Trails can get busy, and others stay empty, but how do you know? We built Trailsense to answer that. Our solar-powered nodes count hikers using anonymized wifi probe requests, the pings a phone sends while scanning for known networks. A dashboard turns those counts into a clear view of how busy each trail is over time. No cameras, no app for hikers to install, and no personal data ever leaving the device.
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Hey, I'm Francesco, one of three people behind Trailsense, along with Felix and Lea.
We build small solar-powered sensor nodes that count how many people pass by on a hiking trail, without cameras and without hikers having to install anything. The nodes listen for wifi probe requests, the background pings a phone sends out while scanning for known networks, and turn them into an aggregated count. No raw probe request data ever leaves the node, and no personal data is stored anywhere in the system.
The idea started at the Tourism Technology Hackathon in 2025, where Tirol Werbung brought us a real problem: they know exactly how many people sleep in which hotel each night, but almost nothing about where those people go during the day. We kept working on it as our master's project, and this year we ran a pilot on the Nordkette in Innsbruck alongside Tirol Werbung.
Right now Trailsense is pre-commercial. The pilot is done, we're refining the dashboard and the node hardware, and we don't have a public demo up yet since it's still a bit rough around the edges. Longer term we want to add a public-facing side too, something like Google Maps traffic data but for hiking trails, so hikers can check how busy a trail is before heading out. For now our focus is the municipality and tourism board side.
We're posting here mainly to get feedback, whether you've built sensor hardware yourself or you're just someone who hikes and has opinions about being tracked outdoors. What would make you trust a system like this to collect data around you? And if you were a hiker using a public facing traffic-map version someday, what would you actually want to see on it?
Our node firmware is open source on GitHub (github.com/trailsense) if you want to see exactly how the data collection works.
Happy to answer any questions.
clever way to get a busyness signal without cameras or an app install. one thing i'm curious about given how the tech works - modern phones (iOS and most recent android) randomize their MAC address per probe request specifically to prevent exactly this kind of passive counting. does trailsense do any signal-strength/timing clustering to guess that five different randomized addresses over an hour are probably the same phone, or is the count more of a relative busyness proxy (more pings = busier trail) rather than an actual hiker headcount? asking because the accuracy story is pretty different depending on which one it is.
Hey @galdayan, thank you a lot for your comment!
Yea MAC address randomization was a bit of a struggle for us, but luckily we found a good paper that describes a method using pre-trained “filters/bit-masks”. Using these you create a fingerprint for each probe request, and then compare those fingerprints to each other. Based on how “similar” the fingerprints are you can either count them as one device or as two distinct ones. Of course it will never be 100% accurate, but with the data from the pilot project we want to improve the nodes in general and refine the fingerprinting.
At the end the idea is to have a trend or estimate of hikers, since we cannot guarantee an exact count due to the inherent inaccuracy. Also, someone might not be carrying a phone at all, or could have a second device like a smart watch with them.
Took a look at the dashboard and the wifi probe approach is clever - feels like the trailhead counts line up with what I'd expect on a busy weekend. Nice that nothing leaves the device.
Thanks @caferkalnursr! Glad you like the privacy aspect, it's fundamental to what we want to do.
The no-app approach is clever and the wifi probe trick actually makes sense after reading about it. The dashboard view over time looks like the kind of thing I'd check before a weekend hike.
Thank you very much @irmakbyktgjq! It’s great to hear that you are interested in the public trail-traffic part of the project.
Finally launching TrailSense today!
I really enjoyed working on a product that includes hardware. It was my first time being involved in something like that, and it made the whole project especially exciting.
Also here for any questions about our product :)