Saathi

Inspiration: An Urgent Need in an Unseen Market

The statistics surrounding personal safety are staggering: globally, 1 in 3 women experience violence, and in India, a crime against a woman was registered every 71 seconds in 2024. The current personal safety wearable market presents families with a narrow, flawed set of options. Handing a child a smartphone exposes them to the open internet too early, while premium wearables introduce structural problems: strict dependency on a paired Bluetooth phone, expensive monthly subscriptions ($10–$30/month), and reactive panic buttons that must be pressed during an emergency. Furthermore, clinical trackers often sit in a drawer. Saathi was inspired by the idea that safety should not be a luxury subscription. The goal is to build a protective device disguised as an everyday gift—a keychain, pendant, or bag clip—that is affordable for tier-2 and tier-3 Indian households.

What It Does & The "Safe Game" Failsafe

Saathi is a standalone, AI-assisted safety wearable that operates without a paired smartphone and requires zero subscriptions.

• Proactive Analysis: Uses on-device motion sensors to proactively detect the physical impact of a fall or the erratic signature of a struggle, bypassing the need for a reactive panic button.

• Standalone Connectivity: Operates via an onboard cellular SIM to guarantee complete independence from smartphone range limits.

• Three-Tier Response: Triggers a "Safe Game" failsafe that auto-dials family with live audio, forwards official GPS coordinates to India's 112 (ERSS), and pings a Community Grid of verified responders within a 500m radius.

Architecture & Hardware Challenges

Transitioning from software development to embedded hardware introduces significant constraints. The primary challenge is filtering out false-positive alerts while strictly maintaining a low target BOM (estimated at Rs. 930–980 for the Phase 1 prototype).

• Core Hardware: The Phase 1 prototype relies on an ESP32-C3 for deep-sleep power management, an MPU6050 for 6-axis motion tracking, and a SIM800L for robust 2G/GSM rural connectivity.

• Geospatial Logic: The backend calculates the great-circle distance between the wearer and local responders using the Haversine formula: $$ \vartheta=2r\cdot \arcsin\left(\sqrt{\sin^{2}\left(\frac{\varphi_{2}-\varphi_{1}}{2}\right)+\cos(\varphi_{1})\cos(\varphi_{2})\sin^{2}\left(\frac{\lambda_{2}-\lambda_{1}}{2}\right)}\right) $$

• Power Optimization: To preserve battery life in a tiny form factor, the ESP32 is woken by the MPU6050's interrupt pin only upon detecting a physical trigger.

What's Next: Proving the Concept & Civic Alignment

The roadmap moves Saathi from a breadboard prototype to a reliable, compliant safety network.

• Phase 1 (Validate): Extensively field-test the algorithmic thresholds against simulated falls to tune out false positives.

• Phase 2 (Miniaturize): Design a custom PCB incorporating a SIP module and an FPC antenna, deploying a pilot run of 100–300 units in semi-urban test beds like Rooma and Chakeri.

• Phase 3 (Scale & Civic Mandates): Onboard local security guards by leveraging the Private Security Agencies Regulation Act (PSARA)—which legally mandates emergency response training—and coordinate directly with India's 112 Emergency Response Support System (ERSS) and local Public Safety Answering Points (PSAPs) to institutionalize rapid intervention across communities.

Built With

• idea