Contact person: Business Client

Phone:Show

Email:Show

Location: Liberal, United States

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"I am ready to bring a patent-pending acoustic concept to life and need a mobile developer who can own the build end-to-end for both iOS and Android. The core of the job is straightforward: The app collects one user input (birth body length in meters), applies a proprietary physics-based equation to compute the user’s base resonance frequency (F₀), and instantly generates a tone ladder from that value. The user can toggle between two ladder modes:
Octave ladder (harmonic and sub-harmonic steps by powers of 2)
Golden-ratio ladder (harmonic steps by φ in both directions)
The resulting frequencies must be displayed immediately and each must be playable as a pure synthesized sine wave (not audio files), through the device speaker or headphones, with proper fade-in/fade-out to avoid digital clicks. In addition to pure sine tones, the architecture must allow for future expansion where the user may choose alternative playback sources for each frequency, such as:
Uploaded or pre-installed ambient audio files
Professionally-produced harmonic textures mapped to ladder frequencies
Purchased or commissioned sound packs unique to a user profile
For Phase 1, only pure synthesized sine tone playback is required.
The system must simply be designed such that this custom-audio layer can be integrated later without rewriting core logic.

The calculator must feel snappy—no lag between input, calculation, and playback. From there, real-time tone generation should stay flexible. Continuous playback is an obvious must, but I’d also like the architecture to accommodate pulsed and variable modes so I can toggle them on in future updates without a full rewrite.

While the underlying equation and method are fully finalized, the exact implementation details will only be shared after an NDA is in place. For bidding purposes, assume an initial single-screen MVP with:

• One numeric input field (meters)
• Display of computed base frequency (Hz)
• Toggle to show either octave ladder or φ-based ladder
• Tap-to-play for any listed frequency
• Start/Stop control for playback
• Output routing to device speaker or Bluetooth audio (when available)

Flutter or React Native are acceptable as long as the final builds pass App Store and Google Play review. Native Swift/Kotlin implementations are equally acceptable if you believe they offer superior timing precision — if so, state why.

Acceptance criteria

• End-to-end audio latency from tap to sound ≤ 50 ms on current flagship phones
• Frequency accuracy within ±1 Hz across the 20–2000 Hz MVP range
• Clean, well-structured source delivered in a private Git repo
• TestFlight build (iOS) and internal testing APK (Android) provided for validation
• Architecture must allow future support for replacing sine tones with custom audio assets without rewriting core logic

If this is in your comfort zone, let’s talk and move this from spec to prototype now." (client-provided description)