User Experience & Accessibility Checklist

This checklist is prepared to evaluate product's physical and digital interaction with user, improve usability, and provide accessible experience for different user profiles. The goal is to develop a product that is intuitive as well as functional, accessible as well as aesthetic.

User-Centered Design Process​

1. Is target user profile (persona) defined?​

Before starting design process, who the product is developed for should be clearly defined.

User profile (persona) should be determined according to following criteria:

• Age range and physical characteristics
• Profession or purpose of use
• Technical knowledge level
• Usage environment (home, laboratory, field, factory, outdoor)
• Frequency and duration of use

This information directly affects all decisions from product sizing to interface design. Persona definitions should be created at project start and kept up to date throughout product lifecycle.

2. Are user scenarios (use cases) created?​

Typical usage scenarios (use cases) should be determined for each persona.

These scenarios should include:

• Normal usage flow
• Exceptional situations (error, interruption, power loss)
• Maintenance and installation processes

Scenarios are the foundation for testing both functional integrity and real-world behavior of product. Use case documents should be used as reference in Design Validation phase.

3. Are ergonomics studies conducted (size, weight, grip, button spacing)?​

Product's physical design should be evaluated according to ergonomic measurements and human factors engineering principles.

This evaluation should cover following elements:

• Product size and weight
• Grip, hold or mounting position
• Button, knob or screen spacing
• Visual access angles and readability
• Repetitive movement or muscle fatigue that may occur during use

Design should be analyzed ergonomically according to ISO 9241, IEC 62366 and ISO 6385 standards. Ergonomic tests should be supported both on prototype and with 3D digital simulation.

4. Is user feedback (interview, survey) obtained before design?​

Before design starts, interviews, surveys or field observations should be conducted with potential users. This process enables understanding users' real needs, expectations and usage habits.

For example:

• In which environment does user use device?
• Which feature of product does user need most?
• What errors or difficulties does user experience during use?

This feedback should be directly reflected in product's "design brief" document and design goals should be determined accordingly. User insights obtained at early stage prevent expensive design changes to be made in later revisions.

5. Are usability tests conducted on prototypes after design?​

After design is completed, user tests should be conducted on prototypes or early production samples.

Basic metrics observed in these tests are:

• Ease of use and learning curve
• Error rate and recovery times
• Button, screen or interface responsiveness
• Adequacy of visual/auditory feedback
• User satisfaction (subjective score)

Test results should be documented in Usability Test Report format and design action corresponding to each finding should be defined. This approach is foundation for continuously refining product with real user experience.

Visual and Physical Feedback​

6. Is product status communicated clearly to user?​

Product should communicate its current status to user in instant, clear and consistent manner while operating. These status indicators can be presented through LED, audible warning or screen notification.

Basic status examples:

• Active (ON) – system is running
• Error – operation stopped or failure occurred
• Charging – energy reception continues
• Standby – low power or ready standby mode

Status indicators should be positioned on product's front face, in user's viewing angle, and in directly understandable manner. Lack of feedback reduces user's confidence in product and increases service requests.

7. Are colors meaningful and consistent?​

Colors used in all visual indicators (LED, screen, icon, warning label) should comply with universal meanings and industry standards:

• Red: Error / emergency
• Green: Normal operation
• Yellow / Orange: Warning / attention
• Blue: Communication / connection status
• White: Neutral information or lighting

Color usage should be consistent throughout system; "red warning" in one unit should not be used as "charge indicator" in another unit. This standard reduces user learning time and increases product's intuitive usability.

8. Are status LEDs positioned according to user viewing angle?​

LED indicators should be placed considering device's typical usage position and viewing angle.

• Desktop products: top or front panel preferred
• Portable products: top edge or sloped surfaces recommended
• Industrial devices: should be positioned to be visible from distance

LED brightness level should be sufficient according to ambient light but should not be at dazzling level. Optionally, light diffuser or semi-transparent lens can be used.

9. Is audible feedback level adjustable or is mute mode available?​

Product's audible warning mechanisms (buzzer, speaker, click sound etc.) should be adjustable by user. User should be able to use product in different environments (quiet office, factory, open area) without causing discomfort. Mute mode or low volume option should be provided. Frequency, duration and interval values of audible feedback should inform user but not cause stress.

10. Is vibration / haptic feedback (if required) at appropriate intensity?​

In portable or touch interaction products, vibration (haptic) feedback should physically convey system response to user. Vibration intensity should be optimized according to device's weight, usage duration and environmental conditions. Too weak vibration is not noticed; excessive vibration creates user discomfort.

Example: Short (50–150 ms) pulses in 150–250 Hz range are generally optimally perceived.

11. Are visual icons or signs that guide user understandable?​

All visual signs (icon, arrow, symbol, warning label) should be compliant with universal graphic language and understandable without requiring text.

