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509 points nullpxl | 1 comments | | HN request time: 0s | source

Hi! Recently smart-glasses with cameras like the Meta Ray-bans seem to be getting more popular. As does some people's desire to remove/cover up the recording indicator LED. I wanted to see if there's a way to detect when people are recording with these types of glasses, so a little bit ago I started working this project. I've hit a little bit of a wall though so I'm very much open to ideas!

I've written a bunch more on the link (+photos are there), but essentially this uses 2 fingerprinting approaches: - retro-reflectivity of the camera sensor by looking at IR reflections. mixed results here. - wireless traffic (primarily BLE, also looking into BTC and wifi)

For the latter, I'm currently just using an ESP32, and I can consistently detect when the Meta Raybans are 1) pairing, 2) first powered on, 3) (less consistently) when they're taken out of the charging case. When they do detect something, it plays a little jingle next to your ear.

Ideally I want to be able to detect them when they're in use, and not just at boot. I've come across the nRF52840, which seems like it can follow directed BLE traffic beyond the initial broadcast, but from my understanding it would still need to catch the first CONNECT_REQ event regardless. On the bluetooth classic side of things, all the hardware looks really expensive! Any ideas are appreciated. Thanks!

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sspiff ◴[] No.46076613[source]
I remember seeing some celebrities in the late 00s / early 10s with IR-emitting sunglasses or accessories to flood the camera sensors of paparazzi and make it harder for photographers to get spyshots of them.

Would this approach work for these camera glasses as well, simply flooding them with so much IR spectrum light that their sensors simply can't see you anymore?

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nullpxl ◴[] No.46076701[source]
One of my future ideas was to have the detection trigger turning a bunch of IR LEDs on to do just this! I've only tested it a little bit against my phone camera (with around 5 850nm LEDs), but it didn't work super well (fairly bright but not enough to be useful). It did work much better in low-light though. My guess is modern cameras have better IR-cut filters, but like I mentioned I only tested against my phone and not the Ray-bans yet.
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spacedoutman ◴[] No.46076779[source]
Have you thought about the potential eye/skin damage you would be causing with IR LEDS.
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card_zero ◴[] No.46076981{3}[source]
Potentially as much as none, because it's UV that does the damage?
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1. thih9 ◴[] No.46077024{4}[source]
I guess IR can be harmful (IR lasers, military grade IR LEDs). But yes, likely not the consumer grade IR LED.