Digital product design · Master's thesis, UDIT 2025

PRISMA

PRISMA home on Android: the hexagonal avatar, suggestions such as “How can I help you today?” and the bar with Activity, microphone and Profile

A voice assistant that understands you, adapts to you and protects your privacy. Designed around the reasons people stop talking to their assistant today.

Method
Double diamond
Platform
Android app, Material 3
Outcome
Tested prototype

Problem

Voice assistants live in our phones, cars and TVs. Almost nobody uses them.

The technology is there, but people don't adopt it. Next to ChatGPT, the usual assistants feel outdated.

They don't understand

Accents, pauses and natural language lead to errors and frustration.

They don't solve

Complex tasks push people back to the touchscreen.

They don't earn trust

Fear of always-on microphones and of how personal data is used.

Context

In Spain, people know AI but rarely use it

Europe looks at AI with neutrality, neither excitement nor fear. That leaves room for products that earn trust.

72.9%

say they know what artificial intelligence is

47%

have never used an AI-based tool

15.2%

describe it in a single word: “dangerous”

37.1%

feel neutral about it after using it

Source: AIMC, Navegantes en la Red 2024.

Method

Double diamond in four phases

Design an experience that complements conversation with a language model and strengthens emotional connection and usability.

Understand the problem
Build the solution
1Discover
2Define
3Develop
4Validate

Desk research, survey, interviews, benchmark and AS-IS journey.

Brainstorming, SCAMPER, criteria matrix, persona, TO-BE journey and architecture.

Low-fidelity wireframes and an interactive Figma prototype.

Usability testing with real users, then iteration.

Discover

98 responses and 8 interviews

A snowball survey and interviews with users aged 24 to 68, with and without experience, plus UX and technology experts.

55%

use voice assistants regularly

40%

often have frustrating experiences

What would motivate them most

“If it understood what I say better”

50 votes, the most chosen option

They blame themselves

When it fails, they think “I didn't say it right”.

Shallow use

It stays at music, weather and alarms.

A screen helps

Voice works better with visual support.

Alexa feels outdated

Next to ChatGPT or Gemini, command-and-response falls short.

Insights

Three truths behind the rejection

Seven categories came out of the surveys, interviews and usage tests. These three explain the rest.

First impressions are final

If it fails at the simple things, people assume it's no good and keep their use shallow.

ChatGPT raised the bar

People expect a collaborator that converses fluently, not command-and-response.

Intimacy without trust

People want a personal, emotional assistant, but privacy fears get in the way of that bond.

AS-IS customer journey

The conversation, as it happened

A professional gets home and asks her assistant for things. Purple is what she says; grey is what the assistant does.

Stage 1

Arriving

“Play some relaxing music”

Plays random music

“No, play Shakira”

Plays a different song

Stage 2

Activities

“Make me a coffee”

“To make a coffee, you need…”

“Turn on the coffee machine and make me an espresso”

Now it does it

Stage 3

Complex tasks

“What can I do tonight with my partner?”

Answers something irrelevant

Gives up on voice and searches on her phone

Stage 4

Night

Doesn't show whether it's still listening

She hesitates, then unplugs it

AS-IS service blueprint

Where the experience breaks

Top: how she feels at each of the ten moments on the map. Bottom: what happens in front of and behind the voice.

Arriving
Activities
Complex tasks
Night
HappyNeutralFrustrated
She does
Says hello, adjusts the house and asks for music
Asks for a coffee and has to repeat herself
Asks for a plan and ends up searching on her phone
Unplugs the assistant
The assistant responds
Plays random music and gets the artist wrong
Gives instructions instead of making the coffee
Answers something irrelevant and loses the thread
Turns off without any confirmation

Line of visibility: she can't see what's below
Behind the scenes
Speech recognition fails on proper names
Doesn't link “make” to the connected coffee machine
No recommendations or continuity with the phone
No privacy indicator or private mode
Where it breaks
Poor recognitionIndirect actionsLimits with complexityDistrust

Define

Three proposals, one chosen

Brainstorming and SCAMPER on the pain points and insights, scored with a matrix of security, innovation, feasibility and impact.

Proposal 1

Multiple personas

Several agents with their own name and style, memory per context and hand-off between devices.

Proposal 2, the chosen one

Empathy and privacy

Emotion detection, adaptation to age and context, a private mode and an onboarding that explains the safeguards.

Proposal 3

Collaborative agents

Coordinates with other agents and syncs data across devices and apps.

Service concept

A voice assistant for everyone: personal, empathetic and safe.

It detects emotions, adapts to context and age, protects privacy with a dedicated mode, connects to authorised apps and keeps continuity between conversations.

The proposal

PRISMA, an assistant that understands you

Emotion detection

Picks up on tone of voice and adjusts its own.

Age and culture

Adapts to origin, dialect and age.

Context and place

Changes depending on where it's installed.

Guided onboarding

Teaches its features and privacy safeguards.

Private mode

Conversations that aren't saved.

Continuity

Across devices and authorised apps.

