Product design question
Design a vending machine for blind people.
- Product design
- Medium
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What this question tests
Tests accessible product design: identifying real barriers blind users face with a visual, touchscreen-heavy device and designing around non-visual interaction.
How to approach it
- Clarify the user: someone fully blind using screen-reader habits and tactile or audio cues daily, interacting with an unfamiliar public machine.
- Identify pain points: can't read labels, prices, or a touchscreen menu, and can't visually confirm the right item or correct change.
- Identify the core job: independently select and purchase a known item without sighted help, and trust the transaction completed correctly.
- Propose a tactile keypad with braille and raised buttons mapped to voice-announced categories, plus audio confirmation of item and price before purchase.
- Address payment: tap-to-pay via phone or card with audio confirmation of the charged amount, avoiding cash and change handling where possible.
- Define success: independent transaction completion rate for blind users in usability testing, and audio-error report rate.
What a strong answer includes
- Rejects a touchscreen-only interface and proposes a tactile-plus-audio interaction model matching real blind user habits.
- Addresses payment specifically, avoiding cash and change ambiguity, a concrete trust risk for a blind user.
- Uses audio confirmation at each step, selection, price, dispensing, rather than a single accessibility bolt-on.
- Defines success with an independent-completion usability metric, not a generic satisfaction score.
Common mistakes
- Treating accessibility as a screen-reader-only add-on to an otherwise unchanged touchscreen machine.
- Ignoring payment and change-handling, a major real barrier for blind users at a physical machine.
Likely follow-up questions
- How would you validate this design with real blind users before deployment?
- How would you handle a jammed item without visual feedback?
More product design questions
- Design a TV for a car.Google · Product design · Hard
- Design a refrigerator for the blind.Google · Product design · Hard
- How do you design a camera for the elderly?Google · Product design · Medium
- Redesign Twitter for eCommerce.Shopify · Product design · Hard
- How would you go about designing a new location sharing app for Google?Google · Product design · Medium
- How would you improve Google Home?Google · Product design · Easy
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Learn the skill behind it
Chapters of the AI PM course that teach what this question tests.
- Chapter 4: Discovery and strategy for AI products
- Chapter 7: AI UX and human oversight: design for a system that is wrong sometimes
- Chapter 14: Get the job: the AI PM interview loop