Mesh Emergency Chat App Performance

ISEF Category: Systems Software

Subcategory: Mobile Apps  ·  Difficulty: Advanced  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

When a school network fails, phones can still talk to each other nearby. That means an app could pass urgent messages room to room without cell service or Wi-Fi. Your job is to find out how fast, reliable, and secure that kind of system really is. That makes this a real test of emergency communication, not just app design.

What Is It?

This project studies a mesh chat app, which lets phones relay messages through nearby devices instead of sending everything through a central server. Think of it like a human chain in a hallway. If one person cannot reach the next person directly, a message can still travel by hopping across the group.

Your app concept combines Bluetooth and Wi-Fi-Aware, which help nearby phones discover each other and exchange data. Store-and-forward routing means a phone can hold a message until it finds the next available phone. End-to-end encryption means only the sender and receiver can read the message, even if other phones help carry it.

Why This Is a Good Topic

This is a strong science fair topic because you can measure real performance data, not just build an app that works in theory. You can test latency, delivery rate, packet loss, battery use, and how crowd size changes the results. The project connects to school safety, disaster response, and offline communication, which gives it real-world value. You can also learn app design, networking basics, encryption, and data analysis from one project.

Research Questions

• How does classroom crowd size affect message delivery latency in a Bluetooth and Wi-Fi-Aware mesh chat app?
• What is the effect of hop count on message delivery success in a store-and-forward routing system?
• Does encrypting messages change delivery time or battery use compared with unencrypted messages?
• To what extent does phone placement in the room affect message reach and latency?
• Which routing rule gives the best balance of speed and delivery rate in a 30-phone classroom test?
• How does message size affect success rate and delay in a peer-to-peer school emergency chat app?

Basic Materials

• Android phones with Bluetooth and Wi-Fi-Aware support, ideally 10 to 30 devices.
• One classroom or similar indoor test space.
• Android Studio installed on a development laptop.
• USB cables for app testing and charging.
• Stopwatch or screen-recording tool for timing checks.
• Spreadsheet software for logging latency, delivery rate, and device positions.
• Printed room map or floor plan for placing devices.
• Tape or sticky notes for marking phone locations.

Advanced Materials

• Android phones with developer mode enabled and Wi-Fi-Aware support.
• Laptop with Android Studio and logcat access.
• Local test server or logging endpoint for collecting event traces.
• Packet capture or network diagnostic tools approved for Android testing.
• Battery monitoring tools or external USB power meters.
• Encryption library for Android app development.
• Statistical analysis software for comparing routing conditions.
• Image or layout software for mapping device positions and hop paths.

Software & Tools

• Android Studio: Builds and tests the Android app on real devices.
• Logcat: Captures connection events, routing events, and delivery timestamps.
• ImageJ: Measures phone spacing and room layout from images or floor plans.
• Python: Cleans log files and calculates latency, success rate, and summary graphs.
• LibreOffice Calc: Organizes trial data and makes quick plots without paid software.

Experiment Steps

1. Define the one network behavior you will measure first, such as delivery latency, delivery success rate, or battery use.
2. Choose a classroom layout and decide how you will place phones so each trial starts the same way.
3. Set up a control condition, such as direct nearby transfer, so you can compare the mesh path against a simpler baseline.
4. Plan the routing variables you will change, such as crowd size, hop count, or message size.
5. Build a data log that records sender, receiver, time sent, time received, and whether the message arrived intact.
6. Decide in advance how you will compare encryption and routing choices using graphs and statistical tests.

Common Pitfalls

• Testing only one classroom layout, which hides how much the mesh changes when phones move.
• Forgetting a baseline comparison, which makes it hard to tell whether the mesh helps more than direct transfer.
• Mixing up Wi-Fi-Aware discovery limits with routing failures, which can make the app look slower than it really is.
• Measuring only the first delivery, which ignores how repeated messages behave when devices get busy.
• Skipping device model tracking, which can blur performance differences between newer and older phones.

What Makes This Competitive

A stronger project goes past a demo and becomes a careful systems study. You can stand out by comparing several routing strategies, testing more than one room layout, and separating discovery delay from true message delivery delay. Good visualizations help too, especially if you map how message paths change as the classroom gets denser or more fragmented. If you also test security overhead, you show that you understand both safety and performance.

Project Variations

• Test the same mesh app in a hallway, gym, or cafeteria to see how building shape changes delivery behavior.
• Compare Bluetooth-only routing against Bluetooth plus Wi-Fi-Aware to isolate which link layer helps more.
• Measure whether short emergency alerts travel faster and more reliably than longer status messages.
• Compare encrypted and unencrypted message paths to see how security changes latency and battery use.

Learn More

• Android Developers Nearby: Official docs for Bluetooth and Wi-Fi-Aware features, found on the Android Developers site.
• Android Developers Wi-Fi Aware: API documentation for peer discovery and data transfer, found on the Android Developers site.
• NIST Cryptographic Standards and Guidelines: Free guidance on encryption basics and approved methods, found on the NIST site.
• PubMed: Search for review articles on delay-tolerant networking, mobile ad hoc networks, and emergency communication.
• IEEE Xplore or ACM Digital Library: Search for peer-reviewed papers on mobile mesh routing and offline messaging systems.
• MIT OpenCourseWare Computer Science courses: Free networking and systems materials that help you understand routing and packet delivery.