PRISMA home with the avatar winking while it suggests “Let's create a workout routine”

User persona

Diana, 41, Madrid

Project manager at a digital marketing agency. Surrounded by connected devices.

Portrait of Diana, a 41-year-old woman with curly hair and a green sweater, smiling

“If my voice assistant can't do it for me, I'll have to do it by hand.”

Goals

  • Save time every day
  • Stay on top of things and organised
  • Be more productive
  • Enjoy more free time

Needs

  • Automate her routines
  • One place for her schedule
  • Useful answers by voice
  • Privacy for her data

Frustrations

  • It doesn't understand complex requests
  • Apps that don't connect
  • Doubts about privacy
  • Generic answers

Her ecosystem

Google AssistantAlexaSpotifyGoogle CalendarSmart home

Personality

BusyHas time
MessyOrganised
IndependentTeam player

TO-BE customer journey and blueprint

How PRISMA responds at every step

First contact with the app, from download to first real use. Each label at the bottom answers a friction from the AS-IS.

Welcome
Voice and profile
Guide and permissions
First use
HappyNeutralFrustrated
She does
Installs the app and listens to the intro
Chooses her voice, name and language
Tries commands and connects her apps
Creates a reminder and asks for music
PRISMA responds
Says hello and explains what it can do
Offers voice samples and confirms her details
Runs demos and shows its policies
Confirms the action and turns on night mode

Line of visibility: she can't see what's below
Behind the scenes
Cloud sign-up and onboarding script
Real-time generated voice and saved profile
Up-to-date policies and APIs that sync apps
Calendar, weather and traffic connected
What it solves
She knows what to askIt adapts to her voiceVisible privacyIt acts, not explains

Develop

Built on Material Design 3

Google's native design system for Android: its colour scheme, Roboto type and standard components. The app feels native to the system, with nothing new to learn.

Primary#6750A4
Primary container#EADDFF
Secondary container#E8DEF8
Tertiary container#FFD8E4
Surface#FEF7FF
On surface#1D1B20
Filter chips with Music, Food, Social media, Innovation and Technology selected
Filter chips
Material 3 dialog asking permission to record audio, with Accept and Don't allow
Dialog
Three switches turned on under Quick preferences
Switches
List of radio buttons with the Sol option selected
Radio buttons
Lilac tonal button labelled Siguiente (Next)
Tonal button

Prototype

An onboarding that listens before it speaks

First contact gathers origin, interests and voice, and asks permission before recording. Screens from the v2 prototype in Figma.

Screen asking whether to allow Prisma to record audio
Explicit permission
Where did you grow up? screen with country and city
Origin and culture
Interests screen with selected chips and quick preferences
Interests
Calibrating your voice screen with a microphone inside a hexagon
Voice calibration
Screen to choose the voice tone, with Sol selected
Assistant's tone

Screens are in Spanish, the language the prototype was tested in.

Develop

From wireframes to high fidelity

Wireframes surfaced gaps in the flow before content, interactions and animations were added.

Greyscale wireframes: home with the avatar, activity list and conversation history
Low fidelity: structure and flow
PRISMA home
Home
Activity history with habit analysis, shopping list and daily summary
Activity

Validate

The flow works; the signposting, not quite

Usability test with three participants, measuring task success and perceived satisfaction.

100%

of tasks completed by all 3 participants

2 of 3

rated the experience positively

Low

number of errors while navigating

What failed

People didn't always recognise which section each screen belonged to.

What it taught

Accepting an assistant also depends on perceived usefulness and autonomy, not just usability.

Iteration

Six changes from the tests

Each change answers something participants didn't get the first time.

ScreenObserved problemChange made
HomeMicrophone hard to recogniseReactive button with active and inactive states
WelcomeUnclear when to record your nameCall-to-action text
ActivityThree different interpretationsExplanatory contextual text
HistoryLooked like an editable chatText explaining it's accumulated information
Private modeMic state and getting back to HomeHome icon and a countdown
CultureSettings felt isolatedMerged into the profile and onboarding
Home bottom bar: inactive microphone in light lilac and active in dark
Reactive microphone: inactive on the left, active on the right
Welcome screen: Hi, my name is PRISMA, what should I call you? Tap the screen
“Tap the screen” cue
Private mode notice: nothing will be saved and after 5 minutes without interaction it returns to the start
Notice with the rules
Private mode on: avatar with sunglasses, countdown clock and Home icon
Clock and way back Home

Conclusions

What the research leaves us

In Spain, AI sits in a neutral, cautious place: people know it, but understand it little.

The barrier is understanding

Not the interface. Ambiguity and accents frustrate people; voice needs a multimodal design with visual support.

Acceptance goes beyond use

It takes real usefulness, autonomy over decisions and clear control of privacy.

PRISMA brings something different

Emotion, cultural adaptation and apps connected through standards such as MCP (Anthropic, 2024).

Today's technical limit

Today it would work in the foreground, without a background wake word. Technology is expected to make that possible.