How we engineered a brain tracker that looks like glasses

If there’s one part of the body that silently reveals what’s going on in the mind... It’s the eyes. Our eyes shift, jitter, pause, and blink in patterns that tell a detailed story about our attention: How focused we are, when we’re tired, or mentally drifting. In neuroscience and psychology, this isn’t new. There’s a reason people say the eyes are a window to the soul. And they’re also a window to the mind.

So we asked ourselves: What if there was a wearable that used the eyes to track the mind?

Why cognitive wearables don’t exist (yet)

First, let's understand why we don't see cognitive wearables today. The answer lies in a combination of form factor, signal quality, and comfort. We have wearables that track heart rate, steps, and sleep. But tracking the brain has always been more difficult, and often limited to:

• Clinical EEGs with bulky, rigid headgear

• Meditation bands that require forehead sensors

• Or smartwatches using heart rate variability as a loose proxy for attention (rare)

These approaches are either too invasive, too indirect, or too limited for most people to use meaningfully in everyday life. What’s missing is a way to sense cognitive state accurately, passively, and in a form people are already comfortable with.

Why glasses?

If you want to measure the brain without going through the skull, you have to get creative. Instead of building a headband or helmet, what if we embedded cognitive sensing into something people already wear, like glasses?

The frame of a pair of glasses sits in an ideal position to capture eye-related biosignals. More specifically, the skin around the eyes, the canthi (inner and outer corners), the infraorbital ridge beneath the eye, and the bridge of the nose carry clear biopotential signals related to eye movement. These signals are generated as the eye rotates in its socket, creating voltage shifts between the front and back of the eye. This is the foundation of electrooculography (EOG), a well-established technique in lab research used to track eye position, saccades, blinks, and visual attention patterns.

In other words, EOG is like turning your eye movements into a heart rate monitor for your attention. Whether you’re reading, scrolling, or staring into space, every movement creates an electrical signature on a graph. It peaks when you look left or right, flat lines when you stare. Over time, it shows whether you're focused or distracted.

By placing electrodes near the eye (say nose pads), we’re able to capture these signals passively, without altering the appearance or feel of the glasses. No forehead straps. No calibration rituals. Just wear and forget.

But getting those signals to a usable state isn't straightforward. And once we built our first prototypes, the reason this had never been done before became super obvious.

Noise is your enemy

We spent months iterating through different setups, each time trying to preserve signal fidelity while minimising noise, movement artefacts, and environmental interference. Our early versions used standard electrode wires without shielding, and while we could detect high-level signal events like large blinks or head movement, the finer, low-amplitude eye movements that matter most for attention tracking were lost in a sea of noise.

So we began refining every part of the analogue chain.

1. The first breakthrough came when we fully enclosed the electrode leads in copper shielding, isolating them from external electromagnetic interference. The kind that comes from powerline, microwave oven, and even your PC. Shielding alone made a clear difference, but wasn’t enough on its own.

2. Next, we verified and optimised grounding continuity across the entire device, from the electrode terminals to the PCB. Any floating ground or inconsistent shielding introduced subtle voltage instability, which was enough to distort the low-frequency signals we needed. We found that even minor inconsistencies in wire routing or placement would degrade performance.

3. Finally, and most importantly, we realised that many off-the-shelf biosensing systems are configured to suppress the 0-1Hz frequency range, which is the exact range where micro-saccades, gaze drift, and blink-recovery arcs appear. These systems are typically designed to filter out what they interpret as “baseline drift”, or simply to filter out direct current (0Hz). So we did some more painful stuff and customised our own analog front-end and PCB design to preserve 0.1-1Hz range, while still managing artefacts. That meant tuning capacitor values, adjusting gain, and balancing signal clarity against environmental robustness.

There's one more thing, but that's being patented - so we'll have to leave that one out for now...

The above together allowed us to capture subtle eye behaviours that are strongly correlated with real-world focus and attention patterns. Without access to these signals, any inference about attention would be incomplete or unreliable. But with them, we had something unique: a low-power, discreet, and relatively noise-resilient method of tracking focus through real-world eye behaviour, all embedded inside a pair of everyday glasses.

From signal to personalised insights

Once we stabilised the signal, the next challenge was to turn the eye movement data into something meaningful. Rather than trying to infer everything straight away, we decided to start by focusing on one thing: Flow.

Why flow?

Flow is the state of deep, effortless focus, when you’re fully engaged in what you’re doing and time seems to disappear. It’s not just desirable, it's essential for creativity and productivity. People rely on flow when being creative. People with ADHD find themselves able to hyper focus when they're "in flow". Freelancers, founders, and deep thinkers depend on flow to produce meaningful work in a world full of noise.

But flow has always been invisible. You might feel like you were “in flow” today, but can you see when it started? How long it lasted? What pulled you out? With Journey Frame, we’re building the first tool that makes flow measurable passively, through EOG.

Benefits of tracking flow

When you can see your focus, everything changes. Tracking flow helps you:

• Understand your best hours so you can protect them.

• Build better habits around work, rest, and recovery.

• Reduce time lost to distraction by recognising early signs of drift.

• Train your mind (like a muscle) to enter flow more easily, and stay there longer.

For founders, creatives, academics, and people navigating a world full of noise, this isn’t just useful. It’s foundational. Focus is our edge. Flow is how you sharpen it.

We’re launching soon

If you want to try it, support it, or help us take it further, now’s the time.

• If you’re an investor, advisor, founder or just curious, please reach out.

• Or share this with someone who should see it.

• Request for a pitch deck: contact@phantomtech.io

Thanks for reading - I hope you maintained flow.

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