Music Timing Intro: Teaching Rhythm Through Interactive PracticeMusical Note Timing Player

January 6, 2026

I’m excited to announce the imminent release of Music Timing Intro, an Android app designed to help children (and anyone else!) learn musical rhythm and note timing through hands-on practice. Source is already available on my github.

The Genesis

This app evolved from a simple musical quiz I built for my son when he was learning to read music. I noticed he understood the concept of note duration but struggled with the feel of timing. Reading that a whole note lasts four beats is one thing—actually holding a note for exactly that long is another skill entirely.

Traditional music education often separates theory from practice, but timing is inherently practical. You can’t learn it just by reading about it; you need to feel it. That insight drove the design of Music Timing Intro.

How It Works

The app presents a simple but effective learning flow:

See the note – Visual representation of whole, half, or quarter notes
Watch the metronome – An animated pendulum keeps perfect time at 60 BPM
Play it yourself – Press and hold a piano key for the correct duration
Get instant feedback – The app tells you exactly how close you were

The piano keyboard synthesizes audio in real-time using Android’s AudioTrack API, generating sine wave tones at proper musical frequencies (A3 through G4). The timing validation uses a tolerance window to account for human variability while still encouraging accuracy.

Screenshots

Here’s what the learning experience looks like in practice:

The Four Moods: Simple, Encouraging Feedback

The app uses a straightforward emotional feedback system designed for primary school children. It doesn’t dwell on past mistakes—it only cares about your current streak:

Sad: One wrong answer
Angry: Two or more wrong answers in a row
Happy: One correct answer
Delighted: Two or more correct answers in a row

This means you can have a low overall score but still see “Delighted” after getting two right—because recent success matters more than past struggles.

“Focus on the beat.” – Two wrong in a row. The feedback shows the gap (1.7 beats vs 4 expected), but the mood is about the streak, not the precision.

“Good effort – adjust the length.” – One wrong answer. Very close (0.1 vs 2 beats), but accuracy doesn’t matter—the system cares about right vs wrong.

“Nice – keep that groove.” – One correct answer breaks the losing streak! Back to positive mood immediately.

“Perfect. Keep that feel.” – Two right in a row, even with a low overall score (10%). Notice the metronome pendulum mid-swing—always keeping time.

Key Features Visible:

The Metronome: Always visible and moving—providing constant visual timing reference
Piano Keyboard: 7 white keys with Middle C labeled in cyan, plus black key stubs
Clear Instructions: “Play any note, of this length?”
Precise Feedback: Shows expected beats vs actual played beats for learning
Encouraging Messages: Different phrases for each mood to avoid repetition
Score Tracking: Always visible to show overall progress
Note Display: Clear visual of whole, half, or quarter notes

Why This System Works for Children:

Short memory, immediate feedback: Children don’t need complex scoring algorithms. They need to know: “Did I just get it right?” The streak-based system is:

Simple: Easy to understand (one right = happy, two right = delighted)
Forgiving: Past mistakes don’t haunt you—just get the next one right
Encouraging: Success is immediately celebrated
Motivating: Two in a row feels achievable, not overwhelming

The precision feedback (“Expected: 2 beats • Played: 1.8 beats”) is there for learning, but the emotional feedback is binary: right or wrong, based on the tolerance window. This separation keeps the emotional response simple while still providing detailed information for improvement.

You can see this philosophy in the “Delighted” screenshot—despite only a 10% overall success rate, getting two consecutive answers right earns full celebration. That’s by design. We’re building confidence, not perfectionism.

Why 60 BPM?

Initially, I tried 120 BPM, thinking it would be more engaging. User testing (with my son) quickly revealed the problem: it was too fast for beginners.

At 120 BPM, quarter notes last only half a second. Children struggled to process what they saw, react to press the key, hold it for the right duration, and release at the right time—all in 0.5 seconds. Too much cognitive and motor load.

