UX Research • Accessibility • Security Systems

OneButton PIN

OneButton PIN started from a broader question than “how do we improve a keypad?” The real question was: what interaction model makes authentication more accessible for blind and low-vision users while also reducing observational risk?

Instead of asking users to locate and tap digits on a visual keypad, this concept replaces spatial selection with a single haptic interaction target. Users press, feel pulses, count, and release. That shift reduces motor complexity, creates a more privacy-aware interaction, and opens a different security posture than the traditional keypad.

The work was recognized with the Best Paper Award at MobileHCI 2022, which matters here not just as recognition, but as evidence that the concept and the research design held up to serious scrutiny.

🏆 Best Paper Award · MobileHCI 2022 ♿ Accessibility-first authentication research

Haptic interaction model Privacy-aware authentication Shoulder-surfing resistance Research-led concept design

Survey research Diary study Prototype design Security evaluation Comparative testing Mixed-method synthesis

My role

Problem framing, concept development, interaction design, study structure, and synthesis into a product-relevant research narrative.

Research scope

Accessibility, authentication, haptics, privacy, and observational security treated as one connected system problem.

Why it matters

Shows how strategic research can surface an entirely different product direction before teams over-invest in optimizing the wrong interaction model.

Recognition

Best Paper

What this project demonstrates

This project stands out because it reframes the problem before solving it. It balances human needs, system constraints, and attack models, then validates the concept through evidence rather than novelty alone.

Survey

88 responses

Captured authentication behaviors, pain points, and privacy concerns for blind and low-vision users.

Diary study

9 participants

A week-long longitudinal study focused on learnability, repeated use, and accessibility over time.

Security study

10 observers

Tested whether reduced movement and timing variability made shoulder surfing materially harder.

Recognition

Best Paper

Awarded at MobileHCI 2022 for originality, rigor, and contribution to the field.

The problem

Traditional PIN entry assumes visual targeting, stable spatial orientation, and low observational risk. Those assumptions break down quickly for blind and low-vision users. Small tap targets are harder to use, audio feedback can leak sensitive information, and finger movement across a keypad creates visible patterns that bystanders can exploit.

The strategic reframe

Rather than polishing the keypad, I widened the problem space. The design challenge became: how do we reduce motor friction, preserve privacy, and change the attacker’s job at the same time? That reframe made a radically different interaction model possible.

Interactive simulator

This simplified simulator helps explain the interaction model. Press and hold the button, feel or see pulses, count them, then release to enter a digit. It is not the study prototype, but it makes the core mechanic tangible.

OneButton PIN demo

Checking vibration support…

— — — —

HOLD FOR PIN Hold to feel pulses → release to enter digit

Live count while holding0

Digit entered on release0

ModeOBP

Experimental controls

Vibration Interval (VI) 1000 ms

Time between pulses. In the paper, timing was part of the security design space, not just a comfort setting.

Vibration Duration (VD) 60 ms

Length of each haptic pulse.

Start Time (ST) 120 ms

Delay before the first pulse after press.

Randomize ST (0–200ms) Adds timing variability to reduce inference by observers.

Randomly increase VI (0–200ms) Simulates more unpredictable timing conditions explored in the evaluation.

Note: browser vibration support is inconsistent, especially on iPhone. This demo uses visual pulsing and subtle audio feedback when hardware haptics are unavailable.

Concept and interaction model

OneButton PIN replaces spatial digit selection with a single large interaction target. A user presses and holds, feels haptic pulses, counts them, and releases to enter a number. The design intentionally treats timing as part of the interaction and part of the security strategy.

Interaction shift

Removes the need to locate digits on a keypad.
Converts authentication into a count-and-release model.
Reduces dependence on precise motor targeting.

Security shift

Reduces visible movement patterns observers typically rely on.
Allows timing variability to make inference harder.
Changes the attack surface instead of only adding UI friction.

OneButton PIN concept image — **Concept model.** The interface reframes authentication around one large target rather than multiple visual keys, reducing motor complexity and creating a more controlled feedback loop.

OneButton PIN screenshots — **Prototype states.** These screens show how the concept was made concrete enough to evaluate as an actual interaction system rather than a speculative idea.

OneButton PIN interaction figure — **Interaction flow.** Press, count, and release becomes the central mechanic, replacing spatial search with a simpler repeatable pattern.

OneButton PIN interaction parameters — **Timing as design material.** Start time, interval, and duration were treated as meaningful design variables because they affect both usability and attack resistance.

Study structure

The evaluation was designed to answer a practical product question: is this concept learnable enough, usable enough, and secure enough to justify further investment? That meant using multiple studies instead of relying on a single positive signal.

Survey and discovery

Mapped current authentication habits and pain points.
Captured privacy concerns in public and semi-public environments.
Grounded the concept in real accessibility needs before prototyping.

Diary study and security testing

Tracked learnability and repeated use over a full week.
Compared multiple timing conditions, not just one ideal state.
Evaluated whether observers could infer entered digits.

Survey results figure — **Survey findings.** Early discovery helped establish the accessibility and privacy issues that made a different interaction model worth pursuing.

Additional survey results figure — **Research grounding.** The concept did not begin as a novelty exercise; it was grounded in user-reported friction, behavior, and context.

**Security study setup.** Observers were used to test whether OneButton PIN genuinely changed the shoulder-surfing problem instead of simply feeling more private.

Security study results — **Security study outcomes.** This is where the project becomes decision-relevant: the evaluation tests whether the concept materially changes observational risk.

What the results show

The results tell a nuanced story. OneButton PIN is compelling not because every metric is universally better, but because it demonstrates a viable alternative interaction model with real accessibility promise and meaningful security implications.

What worked

Participants could learn and use the concept over time.
The interaction reduced reliance on precise visual targeting.
The security evaluation showed promise against shoulder surfing.

What matters strategically

The concept clarifies where accessibility and privacy align.
Timing is a meaningful design lever, not incidental polish.
The output is a direction to refine, not just a one-off prototype.

Study 1 results — **Diary study results.** These findings show how the concept performed across week-long use, making the case stronger than a single-session lab result.

Study 1 additional results — **Comparative results.** Multiple timing conditions help show where tradeoffs appear, instead of overstating one idealized configuration.

Study 1 black and white results — **Performance patterns.** The data makes visible where usability gains and complexity costs shift across conditions.

Study 1 black and white additional results — **Signal over novelty.** This work earns credibility because the concept is tested from several angles instead of being presented as intuitively good.

Security study black and white results — **Security evidence.** This reinforces the key contribution: fewer visible movement cues can produce a different attack profile than a conventional keypad.

Security study result figure color — **Decision value.** The concept is strong because it helps teams reason about a credible alternative, not because it claims to replace every form of PIN entry.

Why this project stands out

What makes this project notable is not just the award. It is the combination of problem reframing, system-level thinking, and evidence-based decision support. The outcome is not simply a prototype. It is a strategic argument for a different product direction, supported by research.

Framing strength

The project questions the default keypad assumption itself.
It broadens the problem from UI friction to accessibility, privacy, and attack resistance.
It finds leverage in the interaction model, not just the interface layer.

Research strength

Uses survey, diary study, and security testing together.
Surfaces tradeoffs instead of forcing a simplistic conclusion.
Produces a direction teams could refine and ship responsibly.

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