Example:

• Power button → "⏻"
• Bluetooth → "🔷"
• Charging → "⚡"
• Warning → "⚠️"

Iconography should be used with consistent scale and line thickness on all product surfaces and digital interface. Confusing or overly abstract icons can lead to user errors. Icon meanings should also be explained in user manual.

12. Are there tactile differences on product surface?​

Physical elements in user interface (button, knob) should be designed in tactile distinguishable manner.

For example:

• Power button can be distinctly raised or recessed from others
• Emergency stop button should be red and larger
• Frequently used controls should be placed on natural movement line of user's hand

These differences guarantee correct interaction even in dark environment or when using gloves. Tactile feedback is as effective on user confidence as visual design.

Accessibility and Inclusivity​

13. Is product accessible to different user groups (elderly, visually or hearing impaired, limited hand dexterity)?​

Product design should be evaluated to include users with different physical or sensory abilities. This is foundation of universal design approach.

Example applications:

• Raised icons or voice guidance for visually impaired
• LED warnings or vibration notification for hearing impaired
• Large buttons and low-force switches for users with limited hand dexterity

Accessibility tests should be conducted during design process and feedback should be included in ergonomics reports. Reference: EN 301 549, WCAG 2.1, ISO 9241-210.

14. Are high-contrast interface or color-blind friendly modes evaluated?​

Color contrast ratio in interface design should be at least 4.5:1. Screens containing critical information should be tested with "high contrast mode" or color-blind friendly alternative palettes.

Example:

• Blue-orange can be used instead of green-red combination
• Background and text color should create sufficient difference

15. Are critical functions expressed not only by color but also with icon or text?​

Warning or status information communicated to user should not rely solely on color. Each critical information should also be supported with icon, text or shape.

For example: "Red LED" + "⚠️" icon + "ERROR" text combination.

This approach increases accessibility for users with limited or color-blind color perception. Additionally, it strengthens product's understandability in different lighting conditions.

16. Do physical buttons have sufficient spacing (12 mm or more center to center)?​

Button spacing should be at least 12 mm center to center in accordance with human finger anatomy. This distance reduces risk of wrong button press and provides comfort when using gloves. Wider spacing (14–16 mm) should be preferred between frequently used buttons.

17. Is pressing force and feedback of buttons compliant with ergonomic values (60–100 gF)?​

Pressing force, tactile feedback (click feel) and travel distance of physical buttons should be appropriate for user comfort.

• Average force: 60–100 gF (approximately 0.6–1 N)
• Travel: 0.5–1.5 mm

Too hard buttons create fatigue during long-term use, while too soft buttons can cause uncontrolled pressing errors. Button mechanisms should be evaluated for 100,000+ cycle life in tests.

18. Are connection ports (USB, power input, audio, data) easily accessible and directions intuitive?​

All connection ports should be in positions that can be easily found and accessed by user. Port directions should be compatible with natural plug-unplug movement (e.g., vertical access instead of horizontal). Frequently used ports (USB, charging, data) should not be hidden on back or bottom of product. Minimum 10 mm clearance should be left around port to provide physical access ease. Connection directions should be supported with visual signs or raised icons.

19. Is product designed to be usable with one hand or while wearing gloves?​

User should be able to use all basic functions of device with one hand or while wearing gloves. This is especially important in field, industrial or outdoor applications. Button, joystick or screen positions should be within thumb reach limits. Support for glove mode is recommended on touchscreen products. These ergonomic scenarios should be practically verified in user tests.

20. Is screen or interface brightness readable in different ambient lighting conditions?​

Screens should be comfortably readable both in bright sunlight and low-light environments. Screen brightness should typically be in 400–800 nit range, contrast ratio should be 1000:1 or higher. Automatic brightness adjustment (ambient light sensor) or manual brightness control should be provided. Anti-glare surface coatings and high-contrast theme design should be preferred.

21. Are critical warnings communicated with audible + visual combination?​

All critical system warnings (e.g., error, battery low, connection lost) should be communicated to user through at least two different channels:

• Visual: LED, screen, icon
• Audible: warning tone or alarm
• (optional) Vibration: haptic feedback

This multi-notification approach ensures that users with different sensory limitations can also perceive warnings. Additionally, it increases safety by reducing human perception time in emergency scenarios.

Digital Interface and Interaction (If Applicable)​

22. Is user interface (UI) language clear, simple and free from technical jargon?​

Interface language should be simplified according to target audience's technical knowledge level. Texts should be short, direct and understandable; technical terms should only be used when necessary.

Example:

• ❌ "Wi-Fi connection error, DHCP timeout."
• ✅ "Connection failed. Please check Wi-Fi settings."

Language of texts should be friendly, instructive and encourage user to solution-focused behavior instead of stress. All texts used in interface should be reviewed according to "microcopy" standard.

