TrailMate

Solo hiking is often avoided out of fear of harassment, injury, or getting lost — a barrier that falls disproportionately on women and other minority groups. TrailMate is a two-way bracelet system, one for the hiker and one for a trusted partner at home, that keeps both sides quietly aware of each other and lets either one raise an alert.

From social sports to solo hiking

Early concept sketches

Mind-mapping social sports narrowed the focus to hiking, then to women and minorities who hike solo. Ideas came from 6-3-5 brainwriting — three sketches per member, voted on by the group.

The two top ideas — a check-in bracelet and a health-status ring — were merged into one bracelet system, chosen for comfort and clearer colour visibility while hiking.

Tape, paper and string first

A low-fidelity prototype came first: two bracelets built from tape, paper, string and pearls, one for the hiker and one for the partner, the partner's bracelet operated with a Wizard-of-Oz technique — pulling different coloured paper through it to simulate status changes. Two semi-structured interviews (three women, one man, ages 20–30) tested the concept against a written hiking scenario.

Feedback reshaped the design for the working prototype: the two separate bracelets were merged into a single unit, the emergency self-indication tag was dropped in favour of a simpler interface, and a new "warning" mode was added for situations between a routine check-in and full distress. The feedback system was expanded to auditory, haptic and visual signals together, and GPS coordinates are sent as an SMS rather than only shown on the bracelet.

The working prototype ran on an Arduino Uno with a button and an LED strip cycling white, green, yellow and red. The band was hand-sewn from fabric sized to hold the LED strip, button and wiring; the links covering the LED strip were modelled in Fusion 360 and 3D printed in transparent PLA, designed to click together and rotate independently so the band could wrap the wrist.

Figure 2 — Low-fidelity prototype, tape and string

Figure 3 — Building the LED and button circuit

Four states, two bracelets

Figure 4 — Interaction and feedback table for hiker and partner bracelets

Figure 5 — The four status states: idle, confirmation, warning, distress

Idle — white

Default state, nothing pending

Confirmation — green

Both bracelets flash green once a check-in is answered, then return to idle

Warning — yellow

The hiker flags a possible risk before it becomes an emergency — the partner's bracelet turns yellow, the hiker's blinks and vibrates once

Distress — red

Triggered by holding the button for three seconds — vibrates, sounds, and sends the hiker's GPS coordinates to the partner by SMS

Figure 6 — (a) The idle state of a hikers' smart bracelet

Figure 7 — (b) The connected partner bracelet

Figure 8 — Hikers bracelet in hike-mode

Figure 9 — Partner bracelet in home-mode

What the pilot interviews changed

Both changes came directly out of the pilot interviews.

Sound, touch and light together

The feedback system was refined to combine auditory, haptic and visual signals so no single channel carried the whole message and people with disabilities weren't excluded. GPS coordinates are sent as an SMS text message rather than shown only on a small screen, since phones can read texts aloud for people who are visually impaired.