Ray Tsai
中文 Contact

AI products · HCI research · Web

I build AI products that help people speak, learn and connect.

I'm Ray Tsai, in the AI master's program at NTU CSIE (HCI Lab). I moved from speech-recognition research into human–computer interaction, shipped an AI speaking-practice app on my own, and build websites for communities and programs.

See my apps Get in touch
Full résumé2 pages・PDF
Ray Tsai giving a thumbs-up in front of the Google sign and colorful lobby wall
NTU CSIE · HCI Lab
MirrorLive on the App Store

Web design service

A website for your shop or studio

Student pricing for simple showcase websites for small shops, studios and individuals. Limited slots each month.

See websites first Talk about your site

Websites I've built

Community site

2K Pickleball Club

Real-time Three.js paddle and ball that perform as you scroll

Visit site (opens in a new tab)

Program recap

NTU Silicon Valley program recap

29% shorter on phones (14,848 → 10,601 px)

Visit site (opens in a new tab)
Demo data

Lab activity platform

HCI Lab FUN LAB

Sign-ups, wishes, votes and albums in three languages

Internal lab platform · invite code required · screens show demo data

Community brand site

Taiwan Founder House

Main site plus a narrative recap subsite with 15 students' videos

Visit site (opens in a new tab)

From speech research to HCI — and products that ship

Research taught me how to measure; products taught me what to cut. Here is where I study and what I have done.

Read my full résumé2 pages・PDF

Research

2025/6 – 2026/3

CKIP Lab, Institute of Information Science, Academia Sinica

Part-time research assistant

Entrepreneurship program

19th

19th cohort (2026)

15

SV program, first cohort

NTU Creativity and Entrepreneurship Program

19th cohort (2026); also one of the 15 students in the inaugural NTU Silicon Valley Exploration Program cohort.

Summer 2026

≈7weeks

NTU Silicon Valley exploration program

About seven weeks in Silicon Valley doing market research and expert interviews, followed by the Demo Day on Sep 12.

Read the seven-week recap (opens in a new tab)
Group photo at night
Group photo at night
Group photo at the office
Group photo at the office
Sunset at Yosemite
Sunset at Yosemite
Sharing at an office in Silicon Valley
Sharing at an office in Silicon Valley
Group selfie at Google
Group selfie at Google

Film · YouTube · 10:36

I turned my seven weeks into a film

Seven Weeks in Silicon Valley | Growing Into My Own Voice

YouTube video cover: 7 Weeks in Silicon Valley Play video · 10:36：Seven Weeks in Silicon Valley | Growing Into My Own Voice (YouTube)

YouTube loads only after you press play.

Watch on YouTube (opens in a new tab)

Turning research and curiosity

into tools people use daily

A shipped app, and products in progress

Mirror home screen with pixel character
Mirror voice fingerprint result

Live on the App Store

Mirror – AI Speech Coach

An AI speech coach: record your spoken answer, and Mirror transcribes, scores and rewrites it for clarity and structure — then plays the better version back in your own cloned voice.

  • Voice signature in 30 seconds
  • Mock interviews in English, Chinese, Japanese
  • Side-by-side replay of original vs. improved
  • Five-axis voice radar

Built solo · iPhone · Free

View on the App Store(opens in a new tab)

More projects

Open a project to see its screens, status and links.

Echo iOS · Chrome
Echo product page

A podcast player that remembers every 15-second rewind: it keeps the sentence you replayed, diagnoses why you missed it (vocabulary, linking, speed…), and turns it into tomorrow's speaking practice. The Chrome version does the same with YouTube captions.

  • iOS: invite-only TestFlight beta
  • Chrome extension: in development
Product page (opens in a new tab)GitHub (opens in a new tab)
Rayality Projection Mapping Web · Open source
Rayality editor corner-pinning and projector output

Projection mapping in the browser: import images or video, drag four corners to correct perspective, and send the output to a projector from a separate window. No API key needed for the core workflow; optional Google Veo generation with your own key.

  • Live · open source
Open the editor (opens in a new tab)GitHub (opens in a new tab)
MedBuddy Web · LINE bot
MedBuddy caregiver dashboard (demo data)

A prototype for medication understanding and care handoffs for older adults on many medicines: rule-based checks, and two LINE accounts sharing one care record between elder and caregiver. Medication-bag photo readings must be confirmed by a person before they are saved. Built in about 48 hours during a build challenge.

  • Prototype · demo data
Open the prototype (opens in a new tab)GitHub (opens in a new tab)
Echo product pageRayality editor corner-pinning and projector outputMedBuddy caregiver dashboard (demo data)

By the numbers

Page views
No data yet
Public GitHub repos
9
Apps & products
4
Websites built
4
Apps live on the App Store
1 (Mirror)
Silicon Valley program
7 weeks
Mirror interview languages
3 (EN / ZH / JA)
Mirror voice signature
30 seconds to set up

Contact form

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Full résumé

Download PDF Open in new tab(opens in a new tab)

蔡秉叡 Ray Tsai

linkedin.com/in/ray-tsai-8908bb212(opens in a new tab)github.com/rick-ray-wldd(opens in a new tab)

Research & Product Focus

Multimodal human-computer interaction, sports coaching technology and voice AI. Combines basketball tactical knowledge, study design and product development to explore how personalized audio can support learning and real-world practice.

Education

National Taiwan University (NTU)Feb 2026 – Present

M.S. student, Computer Science and Information Engineering, Artificial Intelligence Program

  • HCI Lab, advised by Prof. Mike Y. Chen(opens in a new tab); multimodal interaction, emotional voice and AR/VR interfaces.
  • Spring 2026 GPA: 4.04/4.3 (15 credits). A+ in Multimodal HCI, Natural Language Processing, Artificial Intelligence, and Web Programming; additional coursework in Big Data Systems.

