LifeLink

Smart health-safety bracelet that protects health,
detects falls and automatically calls for help

Student Company · School year 2025/26

Team:	LIFE LINK - WRISTBAND FOR VULNERABLE PATIENTS
Members:	Kristina Gocev Teodora Pejčić Luka Vučić Mihailo Pešić Sava Petrović
Class:	IV-1
School:	Tehnička škola Pirot
Teacher-Mentor:	Boban Blagojević, B.Sc. in Electrical Engineering
Business Mentor:	Sanja Rančić, B.Sc. in Economics
School Year:	2025 / 2026

Junior Achievement Serbia – Student Company Program | Regional Competition 2025

1

Executive Summary

3

Platforms

7

Components

5s

Alert Reaction

2G

GSM Autonomy

🎯 Mission

Provide elderly and the most vulnerable patients with an autonomous safety mechanism embedded in a smart health-safety bracelet, eliminating the need for a smartphone to send emergency responses.

👁 Vision

Become the standard healthcare safety solution through affordable embedded technology — combining biometrics, IMU sensors, and GSM communication.

Product: LifeLink is a smart health-safety bracelet based on the ESP32-S3 microcontroller with a 466×466px AMOLED screen that autonomously monitors vital signs, detects falls via a 3-phase algorithm, and sends an SMS containing GPS location via the built-in SIM800L GSM module – all without requiring a smartphone.

Financial Summary: The prototype hardware investment amounts to ~8,500 RSD per unit. The projected retail price is established at 15,000 RSD. Gross margin per unit: ~43%.

2

Company Overview

Company Purpose: LifeLink was created to solve a pressing, real-world issue – elderly individuals (>20% of the Serbian population) are highly vulnerable to falls, the leading cause of bodily injuries in this demographic. Available market solutions (e.g., Apple Watch, imported medical alerts) are either excessively expensive or require continuous smartphone dependency. LifeLink offers an affordable, standalone alternative.

Idea Origin & Development: The idea stemmed from the realization that current smartwatches and wearable devices are overly complex and tied to smartphone ecosystems. The team asked: "Can life-saving protection be embedded into an affordable standalone device?" The answer was found within open-architecture embedded systems.

Current Status:

Fully functional hardware prototype
Completed ESP32-S3 firmware (ESP-IDF)
Cross-platform Flutter mobile app
Company presentation website

Problem Being Solved:

Delayed reaction to falls in the elderly
Requirement to carry an additional phone for SOS
Prohibitive cost of commercial alternatives
Lack of locally tailored support options

Overall strategy and goals: Initial focus is placed on the local market segment for the elderly. Short-term goal: prototyping and initial regional sales. Long-term goal: official medical IoT device certification and mass manufacturing scalability.

3

Product

The LifeLink smart health-safety bracelet integrates three main functional systems into one small wearable form factor:

System	Technology	Competitive Advantage
Fall Detection (3-Phase)	QMI8658 IMU + SVM algorithm	Eliminates false alarms (θ > 60° orientation + 5s immobility guard)
Health Monitoring	MAX30102 optical sensor + FFT	Hardware-accelerated real-time FFT frequency mapping (100 Hz)
GSM SOS (Autonomous)	SIM800L + UART AT Commands	Operates WITHOUT a phone, sends SMS with Google Maps GPS link

📉 Free Fall
SVM < 0.6g

→

💥 Impact
SVM > 3.5g / 500ms

→

⏱ Immobility
5 seconds + θ > 60°

→

📲 SMS Alert
GPS + BPM

💰 Pricing Strategy

Cost of components: ~8,500 RSD. Set retail price: 15,000 RSD. Method: cost-plus formulation and comparative tier analysis of existing market IoT wearables.

🚀 Innovation

LifeLink is currently the only solution on the local market merging 3-phase fall detection, vital readings, and pure hardware GSM SOS without a mobile app required – positioned within an affordable segment.

