Poynt: Tactile UI for Accessibility
- Client
- Poynt
- Year
- 2016
- Scope of work
- User ResearchInteraction DesignPhysical Prototyping3D ModelingUsability Testing
- Location
- Palo Alto, CA
Poynt is a point-of-sale platform providing smart payment terminals, software, and apps for business management. During a 14-week internship I developed a hardware and software solution to make their touchscreen terminal accessible to blind and visually impaired users. The ADA-compliant design was implemented in 50,000 terminals deployed across Brazil.
Opportunity
How can we enable blind and visually impaired users to securely enter their PIN on a touchscreen payment terminal? The solution had to comply with ADA and Brazilian accessibility laws, meet strict security and fraud-prevention standards, and work within hardware and manufacturing constraints. It needed to accommodate blind users who rely on tactile feedback, and low vision users who benefit from visual cues like contrast and layout familiarity.
What I did
- Led user research with accessibility experts and individuals with visual impairments.
- Explored and tested multiple hardware and software concepts within technical and cost constraints.
- Designed a tactile frame with Braille markers and a corresponding custom PIN entry interface.
- Built low- to high-fidelity prototypes using cardboard, PVC foam, and 3D printing.
- Conducted usability testing with blind and low-vision participants.
- Created final mockups and 3D models for stakeholder approval and production handoff.
Research
I didn't have prior experience designing for visual disabilities, so I met with the Associate Director of the Vista Center for the Blind and Visually Impaired in Palo Alto to understand how people with varying degrees of vision impairment navigate technology. At the time most payment terminals still used physical keypads, and vision impaired users relied on a raised bump on the 5 key to orient themselves. Touchscreens lacked these built-in affordances.
After evaluating a range of approaches — from haptic feedback and gesture input to audio-based solutions — I ruled out many options on feasibility, cost, security, or hardware compatibility. External pin pads were too costly for buyers, and headphone jacks posed privacy and technical issues. We also could not cover any part of the touchscreen with a tactile overlay.
Physical + digital prototyping
I began prototyping tactile overlays by hand using cardboard and PVC foam. The idea was a frame that could sit on top of the screen without obstructing touch. I paired it with a custom PIN entry interface matching the frame's layout, so users could feel for a number, slide a finger in, and double tap to confirm.
I first arranged the numbers in a circle to minimise screen contact, but early feedback showed people expected a left-to-right, top-to-bottom flow, so I revised the layout.
To explore materials I visited local craft stores and experimented with thermoplastics, building mid-fidelity prototypes from PVC foam that could be cut and reshaped with heat. When I needed something more durable to test with, I taught myself SketchUp, modelled the frame in 3D, and partnered with a local makerspace to print it.
Usability testing
I returned to the Vista Center to test with one blind and one low-vision participant, both over 50, and the two sessions pulled in opposite directions.
The blind participant responded well to the tactile interface and suggested reordering the numbers to read naturally across rows. The low vision participant struggled with it and said he preferred the traditional keypad layout — just with more clarity and contrast. That split is why the final design is two designs: I built a separate high-contrast version of the conventional PIN interface, with bold text, colour cues, and a highlighted 5 key for orientation.
Solution
The final design is two complementary solutions: a tactile frame with Braille markers aligned to a custom PIN interface for blind users, and an enhanced high-contrast version of the existing keypad for low vision users. The tactile route allows a PIN to be entered through guided touch and double-tap input; the visual route prioritises clarity, contrast, and familiarity.
Both are secure, and neither requires significant modification to the touchscreen hardware, which is what made the design scalable and cost-effective to implement. It was reviewed and approved by internal stakeholders and accessibility experts, then prepared for manufacturing.
The accessibility solution was submitted for a patent and approved for production. It was implemented across 50,000 Poynt terminals deployed in Brazil.
Quickstart guide
I also designed the quickstart guide that ships in the box with the terminal. It's one folded sheet covering the four things a merchant does first: placing the device, plugging it in, loading the printer, and powering on.
I sketched the steps in a notebook, then cut and folded paper dummies so I could check that each panel appeared in the order someone would actually open it. I drew the final illustrations and labelled the parts, and kept the guide almost entirely visual so it wouldn't need translating.