PT Guide

Overview

PT Guide is an iPhone app I designed and implemented as the final project of my vocational training as a software developer. Its goal is to support blind and visually impaired people when using public transportation, using location tracking and VoiceOver technology to deliver audio cues during bus and train rides.

At the time of completion, PT Guide was, to my knowledge, the only app of its kind specifically designed for blind users.

The Challenge

Inspired by a news article about using the iPhone as a blind person and the, at that time, often missing auditory announcement systems in public transit, I decided to address this problem as an iPhone app specifically optimized for blind users. Key challenges included:

• Designing a navigation experience without any visual feedback.
• Understanding the mental model of blind users interacting with touchscreen devices.
• Ensuring reliability for safety-critical public transit guidance.
• Optimizing audio cues for noisy transit environments.

The Process

This project required extensive research and testing with blind users:

• Requirements Analysis: Interviews with blind iPhone users to understand their needs and interaction patterns with VoiceOver.

• Audio-First Interface Design: All non-text objects annotated with alternative descriptions accessible only through VoiceOver; layout designed for linear navigation since blind users cannot perceive a graphical interface from a bird's-eye view.

• Low-Fidelity Prototyping: Wireframes with hand icons illustrating VoiceOver interaction flows.

• Iterative Testing: All development milestones and the final version were tested both through automated methods and by blind iPhone users.

• Validation: Ensured the app functions according to the mental model of its target audience.

The Solution

Key features designed and built:

• Real-Time Transit Navigation: Enter a destination stop and receive audio notifications before arrival.

• VoiceOver-Optimized Flows: Every screen and interaction designed for linear, sequential discovery via VoiceOver.

• Favorites Management: Quick access to frequently used stops.

• Real-Time Distance Display: Live distance tracking to destination with audio updates.

• Audio Feedback System: Context-aware navigation cues adapted for transit environments.

Results & Impact

• At the time of completion, PT Guide was one of very few apps specifically designed for blind users — and the only transit navigation app of its kind.
• The extensive user testing with blind participants validated the audio-first design approach.
• Findings informed my understanding of accessibility design, which continues to influence my work today.

The app was discontinued in 2015 due to time constraints.