App Overview

Signal Lights icon

Signal Lights

Jose Tomy Joseph · Entertainment

Turn your iPhone or iPad into a working traffic signal.

$1.99

PRICE
$1.99
No in-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
3.9
9 ratings · Top 50%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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Build Kit

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A product spec, screen plans, and build steps for your coding agent.

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Combine features and design from your favorite apps.

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What's included14 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Signal Lights: map the core Entertainment workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Offer more pre-set patterns and user-defined settings.

Assumption to check: Limited customization options for light patterns

Validate with people who use this workflow before building.

Hypothesis 2

Optimize for lower-end devices to improve user experience.

Assumption to check: Inconsistent performance on older devices

Validate with people who use this workflow before building.

Hypothesis 3

Add a review and feedback feature to engage users.

Assumption to check: Lack of user feedback options

Validate with people who use this workflow before building.

Hypothesis 4

Allow users to share their custom patterns on social media.

Assumption to check: No social sharing features

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

Turn your iPhone or iPad into a working traffic signal. Signal Lights runs a real signal cycle on your screen, at whatever timings you set. Prop it up next to a play mat and it directs toy cars. Stand it on a desk and it teaches a child what amber actually means. Hold it up at a campsite gate or a classroom door and it does a job. CHOOSE THE SIGNAL YOU KNOW Signals are not the same everywhere. Some show red and amber together before green, as a get-ready; others go straight from red to green. Both are built in, along with a pedestrian crossing, a flashing amber for caution, and a simple stop-and-go with no amber at all. Pick whichever matches the signal outside your window — you will see it running as a small preview before you choose. SET YOUR OWN TIMINGS Every phase can be adjusted, and each signal remembers what you set. Change your mind and one tap restores the standard timings. TWO WAYS TO RUN IT Automatic runs the cycle on a timer, like a real signal. Manual waits for you — tap to change the light yourself, which is what you want when you are directing people rather than simulating traffic. BUILT TO BE SEEN In portrait you get the full signal head with the countdown inside it. Turn the phone sideways and the lit lamp fills the screen, large enough to read across a hall or a car park. The screen stays awake while the signal runs, and you can dim the app without touching your phone's own brightness. MADE TO BE READABLE BY EVERYONE A colour-blind-safe palette replaces red and green with tones that stay distinct, and turns on lamp names so the signal never depends on colour alone. An outdoor mode brightens everything for use in daylight. VoiceOver announces each change as it happens. PRIVATE BY DESIGN Signal Lights asks for no permissions. It does not use the camera, the microphone, Bluetooth or your local network, and it never connects to the internet. There are no accounts, no advertising, no analytics and no tracking of any kind. Nothing you do in the app leaves your device. It works exactly the same in aeroplane mode. — Signal Lights is a simulator and a teaching tool. It is not a traffic control device and must never be used to direct vehicles or people on public roads.

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
React Native
Expo
react-navigation
expo-color-picker
@react-native-async-storage/async-storage
Zustand
BUILD KIT DIFFICULTY
Starter

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.