Human-Computer Interaction. Designing Usable, Accessible and AI-Ready Interfaces, with Java and Python — Bu Ratna’s warung takes the same order — two iced teas, one fried rice, one geprek chicken — on two different screens, and on one of them customers give up halfway. An elderly patient stands in front of a puskesmas queue kiosk and cannot find the button she needs.

Overview

Chapter 1 explains why interfaces matter, following Bu Ratna’s warung as it goes online: what HCI is, how it grew from punched cards to AI agents, why it matters in Indonesia in 2026, and it sets up the workbench.

Chapters 2 and 3 lay the foundations. Chapter 2 watches Bu Siti at a puskesmas kiosk to explain the human factors that no software update can change — perception, attention and memory — and turns Fitts’s and Hick’s laws into calculators. Chapter 3 follows Mbak Dewi’s laundry as it leaves WhatsApp, presents Norman’s principles and the families of design heuristics, meets the design languages of 2025–2026, and builds a heuristic-evaluation report generator.

Chapters 4 to 7 teach the process of designing the right thing. Chapter 4 helps an ojek base that wants an app with the human-centred design process of ISO 9241-210, the Double Diamond and design thinking, and looks at AI in the design process of 2026. Chapter 5 finds out why Bu Rina’s laundry is losing customers with interviews, contextual inquiry, surveys and the coding of qualitative data. Chapter 6 prototypes a puskesmas queue kiosk, from paper to wireframes, clickable mockups and a coded prototype. Chapter 7 evaluates the pre-orders at Warung Bu Tini with heuristic evaluation, usability tests, performance measures and the SUS and UMUX-Lite questionnaires.

Chapters 8 to 10 are about the interface itself. Chapter 8 redesigns a rural bank’s app with Gestalt, visual hierarchy, typography, color and contrast, design systems and information architecture. Chapter 9 compares the ways of ordering at Bu Tini’s counter — GUI, touch, voice and gesture — with one order core and three front ends. Chapter 10 designs for Mas Yoga’s budget phone, measuring a mobile-first booking page in a real browser at four widths and on three networks.

Chapters 11 and 12 are about people who are too often left out or misled. Chapter 11 makes a puskesmas website accessible with WCAG 2.2 and the laws that now require it, and tests it in four layers. Chapter 12 examines the membership flow of Bu Sri’s laundry to show emotional design, trust, dark patterns and honest consent, and lints a consent flow automatically.

Chapters 13 to 15 look at the interfaces that are arriving now. Chapter 13 designs Bu Wati’s midnight order assistant — chat, copilots and agents — around confirmation, undo and calibrated trust. Chapter 14 settles arguments about Bu Tini’s quiet checkout with analytics, funnels, A/B experiments and metrics. Chapter 15 follows Mbah Sumi and a queue screen into spatial, wearable and ambient computing, with target sizes and dwell times computed rather than guessed.

Chapter 16, the capstone, designs and evaluates a complete interactive system: a self-service queue kiosk for Puskesmas Sehat Selalu, from research at the registration desk to a working bilingual kiosk and the evidence that it helps its patients.

Every chapter follows the same path: a situation from everyday Indonesian life, the idea in plain words, the theory with its evidence, a hands-on method with templates and checklists, a small companion program in Java and Python where it helps, running and testing it, HCI in practice at Profitina, common mistakes, a summary, exercises with complete solutions, and references.

Every program in this book was run before its output was printed. The programs are collected, chapter by chapter, in the accompanying Code folder, from Chapter01 to Chapter16, each with a java and a python folder, the data it needs, and a README that explains how to run it in a terminal and in VS Code on Windows, macOS and Linux.

Inside the Book

1. Introduction to HCI: Why Interfaces Matter
2. Human Factors: Perception, Cognition, Memory, Fitts’s and Hick’s Laws
3. Design Principles and Heuristics
4. User-Centered and Design-Thinking Processes
5. User Research Methods
6. Prototyping: From Paper to Interactive (and AI-Assisted) Prototypes
7. Usability Evaluation and Testing
8. Visual Design, Design Systems and Information Architecture
9. Interaction Styles: GUI, Touch, Voice, Gesture
10. Mobile and Responsive UX
11. Accessibility and Inclusive Design (WCAG 2.2)
12. Emotional Design, Trust and Ethical UX
13. Designing AI Interfaces: Chat, Copilots and Agents
14. Data-Informed UX: Analytics, Experiments and Metrics
15. Emerging Interfaces: Spatial, Wearable and Ambient Computing
16. Capstone: Designing and Evaluating a Complete Interactive System