4

Business Operations

Production & Delivery Plan:

Procurement from global & local electronics distributors
Manual hardware assembly and soldering of initial prototypes
Firmware flashing and board configuration using ESP-IDF toolchain
Sensor calibration and quality control testing pre-delivery
Packaging: protective case + user manual + firmware update link

Costs & Investment:

Item	RSD
ESP32-S3 AMOLED Core Board	5,500
SIM800L GSM Module	800
MAX30102 Optics	400
Capacitors, Cabling, Tools	600
Prepaid SIM + Activation	300
Packaging and Printing	400
TOTAL (per unit)	8,000

Margin: ~7,000 RSD/unit (47%)

5

Market & Marketing Strategy

Market Analysis:

Primary target group: Elderly individuals (65+), people with chronic illnesses, caregivers
Segment size: ~1.5 million people 65+ in Serbia
Geographic focus: Pirot municipality (local), National (online sales funnel)
Needs assessment: Conducted field interviews with caregivers concerning elders living independently

Competitor Positioning:

Solution	Price	Autonomy
Apple Watch	~70,000 RSD	❌ Needs iPhone
Life Alert / Medical Imports	~30,000 RSD	✅
LifeLink	15,000 RSD	✅ Standalone

Marketing Channels: Presentation Website School Exhibitions Local Health Institutes Social Media Word of Mouth

Unique Selling Proposition (USP): Standalone GSM operation without expensive hardware or subscriptions, optimized locally. An added value stream lies in the companion Flutter mobile app offered for free to caregivers requiring continuous BLE/remote monitoring.

6

Sales & Promotion

Sales Strategy:

Direct sales at educational and tech fairs
Demonstrations at elderly care centers and polyclinics
E-commerce endpoint (lifelink-watch.github.io)
Offering live demonstration trials to potential caregiver families

Sales Goals and Projections:

Period	Goal (units)
Q1 (Oct – Dec)	2 – beta testers
Q2 (Jan – Mar)	5 – exhibitions/fairs
Q3 (Apr – Jun)	8 – direct sales conversions
Annual Target	15 units

Achieved: [X units] | Revenue: [X RSD]

7

Management / Operations

CEO – Team Director
Kristina Gocev

Hardware & Firmware
Mihailo Pešić

Finances
Luka Vučić

Mobile App

Sales & Marketing

Communication Channels:

Weekly sync meetings (Google Meet / Physical)
Git repository for strictly versioned source code (GitHub)
Centralized Google Drive for business documentation

Engineering Challenges Faced:

GSM module peak 2A current instability → Resolved via dedicated decoupling capacitors
Fall detection false positives → Resolved by replacing threshold logic with a 3-phase algorithm & geometric angle checks
Synchronizing FreeRTOS dual-core tasks around LVGL UI rendering

8

Overall Impression & Business Profitability

The LifeLink team evaluates the business year as technically exceptionally successful, while navigating standard startup challenges in customer acquisition and scaling.

Key Pivotal Decisions:

Migrating from GA6-B to SIM800L – Enhanced power stability and full spectrum network coverage
Direct Battery Supply – Circumventing boost converters removed severe voltage dropout issues
Software Auto-Recovery – Added watchdog timers ensuring system resilience
Introduction of Flutter App – Greatly expanded the total addressable market footprint

Cost Structure (Per Unit Basis):

Item	RSD
Fixed Costs Coverage (Tools)	2,000
Variable Component Cost	8,000
Retail Price	15,000
Gross Margin/Unit	7,000 (47%)
Net Profit/Unit	5,000 (33%)

Break-even point: 1 unit sold successfully covers fixed prototyping expenses. Capital reserves will be reinvested into 3D printer filament and SLA molds for future production iterations.