Switching to 60 BPM changed everything:

Quarter note = 1 second (manageable reaction time)
Half note = 2 seconds (easy to feel and hold)
Whole note = 4 seconds (tests patience but achievable)

The key insight: Learning timing isn’t about speed—it’s about feeling the duration. 60 BPM gives space to experience the beat without rushing.

Yes, it can feel sluggish to experienced musicians. But this app isn’t for them. It’s for children taking their first steps into rhythm, where patience and accuracy matter more than tempo.

Educational Philosophy: Three Design Principles

1. Immediate Feedback Loop

Research shows immediate feedback accelerates skill acquisition. There’s no “submit” button for timing exercises—as soon as you release the key, you see results. This reduces cognitive load and keeps students in a flow state.

2. Multi-Modal Learning

The app engages multiple senses:

Visual: Note image + metronome animation
Auditory: Synthesized tone
Kinesthetic: Physical key press and hold

Different learners engage different senses, and combining them reinforces the learning.

3. Positive Reinforcement

The mood system progresses from Bored → Happy → Delighted for correct answers, with encouraging phrases like “Spot on – lovely timing” or “Nice – keep that groove.” Even incorrect feedback is supportive: “Close – hold it just the right amount.”

This builds a growth mindset rather than performance anxiety.

The 12-Key Insight: Why One Octave Is Perfect

When I started building this app, I worried that one octave wouldn’t be enough. Surely students need access to more notes?

Music education research disagrees.

The app currently uses 7 white keys (A3 through G4, centered on Middle C). Future versions will enable the 5 black keys, creating a complete 12-key chromatic octave. This might seem limited, but it’s actually pedagogically superior:

What you can learn with just 12 keys:

All 12 chromatic notes (sharps and flats)
Every major and minor scale (starting positions)
Basic intervals (minor 2nd through octave)
Chord construction (triads)
Key signatures and accidentals
Hundreds of simple melodies

The pedagogical insight: Mastery at one octave transfers instantly to all octaves. The patterns are identical. Once students understand the relationship between C and C#, they understand all half-step relationships.

Physical instrument comparison:

Melodicas for beginners: often 1 octave
Recorders: ~1.5 octaves (but beginners use far less)
Music Timing Intro: 12 keys = one complete chromatic octave

By keeping the keyboard to one octave, every key is large and touch-friendly. Children can play accurately without frustration. More keys would mean smaller targets and more errors.

One octave isn’t a limitation—it’s a deliberate design choice that prioritizes deep learning over superficial coverage.

The Surprising Market Gap

When I researched existing piano apps, I found dozens of options, but none doing what seemed obvious:

Most apps offer 88 scrollable keys (overwhelming for beginners)
Song-following games focus on entertainment over fundamentals
Apps with “adjustable keyboards” show arbitrary key ranges

What I didn’t find: An app designed around the principle that one chromatic octave is all a beginner needs.

It’s surprising this gap exists—the design seems perfect for phone screens and beginner education. But there’s a reason commercial apps don’t do this, and it reveals something important about the difference between commercial software and educational tools.

Why Commercial Apps Can’t Solve This Problem

There’s a reason most piano apps try to be everything to everyone: business models demand it.

A venture-backed app needs:

Long user retention (months/years)
Subscription revenue
Engagement metrics for investors
Upsell pathways

An app that teaches fundamental timing in 8-12 weeks has a “problem” from the commercial perspective: students graduate. When a child masters rhythm fundamentals and moves on to a real instrument or more advanced software, that’s user churn to a business analyst. But from an educational perspective, that’s success.

This is where open source shines. I don’t need:

Recurring revenue
User retention metrics
Engagement numbers
Growth curves

I need one thing: Does it teach timing effectively?

Open source enables focused, effective tools that commercial pressures would never allow. No feature bloat to justify subscriptions. No endless content to pad retention numbers. Just a tool that does one thing exceptionally well, then gracefully steps aside when the student is ready to progress.

This is why education and open source are such natural partners.

