axiom-haptics

Haptics & Audio Feedback

Comprehensive guide to implementing haptic feedback on iOS. Every Apple Design Award winner uses excellent haptic feedback - Camera, Maps, Weather all use haptics masterfully to create delightful, responsive experiences.

Overview

Haptic feedback provides tactile confirmation of user actions and system events. When designed thoughtfully using the Causality-Harmony-Utility framework, axiom-haptics transform interfaces from functional to delightful.

This skill covers both simple haptics (UIFeedbackGenerator) and advanced custom patterns (Core Haptics), with real-world examples and audio-haptic synchronization techniques.

When to Use This Skill

• Adding haptic feedback to user interactions
• Choosing between UIFeedbackGenerator and Core Haptics
• Designing audio-haptic experiences that feel unified
• Creating custom haptic patterns with AHAP files
• Synchronizing haptics with animations and audio
• Debugging haptic issues (simulator vs device)
• Optimizing haptic performance and battery impact

System Requirements

• iOS 10+ for UIFeedbackGenerator
• iOS 13+ for Core Haptics (CHHapticEngine)
• iPhone 8+ for Core Haptics hardware support
• Physical device required - haptics cannot be felt in Simulator

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Part 1: Design Principles (WWDC 2021/10278)

Apple's audio and haptic design teams established three core principles for multimodal feedback:

Causality - Make it obvious what caused the feedback

Problem: User can't tell what triggered the haptic Solution: Haptic timing must match the visual/interaction moment

Example from WWDC:

• ✅ Ball hits wall → haptic fires at collision moment
• ❌ Ball hits wall → haptic fires 100ms later (confusing)

Code pattern:

// ✅ Immediate feedback on touch
@objc func buttonTapped() {
    let generator = UIImpactFeedbackGenerator(style: .medium)
    generator.impactOccurred()  // Fire immediately
    performAction()
}

// ❌ Delayed feedback loses causality
@objc func buttonTapped() {
    performAction()
    DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
        let generator = UIImpactFeedbackGenerator(style: .medium)
        generator.impactOccurred()  // Too late!
    }
}