9

Future Prospects

Investment Potential:

Global CAGR of health wearables consistently exceeds 15%
Serbia's aging demographic trends present a continuous domestic market need
Transitioning to AI-driven TinyML data classification for algorithmic infallibility
Potential B2B integrations involving AWS IoT or Firebase health dashboards

R&D Roadmap:

🏠 Custom CAD-modeled, 3D printed water-resistant casing
😴 Enhanced ESP32 Deep Sleep optimizations extending operating life to 3+ days
🧠 TinyML neural networks (Edge Impulse) replacing mathematical thresholds
📡 Direct hardware GPS (LC76G I²C) bypassing triangulation inaccuracies
🏥 Formal pilot programs launched via local healthcare clinics

Long-term Survival Strategy: Partnering with regional gerontological centers, forming a subscription tier for unlimited SIM connectivity/support, and potentially licensing the detection algorithm IP to mass-market smartwatch vendors.

10

Financial Overview

Income Statement (School Yr. 2025/26)

Description	RSD
Sales Revenue ([X] units)	[X × 15,000]
Material Costs	[X × 8,000]
Fixed Operating Expenses	2,000
Administrative Expenses	500
Net Earnings	[Amount RSD]

Balance Sheet (As of [Date])

Assets	RSD
Cash and Cash Equivalents	[Amount]
Inventory (Parts & WIP)	[Amount]
Capital Assets (Equipment)	2,000
Total Assets	[Total]

Liabilities & Equity	RSD
Owner Investments	[Amount]
Retained Earnings	[Amount]
Total Equity	[Total]

11

Teacher-Mentor's Report

The student company LifeLink emerged directly as a result of genuine curiosity and the drive of class IV-1 students attempting to engineer an innovative solution for a universally relatable problem. As their mentor overseeing the complete lifecycle of their development, I state unequivocally that the team demonstrated a level of technical depth and sheer perseverance extending far beyond what's typically expected at the secondary educational level.

The team independently conquered vastly complex programming paradigms – shifting from elementary coding to rigorous ESP-IDF embedded engineering involving FreeRTOS multiprocessing logic, applying DSP analytics (FFT) for optical biometric decoding, up to deploying cross-platform architectures natively in Flutter. The students' technical troubleshooting processes – especially resolving severe hardware power grid issues regarding GSM modules – showcased a remarkable methodological maturity, relying heavily upon official schematics and experimental verification over guesswork.

Execution of this product equipped the students not solely with hard-engineering proficiency but amplified their capacity toward collaborative grit, business administration, budgeting logic, and strategic ideation. LifeLink serves as a premier testament to how the modern classroom functions successfully as an incubator for pragmatic, community-benefitting technological innovation.

Boban Blagojević, B.Sc. in Electrical Engineering
Professor of Electrical Subjects, Tehnička škola Pirot

✓

Conclusion

3-Phase

Fall Detection Logic

100%

GSM Operation

3+

Software Platforms

47%

Gross Unit Margin

LifeLink operates as an industrially viable prototype offering robust empirical proof that student entrepreneurs possess the capability to build commercially targeted, technically sophisticated solutions. The culmination of zero dependency standalone cellular capabilities, state machine-based fall filtering algorithms, alongside an accessible economic proposition establishes LifeLink as an exceptional candidate slated for broader market development and commercial distribution.

References & Literature

[1] Espressif – ESP-IDF Framework and FreeRTOS Docs – docs.espressif.com
[2] LVGL – Light and Versatile Graphics Library – lvgl.io
[3] SIMCom – SIM800L AT Commands Manual and Hardware Design
[4] QST Corporation – QMI8658C IMU Datasheet
[5] Maxim Integrated – MAX30102 Pulse Oximeter Datasheet
[6] Google Developers – Maps URL API Documentation – developers.google.com/maps
[7] Flutter / Dart SDK Documentation – flutter.dev
[8] Espressif ESP-DSP Library – DSP algorithms for ESP32 – github.com/espressif/esp-dsp

LifeLink Student Company · Tehnička škola Pirot · Regional Competition JA Serbia 2025/26 · Page 6 of 6