Every recording device used to announce itself. A camera looked like a camera. A phone raised to face level meant a photo was coming. Smart glasses removed that cue. They look like ordinary eyewear, and they can capture the people around them with nothing to show that recording has started. The oldest agreement in public space, that you can see the lens pointed at you, quietly stopped holding.
NearLens was built to give that signal back. It scans for the Bluetooth signatures that smart glasses broadcast and tells you when a pair is nearby, so the awareness reaches you while you can still act on it.
There is a standard for building software this way. It is called Privacy by Design, and it was developed by Dr. Ann Cavoukian during her time as Information and Privacy Commissioner of Ontario. The idea is that privacy belongs in the architecture of a product from the first decision onward, rather than being added near the end as a policy or a checkbox. A product that asks people to consider who is watching should be able to answer the same question about its own conduct.
The framework has seven principles. Here is each one, and how NearLens holds to it.
Principle 01
Proactive, not reactive
The first principle asks a product to anticipate a privacy risk and prevent it, instead of supplying a remedy once the harm is done. Prevention is the entire premise of NearLens. It warns you that smart glasses are close before you are recorded, at the point where the information is still useful. A tool that told you about the recording afterward would only be a record of the loss. This one works while you still have a choice.
Principle 02
Privacy as the default
People should be protected without having to hunt through settings to arrange it. Protection is the resting state of the app, there before you touch anything. NearLens starts detecting the moment it opens, and detection is the whole of what it does. There is no separate privacy mode to switch on, because there is nothing else for the app to be.
Principle 03
Privacy embedded in the design
Cavoukian's third principle treats privacy as part of how a product is constructed, present in the engineering rather than layered on top of it. For NearLens this is close to literal. The reason the app has any screens at all is privacy, and the alerts, the interface, and the Bluetooth detection underneath them were designed around one act: surfacing a signal that would otherwise stay invisible.
Principle 04
Full functionality, positive-sum
An older way of thinking treated privacy and usefulness as a trade, where gaining one meant losing some of the other. The fourth principle refuses that trade and asks for both at once. NearLens does not buy your awareness with your data. What it gives you, knowing when a camera is present, does not arrive in exchange for handing over who you are. You end up with more than you started, without giving anything up.
Principle 05
End-to-end security across the lifecycle
Data should be protected for as long as it exists, from the moment it is created to the moment it is discarded. The most reliable version of that protection is to gather as little as possible in the first place, since information that is never collected cannot be leaked, sold, or subpoenaed. NearLens reads the Bluetooth Low Energy signals it needs on your own phone, where the detection happens. The less that leaves the device, the less there is to defend.
Principle 06
Visibility and transparency
A privacy system should be open to inspection rather than asking for blind faith. Cavoukian summed it up as "trust, but verify." NearLens carries this in its lineage. The app is open source, built on a project released under the AGPL 3.0 licence (github.com/yjeanrenaud/yj_nearbyglasses), which means the code can be read by anyone who wants to confirm what it actually does. A claim you can check for yourself is worth more than one delivered as a promise.
Principle 07
Respect for the user
The last principle keeps the person at the centre and puts their interests ahead of the system's convenience. This is the one the other six lean on. NearLens was built for the person standing in a room with no way to know that a lens is running. The detection, the data restraint, the design decisions all descend from that obligation.
Why this matters
Privacy in public has always rested on knowing. You could read a room, see the cameras in it, and adjust how you spoke and who you trusted with that knowledge in hand. Wearable recording takes the knowing away. When you cannot tell whether you are inside someone's footage, the decision about how to carry yourself in the world has already been made for you, by someone you cannot see.
One app does not undo that shift. What NearLens restores is a single piece of it, the awareness, and awareness is the ground that consent stands on. Because the project is open, and its field research is meant to reach privacy advocates and regulators, the effort reaches past the App Store into a wider argument about what people are owed in the places they share.
The honest part is that the devices are moving faster than the norms meant to hold them, and any detector will trail the next product to ship. That distance is the real problem, and no single app is going to close it. What this one can do is make the distance visible, and keep the question in front of the people with the power to answer it.