Case Study · Hackathon, 1st Place · Research

SentinelEdge

Privacy-first, on-device scam detection for live phone calls — built in a single day, now the basis of a paper submitted to EMNLP 2026.

Result · 🥇 1st Place, AI Tooling Track Event · Claude Builder Club Hackathon @ ASU, March 2026 Stack · On-device SLM, federated learning

Overview

Built in a single day at the Claude Builder Club Hackathon at ASU, SentinelEdge is a privacy-first, on-device scam detection system for live phone calls. It won 1st place in the AI Tooling track, and the underlying approach is now the basis of a paper submitted to EMNLP 2026.

Problem

The people most vulnerable to phone scams are often the least equipped with technical defenses — and most existing scam-detection approaches require sending call data to the cloud, a privacy tradeoff that's a non-starter for many of the users who need protection most.

Business Context

Built for a hackathon track judged on real-world AI tooling, differentiated specifically on the privacy-first, on-device constraint rather than raw model accuracy — a deliberate positioning bet that paid off in the judging.

Architecture

Live call audio is analyzed entirely on-device by a compressed, fine-tuned small language model, with periodic federated learning updates improving the model over time — no raw call data ever leaves the device.

Live call audio
Captured on-device; never transmitted off the phone.
On-device transcript analysis
Compressed, fine-tuned small language model runs locally.
Scam-likelihood scoring
Real-time risk score computed on-device.
User alert
Surfaces the warning to the user in real time.
Federated learning update
Model improves over time without raw data ever leaving the device.

Tech Stack

On-device small language modelFederated learningReal-time transcript analysis

Tradeoffs

The core tradeoff: on-device, privacy-preserving inference over a larger cloud-hosted model — accepting some ceiling on raw accuracy and model size in exchange for zero data leaving the device. Given the target users, that's a deliberate and well-argued tradeoff, not a limitation to apologize for.

Lessons Learned

Privacy constraints aren't just a compliance checkbox — here, they were the actual design driver that made the product usable by the people who needed it most. Designing for the constraint first, rather than retrofitting privacy onto a cloud-first design, shaped every other decision in the build.

Research / EMNLP

The on-device detection approach from SentinelEdge has been developed into a paper submitted to EMNLP 2026. Full abstract and link will be added once the paper is public.

Interview Story

Situation
A one-day AI hackathon, tackling phone scam detection for a population with the least technical defenses.
Task
Build real-time scam detection without any data ever leaving the user's device.
Action
Built and fine-tuned a compressed small language model for on-device transcript analysis with federated learning updates. [add your specific piece of the team build]
Result
Won 1st place in the AI Tooling track; the approach is now the basis of a paper submitted to EMNLP 2026.