Why I'm building a hat that taps me on the head
I have retinitis pigmentosa — a genetic eye condition that’s been slowly closing in on my vision since my early teens. Night blindness came first, then the periphery started going. What’s left is tunnel vision: my central vision works, but everything at the edges is gone. On a hiking trail this creates a cruel little geometry problem. The ground is where most of the danger is — roots, rocks, steps — so my eyes stay down. But with no peripheral vision, looking down means everything above my eyeline stops existing. Branches, low signs, rock overhangs: I find them all the same way, forehead first. Being 6’2” makes me an even better branch-finder.
The idea was born a few years ago in Tafraoute, Morocco, hiking with friends through terrain made of giant boulders and head-height trees. My workaround then was the same as now: ask friends to call out obstacles, or scan up-down-up-down between the ground and the air until my neck and brain gave up. Somewhere in there I thought — what if the hat could just tell me? Then the idea did what ideas do, and sat in a drawer for a few years while life (and a burnout, and a move to rural Portugal) happened.
This year, still ducking branches on the trails here, it came back — and this time I researched it. Three things convinced me to actually build it: it’s genuinely buildable, cheaply; nothing like it exists on the market anymore; and the problem it solves isn’t just mine. Not navigation, not obstacle detection in general, just: tap me when something is about to hit my head, so I know to look up. My central vision handles the rest.
The idea
A baseball cap with a small distance sensor on the brim, aimed forward and slightly upward. When something enters the warning zone, a little motor against the sweatband vibrates — slow pulses when it’s far, rapid pulses as it gets close. Parking-sensor logic, for your head. Silent, so my ears stay free for the trail. No camera, no app, no subscription. The brains and battery ride in a pocket.
The key insight, which took me embarrassingly long to articulate: my eyes still work — the hat just has to tell me where to point them. Central vision does the classification and the dodging. The hat only covers the blind spot above my gaze.
What I found when I looked for existing products
I assumed something like this must exist. It sort of did — and mostly doesn’t anymore. The affordable wearables closest to this idea (the BuzzClip, the Sunu Band) are discontinued. What survives is either expensive ($850 smart canes, €9,999 AI glasses) or solves a different problem. And when I dug into why the dead products died, one pattern appeared over and over: false alarms. Devices that buzzed for phantom obstacles got tuned out, then left in drawers. Users forgive short range; they don’t forgive being lied to.
That finding now shapes the whole project. The research section has the full write-ups — the market scan, what real users said about these devices, and the sensor physics rabbit hole I fell down (did you know bright sunlight blinds most cheap laser distance sensors? I do now).
Where things stand
Parts for Prototype 1 are ordered — about €87 total, chosen so that nothing needs soldering. The prototype page has the full breakdown and the seven questions this build has to answer. The short version: desk tests first, then a comfort trial, then an indoor obstacle course of pool noodles and hanging towels, then a safe outdoor area with a sighted friend. Every test gets logged and published here, including the failures. Especially the failures — the documented failures of other devices were the most useful research material I found, so the least I can do is add mine to the pile.
Why “The Hat Project”?
Because it’s a project, and it’s a hat. I went through about 150 name candidates (Periphery! Blindside! The Whisker Project!) before realising the plain one was the one I kept saying out loud.
This is a side project. There’s no deadline, no Kickstarter, no pressure — the site just grows as the project does. If you have RP or low vision, if you’ve built something similar, if you know sensors or firmware, or if you just have thoughts: email me. I’d love to hear from you.