Volume Panel: Custom Styles

Inspiration

Most audio customization apps focus on sound but ignore the experience of controlling it. We wanted to give users not just audio clarity but also a beautiful, personalized volume panel. After seeing how dull system sliders were, we set out to make volume control both useful and delightful. We do not have most of the devices, but this app lets us enjoy different device Volume Styles. We specifically liked the Pixel 9 and NothingOS UI.

What it does

Volume Panel: Custom Style reimagines the phone’s volume UI. Users can:

Switch between multiple styled panels (Material You, iOS, One UI, and more).
NothingOS style lets the user access Media Player in Volume Panel
User Customization, Slider background, Slider fill color, Panel Position, Slider length, Corner Radius, Slider Spacing, Slider width.
In settings, we provided different theme options: System theme, Dark, and Light theme.
We have six different slider options for the user: Media Volume, Ring Volume, Alarm Volume, Call Volume, Notification Volume, and System Volume.
It lets the user control Volume Panel timeout, Haptic feedback, Play sound, and Dim the background on volume change.
Unlock premium features via RevenueCat lifetime upgrades.
Test new designs for 24 hours through rewarded ads.
Enjoy an ad-free experience after the upgrade.
Receive OneSignal smart notifications prompting reviews and ratings.

How we built it

Frontend: Android (Kotlin + Jetpack Compose + Material 3) for a modern, responsive UI.
Monetization: RevenueCat SDK for lifetime unlocks and Google AdMob for Ads revenue stream.
Growth: AdMob for free tier monetization + rewarded ads; OneSignal for targeted notifications.
Analytics: Firebase + in-app metrics to track installs, DAU, and upgrades.
AI Assistance: Google Gemini for coding scaffolding; manual intervention for unique UI panels. Below is one of the first prompts we use to feed the Gemini coding agent.
You are Senior Android Developer. Use the current Android app project and create: - Kotlin + Jetpack Compose (Material 3 expressive), minSdk 26+, target latest. - MVVM with Hilt DI, Navigation Compose, Kotlin Coroutines/Flows. - Add a :app module only (monolith). - Add DataStore(Preferences) for settings. Provide a SettingsRepository with typed getters/setters. - Compose theme: Material 3 “expressive” (large type scale, dynamic color, motion), edge-to-edge, dark/light support. - Create a baseline UI: Home screen with large FAB “Volume Style”. - Prepare foreground service skeleton with MediaStyle notification. No logic yet. - Manifest: Add POST_NOTIFICATIONS (runtime) for Android 13+ when starting the service. - Handel app permission gracefully, ask user to give permission first. - Add unit/instrumentation test setup, proguard/r8 configs for release. - Provide compile, run, and request-permission flows. Deliver: full project files with comments, and a README.md explaining structure and how to run.

This first prompt helps set the basic requirements for the app; we used Perplexity AI for the full plan. For this, we always provide basic ideas, features, and usage of the app that we want to build, then we provide some of the other Google Play Store links of a few apps in this niche. Apparently, Perplexity is really good at extracting data from a website.

Design: Every volume style required unique UI coding, not just template duplication.
App icon and App Screenshot: App screenshot was created using a combination of Figma and Gemini nano banana (first screenshot with hand). For the app Icon, we found this prompt works very well for us, so we used it for all of our apps.

Prompt: A professional high-quality photo of the [above shared image], made of plasticine on a pure white background, product photography, realistic, front view, close-up, art project, crafts, sculpture, minimalist style, medium detail, 4k
[above shared image] - We combined some of the sliders from Volume Control Panel UI and fed it with a prompt.

Challenges we ran into

We assumed we could build one panel template and reuse it across styles. Instead, each style had unique quirks that required separate, hand-coded UIs. This slowed development but gave us deeper control. RevenueCat integration also required careful testing to align rewarded ads with lifetime unlock logic.

Accomplishments that we're proud of

1,000+ downloads in <2 weeks, with ~20% active users.
- We currently have a 30% conversion rate on the Play Store listing
5 premium purchases already - early but promising.
Strong user reviews after OneSignal-driven campaigns.
Delivered smooth lifetime unlock flow with RevenueCat.
Built in a short timeline as a 2-person indie team.

Honestly we never thought of getting this much coverage in less then two week without any Ad campaign, we have been publish app for the last 1 year. One of our Equalizer applications took 2.5 months to receive this much attention.

App Store Optimization (ASO) from Perplexity helped here. So we first used Perplexity Deep Research to generate a strategy with the current updated requirements and best practices, then we proceeded by providing our application description. Afterward, we provided some of the links to applications in this niche so that LLM can extract the best keywords and generate optimized titles, Short descriptions, and long descriptions.

What we learned

Monetization works best when users get immediate visible value (unlock styles), hence we used an Ad reward.
Rewarded ads let users “try before they buy,” creating organic upgrade motivation.
Each UI style is a product in itself—personalization needs detail, not shortcuts.
Combining ads + lifetime premium is sustainable for both casual and power users, hence two revenue streams.
Most importantly, we explored a lot of prompts and how to best use them for both App Store Optimization (ASO) and getting started with a trivial yet important part of the App coding with Gemini.
One of the important things, when we were developing all 4 apps in such a short time, we created a lot of templates. Like About Us screen, RevenueCat template, OneSignal template, AdMob template. This helped to focus on the core of the application.

What's next for Volume Panel: Custom Styles

App-specific volume presets (e.g., auto-set Spotify volume when opened).
4+ new panel styles currently in development.
Themed UI packs (brand-based, movie-inspired, custom packs).
Scaling monetization: premium packs, bundled unlocks.
Longer-term: Model Context Protocol (MCP) for Android - project—users create custom volume Styles (tools for each UI control) via natural language [our pet project :)].

We sincerely thank all the judges for taking the time to review our application. In addition, we’ve built three more Android apps for this hackathon—please take a moment to explore them as well.

We crunched day and night to build four Android apps during this hackathon, and we learned a lot about how to use coding agents to our advantage. Winning would help us finally expand into marketing, where we’ve been lacking. Thank you, judges.

Our Google Play Developer Page -