Technical Implementation

As a backend developer by trade, this project was a great excuse to dive deeper into modern Android development:

Jetpack Compose for the entire UI—no XML layouts
Redux/MVI architecture with pure reducer functions for state management
Kotlin coroutines for audio playback and timing
Material 3 design system for a polished look

The state management particularly interests me. Coming from a Spring Boot background, I’ve been exploring how patterns from web development translate to mobile. The reducer pattern provides the same predictability and testability I value in backend services:

kotlin

fun reduce(state: QuizUiState, event: QuizEvent): QuizUiState {
    // Pure function—same inputs always produce same outputs
    // Easy to test, easy to reason about
}

All the timing logic lives in the reducer, making it straightforward to verify correctness without involving UI or audio systems.

The metronome animation is built with Compose’s Canvas API, demonstrating that custom drawing in Compose is both powerful and elegant. The pendulum swings using animateFloat with LinearEasing and RepeatMode.Reverse, synchronized perfectly with the 60 BPM tempo.

What’s Next

This is version 0.1.0—focused purely on timing with white keys at a single tempo. Based on interest and feedback, future versions could include:

Tempo progression (60 → 90 → 120 BPM) as users master timing
Black keys enabled – The visual stubs are already there; they’ll “grow” and become interactive at advanced levels
Note recognition – Learn to identify and play specific notes (not just timing)
Staff notation – See notes on a musical staff and play them
Combined exercises – Play the right note for the right duration

The architecture makes these additions straightforward—the reducer pattern means adding new question types is just adding new cases, not refactoring everything.

If there’s interest, I plan to develop similar educational music apps:

Pitch recognition trainer
Interval identification
Rhythm pattern matching
Sight reading practice

Open Source and Free

Music Timing Intro is free and open source under GPL-3.0. The source code is available on GitHub.

I believe educational tools should be freely accessible. No ads, no tracking, no in-app purchases—just a tool for learning music.

Download and Try It

The app will soon be available on F-Droid. In the meantime, you can:

Download the APK from GitHub Releases
Build from source: It’s just ./gradlew assembleRelease
Report issues or suggest features on GitHub

For Educators and Parents

This app is perfect for:

Children learning to read music
Beginning music students practicing rhythm
Anyone wanting to improve their sense of musical timing
Supplementing traditional music lessons

The focus on one fundamental skill—timing—means it works well alongside other learning methods. Master timing here, then apply it everywhere else.

For Developers

If you’re interested in Android development with Kotlin and Compose, the codebase demonstrates:

Clean architecture with separation of concerns
Pure functional state management with reducers
Custom Canvas drawing for animations
Real-time audio synthesis with AudioTrack
Gesture handling with Compose
Progressive complexity through feature flags

Feel free to explore the code, learn from it, or contribute improvements!

From Backend to Mobile: A Personal Note

As a backend developer with over 20 years of Java experience, I’ve been exploring modern Android development over the past year. This project builds on earlier work—I created a musical quiz app for my son and have built several personal Compose apps to learn the platform.

The journey from backend Spring Boot development to modern Android has been remarkably smooth. Good architectural principles—separation of concerns, pure functions, immutable state—translate beautifully across platforms. The reducer pattern I use here feels natural coming from backend services where predictable state transitions are crucial.

What surprised me most about Compose is how well it handles complexity. This app manages:

Real-time audio synthesis
Gesture detection with timing precision
Animated metronome synchronized to tempo
State machines for quiz progression

All with clean, testable code. The declarative UI paradigm from Compose paired with Redux-style state management creates a development experience that rivals—and in some ways surpasses—what I’m used to in backend work.

Download: GitHub Releases
Source Code: GitHub Repository
License: GPL-3.0

Have you used the app? Found it helpful? I’d love to hear your feedback—especially from music teachers and parents!

Tags: #Android #Kotlin #JetpackCompose #MusicEducation #OpenSource #Education #MobileApps