National Yang Ming Chiao Tung University (NYCU)Sep 2021 – Dec 2025

B.S. in Electrophysics

  • GPA: 4.1/4.3 over the final four semesters. Graduate-level coursework: Machine Learning for Signal Processing (A+), Speech Signal Processing (A+), Deep Learning (A), and AI and Law (A+).

Research Manuscript Under Review

CoachCast - Player-Specific Audio for Basketball Practice2026

Coauthor | Submitted to ACM CHI 2027; under review

  • Contributed basketball tactical guidance and recommendations, experimental design, and data annotation to a study of concurrent, player-specific audio guidance during coach-led team practice.
  • The project examines how personalized audio supports coordinated player actions alongside team-wide coaching, including trade-offs around guidance timing and player autonomy.

International Entrepreneurship Experience

NTU Silicon Valley Exploration ProgramJul – Aug 2026

Selected participant, inaugural 15-student cohort | San Francisco Bay Area, USA

  • Completed seven weeks of startup exploration, industry visits and founder exchanges; presented product progress and reflections through weekly NTU Day sessions at Startup Island TAIWAN.
  • Brought hands-on product feedback to IrisGo's cofounder and CTO: reproduced a Windows integration detection issue and narrowed likely causes to environment, executable detection and launch behavior.
  • Discussed creator voice-generation workflows with Influenxio's founder; translated ecosystem feedback into Echo's language-learning direction and a subsequent expressive-voice editing prototype.
  • Presented at Pre-Demo Day and developed MedBuddy for AI Fund's Engineer in Residence Build Challenge; continued product development and professional relationships after returning to Taiwan.

Selected Products

Mirror - AI Speech Coach(opens in a new tab)Apr 2026 – Present

Solo Founder | App Store release; 2026 NTU AI Builders Challenge entry

  • Built an end-to-end coaching app that analyzes spoken answers and replays revised responses in the user's cloned voice, supporting Traditional Chinese, English and Japanese.
  • Implemented voice calibration, streaming TTS, mock interviews and onboarding with Expo/React Native, Next.js and Supabase.
  • Reached 718 organic signups; shipped voice calibration, practice and feedback as a complete mobile learning workflow.

Echo - Contextual Language LearningJul 2026 – Present

Cofounder & Product Developer

  • Built a podcast-learning prototype linking playback and transcripts with vocabulary capture and replay; uses rewind behavior as a signal for comprehension support and follow-up shadowing practice.
  • Lead product development with a cofounder (NTU Information Management), who handles native Swift, Dynamic Island, system playback controls and practice cards.
  • Exploring browser-extension workflows for learning from video and other media beyond podcasts; developing Echo through NTU entrepreneurship coursework.

MedBuddy - Medication-Care Prototype(opens in a new tab)Jul 2026

AI Fund Engineer in Residence Build Challenge submission

  • Delivered a web dashboard and LINE-based care prototype during a 48-hour build challenge, connecting older adults and family caregivers; collaborated on LINE transport and reminder scheduling.
  • Separated deterministic medication-rule verdicts from AI explanations and documented rule provenance. Project validation recorded 316 passing tests; prototype has not undergone clinical validation.

Emotional Voice - Creator Voice EditingSep 2026 – Present

Independent Developer | Single-user local prototype

  • Built a take-comparison workspace with manual and AI-assisted editing, change previews, undo, candidate listening and WAV export; 11 integration tests and desktop/mobile checks passed.
  • Compared English, Chinese and mixed-language voice-clone recordings through controlled generation and exploratory listening. Investigating creator advertising workflows informed by discussions with Influenxio.

Research Experience

Research Assistant (Part-time), Academia SinicaJun 2025 – Mar 2026

CKIP Lab, Institute of Information Science | Dr. Wei-Yun Ma

  • Worked on multimodal language models and emotion-aware speech generation; contributed progressive SpecAugment scheduling and dialect-aware conditioning to the 2025 Formosa Speech Workshop Challenge team's low-resource Hakka ASR work.
  • Surveyed Kimi-Audio for joint emotion recognition and controllable speech generation.

Research Assistant, National Tsing Hua UniversityMar 2023 – Jul 2025

Institute of Learning Sciences & Technologies

  • Co-developed a multimodal AI picture-book platform combining speech synthesis and image generation for language learning and cognitive therapy; taught 12 hours per semester of generative AI and n8n/LangChain workshops.

Shadow Your Perfect SelfMay – Jun 2026

NTU Multimodal HCI course research project

  • Built and evaluated a three-condition self-voice shadowing platform with 12 participants; observed preference for self-voice models, while objective measures did not establish pronunciation gains.

Athletics, Leadership & Service

  • NTU Varsity Basketball Team, Forward (Fall 2026 - Present): joined this semester; registered for the 2027 北市大盃 tournament.
  • C-Level Basketball Coaching License (Taiwan): certified basketball coach.
  • NTU Creativity and Entrepreneurship Program, 19th cohort (2026); selected for High-Tech Entrepreneurship and Operations, a 12-student course (Fall 2026).
  • Public Relations Officer, NYCU Electrophysics Student Association (2022-2023): hosted 9 career seminars with 700+ total attendees and speakers from semiconductor and photonics companies.
  • Awards: Runner-Up, Law Broker GPT PLUS+ AI Competition (Jan 2024); Honorable Mention, 美術竹梅 Hackathon (2023).
  • ITRI Research Intern (Oct 2022 - Jun 2023): Python tools for automated data collection. DuPont Taiwan IT Intern: corporate IT workshops and network maintenance.

Ping-Juei (Ray) Tsai | September 2026

Public version without phone or email — to reach me, please use the contact form on this site. Go to the contact form