23. Are interface elements consistent (icon style, font, color palette)?​

Iconography, font family, size ratios and color palette should be consistent in all pages or screens of interface. Consistency gives user sense of confidence and reduces learning time.

Following standards should be defined in design guide:

• Primary colors and accent colors
• Font family (e.g., "Roboto", "Open Sans")
• Icon set (e.g., "Material Icons", "Feather")
• Button shapes (radius, border, shadow)

All these rules should be defined in UI style guide or Design System document.

24. Does menu structure provide access to main functions with maximum three clicks / touches?​

User should be able to reach basic functions in maximum three steps (Three-Click Rule). Excessively deep menus cause user to lose direction and increase error rate. Menu layout should be prioritized according to frequency of function usage. Critical operations (e.g., data recording, power control, connection status) should be in first level menu. UI flow should be optimized by testing on "User Flow Diagram".

25. Are explanatory messages shown to user for erroneous operations?​

Each erroneous operation should present user with solution-focused explanation message, not just error code.

Example: "Connection failed. Please check Wi-Fi or try again."

Additionally, error screens should have action buttons (call to action) such as "Retry", "Open Settings". Error messages should not blame user, should guide. This approach is known as "empathy-first communication" in UX writing.

26. Are user settings (e.g., brightness, volume, connection preferences) saved?​

All personal settings made by user should be stored in non-volatile memory or within user profile.

For example:

• Brightness, volume level
• Wi-Fi / Bluetooth preferences
• Language selection or theme mode (dark/light)

These settings should be automatically restored when software restarts. This provides continuity in user experience and strengthens "personal" perception of device.

27. Is mobile application or web interface working synchronized with product (OTA, status sync)?​

Mobile or web-based applications should provide real-time synchronization (status sync) with product.

• Status information (online/offline, battery level, error status) should be reflected without delay
• OTA (Over-The-Air) software update system should be compatible with both device and application versions
• User should be given clear information in case of synchronization errors: "Device connection lost. Please reconnect."

Security of this integration should be ensured with TLS/SSL or similar encryption protocols.

28. Is application performance measured (with response time target shorter than 300 ms)?​

Response time given to user interaction should not exceed 300 milliseconds. This duration is limit of "instant response" in human perception. Delays should be explained to user with animation, loading bar or progress indicator. Performance measurements should be regularly tracked with telemetry logs or profiling tools (e.g., Firebase Performance, Perfetto, Tracealyzer). "UX Performance Benchmark" report should be created in each new version.

29. Are data privacy (Privacy Policy) and permission management clearly presented to user?​

Mobile or web application accompanying product should present user with clear privacy notice (Privacy Policy) about data processing procedures. User should easily see what data is collected, why and how long it is stored.

Additionally:

• Permissions such as microphone, location, sensor should be clearly requested
• Permissions should be revocable
• Data should only be transmitted through approved channels

Physical Safety and Usage Comfort​

30. Are corners, edges and surfaces safely rounded (radius larger than 1 mm)?​

All edges, corners and surface transitions of product that may contact user should be rounded with minimum R1 mm radius. This measure prevents injury, cutting or impact-related damage.

Deburring and edge rounding processes should be applied to metal or plastic parts after injection. To maintain balance between aesthetic design and safety, surface transitions should be verified with both visual and tactile tests.

31. Is temperature on user contact surfaces below 45°C limit (IEC 60950 standard)?​

Surfaces touched by user (e.g., cases, buttons, metal covers) should be below 45°C during operation.

This limit is specified in IEC 60950 / IEC 62368-1 safety standards. In areas exposed to higher temperatures (e.g., power regulators or motors), thermal insulation, air duct or heat barrier should be applied. Critical surface temperatures should be measured with thermal camera or sensor and added to prototype test reports.

32. Does product surface have texture that prevents hand slipping (matte, soft-touch etc.)?​

Surfaces in frequent contact with user (e.g., grip area, handle, button surroundings) should use non-slip surface texture.

Matte, soft-touch, micro-patterned or rubber coating surfaces provide secure grip even in case of sweaty hand or oily contact. Surface coatings should pass both chemical resistance and abrasion tests (ASTM D4060, ISO 2409). Excessively shiny or smooth surfaces can cause both glare and slipping during use.

33. Is center of gravity balanced in portable products, is there no tipping risk?​

In portable or handheld products, center of gravity should be balanced according to holding position.

Heavy components (battery, transformer, metal chassis) should be positioned at bottom region or close to balance axis as much as possible. Product should be tested for tipping tendency when standing upright (10° tilt test). Unbalanced weight distribution can lead to wrist fatigue or device drop risk during long-term use.

34. Is cable routing and cable length appropriate for user comfort?​

Cable exit direction, length and flexibility should be ergonomically designed for user to use device comfortably.

