensor, Bluetooth Low Energy, firmware in C/C++
Difficulty High
Monetization Revenue-ready: One‑time sale $49 per unit

Notes

  • Commenters noted thermal usefulness: “thimble_io: Wonder if it handles the really tiny pinholes effectively. For now, a thermal camera feels more robust for peace of mind.”
  • The device overcomes the limitation that thermal alone can’t detect off cameras: “akd: This detects cameras that are off, which a thermal camera would not.”
  • Combines several detection methods discussed (flash reflection, IR, thermal) into a single handheld tool, appealing to those seeking a robust privacy sweep.

CrowdScan – Community Hidden Camera Map Service

Summary

  • Aggregates anonymized scan results from users’ devices to build a public map of locations with suspected hidden cameras.
  • Core value: Empowers the community to warn each other and deter covert surveillance.

Details

Key Value
Target Audience Privacy‑conscious travelers, renters, advocacy groups
Core Feature Upload scan metadata (location, timestamp, detection confidence); server aggregates and displays heatmap; users receive alerts when entering flagged zones
Tech Stack Backend: Node.js/Python (FastAPI) + PostGIS; Frontend: React + Mapbox GL; Mobile SDK: React Native
Difficulty Medium
Monetization Revenue-ready: Subscription $4.99/mo for real‑time alerts (free basic access)

Notes- Users expressed a desire for shared knowledge: “famahar: This is great. Hopefully this device becomes so ubiquitous that it deters anyone from putting up hidden cameras.”- Speculation about prevalence: “apples_oranges: I would assume most Airbnbs have hidden cameras, but that’s just a feeling” indicates a need for community‑sourced data.

  • Provides a network effect solution that turns individual detection attempts into a collective safety resource, addressing the frustrations of unreliable solo checks.

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