UNIVERSITY OF MARYLAND BALTIMORE COUNTY

Cold Mode: making smartphones usable in freezing weather
A system-level mode that adapts touch targets, contrast and feedback for people using their phones in sub-zero temperatures, often with gloves on.
TIMELINE
Sep – Dec 2025
ROLE
UX Designer & Researcher
TEAM
Two designers: Aasmita Bhattacharya and me
CATEGORY
Mobile accessibility, interaction design
ON THIS PAGE
Overview
At a glance
Problem
Key decisions
Process
Solution
Learnings
OVERVIEW
Smartphone interfaces assume warm hands and precise taps. Below 0°F (−18°C), neither holds: gloves block or blur touch input, and cold fingers lose dexterity within minutes. Aasmita Bhattacharya and I designed Cold Mode, a setting people switch on when they head outside, much like airplane mode. It enlarges touch targets, strengthens contrast and haptic feedback, and keeps the phone usable from the lock screen onward without removing gloves. The work covers research, interaction design, a low-fidelity prototype and a usability study protocol. The study hasn't been run yet, so this case study focuses on the design and the reasoning behind it rather than measured outcomes.
AT A GLANCE
12 mm
Minimum touch target size across Cold Mode, including the keyboard
14–16 mm
Passcode key size, so people can unlock with gloves on
0°F
Test condition defined in our usability study protocol
Why phones fail in the cold
Cold affects the hands, not the intent
Research by Sarsenbayeva et al. showed that short exposure to cold reduces fine motor control in the fingers, while attention stays largely intact.
In practice, someone waiting for a bus in January knows exactly what they need to do on their phone but can't do it reliably. The usual workarounds each fall short: conductive gloves register a touch but are still too coarse for small targets, a stylus is one more thing to carry and drop, and voice input struggles with wind and background noise. The operating system doesn't help much either, since touch sensitivity settings are buried and the layout itself never changes. When we traced the full journey, one gap stood out above the rest: the problem starts at the lock screen. If someone can't enter a passcode with gloves on, every improvement after that point is out of reach.
Three decisions that shaped Cold Mode
01
Manual control over automatic adaptation
We made Cold Mode something people turn on themselves rather than something the phone triggers from sensor data. Findlater and McGrenere found that users preferred interfaces they could adapt over ones that changed on their own, and a layout that rearranges itself unexpectedly is hard to trust, especially when someone is already struggling to use it.
02
Access starts at the lock screen
Our first concept placed the toggle in quick settings, which still required unlocking the phone. We moved it onto the lock screen, added a double-press of the power button as a no-look shortcut, and enlarged the passcode keys to 14–16 mm with a wider touch tolerance.
03
Fewer, larger targets and simpler gestures
Every target in Cold Mode is at least 12 mm, informed by Fitts's Law and prior work on input with reduced motor control. Non-essential elements are hidden, frequent actions sit within thumb reach at the bottom of the screen, and gestures like long-press and swipe-to-confirm are replaced with single taps.
How the design took shape
01
Defining the problem space
We started from situational impairments, temporary limitations caused by the environment rather than by the person, and focused on extreme cold, where gloves and stiff fingers compound each other.
02
Reviewing research on cold and touch
Studies on cold exposure pointed to one clear priority: adapt the physical interaction first, through target size and input tolerance, before adding anything new to the interface.
03
Mapping the context with HAAT
Using the Human, Activity, Assistive Technology model, we mapped who is affected, what they need to do and where. It confirmed that the solution should be software already on the phone, not another accessory to buy and carry.
04
Exploring an essentials-only home screen
Our first concept reduced the home screen to five essentials (call, camera, maps, payment and an emergency contact), added stronger haptic feedback and limited input to taps.
05
Grounding decisions in prior work
We tied each design choice to existing research: manual control, target sizing for impaired motor input, high contrast for glare, and RainCheck as evidence that phones can adapt to environmental conditions.
06
Closing the lock-screen gap
Walking through the end-to-end journey exposed the unlock step as the real barrier. We redesigned entry into Cold Mode, specified sizes for every target, sketched the four core screens and wrote the usability study protocol.
From locked phone to sent message
Four core screens, designed for gloved hands
The prototype covers the moment that matters most outdoors: getting from a locked phone to a call, a message or an emergency contact without taking gloves off.
Cold Mode turns on from a snowflake button on the lock screen or a double-press of the power button, and a stronger vibration plus a status badge confirm the change. The passcode keypad expands, the home screen reduces to search, a dedicated SOS tile and six large app tiles, and the keyboard spreads its keys further apart. Contrast exceeds WCAG 2.1 AA so content stays readable against snow glare.
Lock-screen access
Turn Cold Mode on from the lock screen or with a double-press of the power button, with no unlock required.
Glove-friendly passcode
Keys of 14–16 mm with a wider touch tolerance, so near misses still register.
Emergency access first
A dedicated SOS tile sits above everything else on the home screen.
Stronger haptic feedback
Firmer vibration patterns, because gloves absorb the subtle feedback phones normally rely on.
Takeaways
Map the full journey before designing screens
Much of our early effort went into refining the home screen before we realized that gloved users are blocked one step earlier, at the passcode. Tracing the journey end to end, from pocket to completed task, would have surfaced that sooner, and it's now where I start on a new problem.
A strong rationale is not a validated result
Every decision in Cold Mode is grounded in published research, but it hasn't been tested with people in real cold yet. The next step is running the chamber study we designed, then moving to field testing with a wider range of gloves.
Areas of Improvements
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Want the full story?
The screens shown here are redrawn from our original sketches. I'd be glad to walk you through the research, the trade-offs behind each decision and how I'd approach testing it.
itsmehersunitha@gmail.com
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