Cable directions should be determined according to typical usage position of device; for example, routing to back is preferred for desktop devices, to side for portables. Excessively short cables create pulling strain, while excessively long cables create tangling and breaking risk. Cable flexibility should be designed according to minimum bend radius rule and supported with strain-relief elements.

35. Are there no sharp edges or exposed conductive parts that could harm user?​

There should be no sharp metal/plastic edge, bare solder, conductive pin or area carrying high voltage on product's outer surface or accessible areas.

All open surfaces should be covered with insulation material or protective coating.

This control is especially valid for:

• Power inputs
• USB/charging ports
• Test pins
• Mechanical mounting areas

User Training and Experience Continuity​

36. Is user manual simple, illustrated and progressing step by step?​

User manual should be prepared as instructive guide rather than technical document.

Texts should be short, clear and appropriate to user language; complex sentences and technical jargon should be avoided. Each step should progress in numbered sequence and each section should contain visuals, icons or diagrams.

Example: "1️⃣ Plug in adapter → 2️⃣ Press power button → 3️⃣ Device is ready when LED turns green."

This approach shortens learning time and increases user satisfaction. Manual should also be accessible with PDF and online (web) versions.

37. Is there Quick Start Guide or QR code on product?​

Product should have easily accessible Quick Start Guide in box content or on it.

This guide informs user about first 3–5 steps required to operate device. Alternatively, QR code on device or package can direct to digital guide, installation video or support page.

QR link should always direct to long-lived web area (e.g., official product page). This method reduces support calls and integrates user into digital ecosystem.

38. Are user training or online support materials accessible (video, PDF, web portal)?​

User's learning process of device should not be limited to manual only.

Educational videos, interactive guides, PDF documents or online support materials accessible through web portal should be provided.

These contents may include:

• Visual demonstration assembly or maintenance videos
• Frequently asked questions (FAQ)
• Software update or calibration instructions

Support materials should be optimized to be accessible from both mobile devices and computers. Giving user freedom to access information at own pace directly increases satisfaction rates.

39. Is user feedback collected systematically (form, application, field team)?​

Product's performance after market launch should be continuously monitored through user feedback.

Feedback collection methods:

• Mobile application or web form
• Email / QR-based survey
• Field service teams or post-sales reports

Collected data should be regularly communicated to design team and classified (e.g., ergonomics, interface, performance). Systematic feedback collection process is first step of UX Loop — that is, it enables product to become living, evolving structure with user.

40. Is feedback included in product improvement process (UX Loop)?​

Collected user feedback should be active part of Product Iteration Cycle.

This information should not only be archived; it should become input affecting design decisions.

Example: "35% of users indicated that power button was not noticed → revision B: raised button + LED ring added."

This process should be managed with regular UX Review meetings between design team, software engineers and product managers. Systematic processing of feedback is strongest indicator of product's long-term success.

Tests and Evaluations​

41. Are user experience tests (UX test) conducted at prototype stage?​

User experience tests should be conducted not only with final product but at early prototype stage.

Goal in these tests is to measure product's intuitiveness and usability through real user behaviors.

Applicable methods:

• Observed prototype test (Usability Observation)
• Think-Aloud method
• A/B comparison tests
• Time measurement (task completion time)

Results of these tests should be basic data for design decisions and design revision should be made for each observation. UX tests conducted at early stage dramatically reduce user errors that may occur later.

42. Are user error situations analyzed and design revised?​

All erroneous behaviors, indecisions or misinterpretations observed in all user tests should be recorded as "user error log".

These errors should be evaluated as design guidance error, not software or hardware deficiency.

Example:

• User perceived power button as LED → button color and texture revised
• "Settings" icon in menu not understood → icon supported with text

These findings should be evaluated in regular UX review meetings and converted to product revision. This approach supports human error–resistant design principle.

43. Are ergonomic measurements (hand opening, screen angle, pressing force) verified with tests?​

Ergonomic design assumptions should be verified with physical tests.

Basic parameters to be measured:

• Hand opening / access range → Button positioning verification
• Screen angle / line of sight → Readability and reflection test
• Button pressing force → Average 60–100 gF (ergonomic limit)

44. Is user satisfaction survey (CSAT, SUS score) measured with target of 80 or higher?​

Product satisfaction should be measured with CSAT (Customer Satisfaction Score) or SUS (System Usability Scale) methods after user tests.

Target score: should be determined as SUS 80 or higher / CSAT 90% or higher.

These metrics objectively show how easily and satisfactorily product is used by user. This measurement should be repeated after each major software or hardware revision, score decreases should be fed back to product development process.

45. Are accessibility tests (contrast, navigation, labeling) completed according to standard?​

All digital and physical interfaces of product should be tested according to accessibility standards.

Test scope:

• Color contrast ratio: minimum 4.5:1
• Navigation structure: compatible with screen readers
• Labeling: "alt text" or tactile sign available for all buttons, icons and areas