Unclear Signifiers
The metallic horizontal bars that serve as buttons look like decorative trim. No visual cue communicates "press here." Icons above the bars — cup, steam, water droplet, "1" and "2" — have no text labels.
- Problem
- A visually minimal espresso machine with 4 usability failures — missing signifiers, ambiguous feedback, broken mental model, hidden interactions
- Approach
- Applied Norman's 6 design principles to map every failure point, then redesigned to preserve aesthetics while fixing the interaction model
- Result
- 6 violations resolved across 4 principles — first-time users can operate the machine without the manual
01 — Problem
Four Layers of Usability Failure
Through daily use and systematic analysis, I identified four interconnected issues that together create a consistent pattern of confusion:
Inconsistent Feedback
A blinking LED means "preheating" in one context but "phase complete, press to continue" in cleaning mode. The same signal carries different meanings with no differentiation.
Broken Mental Model
The button layout doesn't reflect the natural coffee-making sequence: grind → fill portafilter → power on → preheat → select strength → extract → steam. The interface creates cognitive mismatch.
Hidden Interactions
Temperature adjustment requires a long-press with zero indication on the interface itself. There are no error states for low water, no warning before the machine becomes unusable.
"They needed a way to designate which parts could be touched, slid upward, downward, or sideways, or tapped upon."
— Donald Norman, The Design of Everyday Things (2013), p. 34
02 — Process
Applying Norman's Framework Systematically
Rather than listing problems intuitively, I structured the analysis around six specific design principles to ensure each finding was grounded in established UX theory:
- Signifiers
- Flat bars look purely decorative — zero visual affordance for pressing without reading the manual first.
- Affordances
- No tactile cue invites physical interaction; the bars feel like trim, not controls.
- Feedback
- Same LED blink carries different meanings across brewing and cleaning contexts.
- Mapping
- Button placement ignores the natural coffee-making sequence — users can't intuit order from position.
- Conceptual Model
- Interface fails to represent the user's mental workflow; the gap causes systematic, repeatable errors.
- Constraints
- No error prevention for low water or improperly installed portafilter — dangerous states pass silently.
03 — Redesign
Solving Problems Without Losing Minimal Aesthetics
The redesign goal was specific: fix the interaction model, not the visual identity. The machine's clean aesthetic is a feature — the task is to make clarity and beauty coexist.
- Icons only, no text labels
- Temperature hidden in long-press
- Blinking LED = ambiguous meaning
- No audible feedback at all
- No low-water warning system
- Buttons not sequenced to workflow
- Icon + text label pairs on each button
- Dedicated visible temperature button
- Consistent LED: blink = in progress only
- 3 beeps (complete) / 2 beeps (warning)
- Blinking low-water indicator locks functions
- Layout follows brew sequence left-to-right
A shared Start/Stop button creates a clearer two-step mental model: select mode first, then initiate. This reduces accidental triggers and makes the system state always legible to the user.
View Live Prototype04 — Outcomes
What Changed and Why It Matters
- 6
- Usability violations identified
- 4
- Norman principles violated
- 6/6
- Resolved in redesign
-
01
Discoverability without a manual. Text labels alongside icons mean a first-time user can identify every control without any reference material.
-
02
Unambiguous system status. Consistent LED semantics (blinking = active process only) combined with distinct audio tones eliminate the feedback guessing game.
-
03
Error prevention over error recovery. The low-water lock prevents users from starting a brew that will fail mid-extraction — a common frustration point.
-
04
Workflow-aligned layout. Button sequence mirrors the cognitive model of making coffee, reducing the mental effort required to operate the machine correctly.
05 — Reflection