36 HOURS NATIONAL LEVEL HACKATHON - New Prince Shri Bhavani College + IEEE + IETE
MediGuard
An embedded IoT system that monitors storage temperature of
critical medicines in real-time — with smart alerts, LED profiles,
and cloud logging via Google Sheets.
Controller
ESP32
Sensor
DHT11
Display
I2C LCD 16×2
Cloud
Google Sheets + Apps Script
Alert
Buzzer + Email
Simulated live reading
24.3°C
INSULIN — SAFE ✓
// 01 — Overview
What is MediGuard?
3
Medicine profiles
selectable by button
≤5s
Alert response
time on breach
24/7
Continuous automated
monitoring
∞
Cloud log history
via Google Sheets

Problem

Temperature-sensitive medicines — vaccines, insulin, blood samples — require precise cold-chain conditions. Manual monitoring in rural clinics causes fluctuations, spoilage, and safety risks. High-cost commercial systems are inaccessible to small healthcare setups.

Solution

MediGuard uses an ESP32 microcontroller with a DHT11 sensor to continuously read storage temperature. A single-button profile selector sets the safe zone. When breached, a buzzer, LED, and email alert fire automatically. All readings are logged to Google Sheets via WiFi.

System Flow

STEP 01
Button Press
Select medicine profile
Red / Blue / Green LED
→
STEP 02
Sensor Read
DHT11 reads temp
every 5 seconds
→
STEP 03
Compare
Temp vs profile
safe limit
→
STEP 04
Alert
Buzzer + LCD
on breach
→
STEP 05
Cloud Log
HTTP POST to
Google Sheets
→
STEP 06
Email Alert
MailApp sends
notification
// 02 — Medicine Profiles
Smart profile
selection
BTN_RED — 1 Press
Insulin
Safe limit: ≤ 20°C
Cold-chain critical.
Requires continuous monitoring
and automatic cooling control.

Red LED active when selected.
BTN_BLUE — 2 Press
Hormone
Safe limit: ≤ 28°C
Moderate cool storage.
Hormone injections and
enzyme kits. Controlled
environment required.

Blue LED active when selected.
BTN_GREEN — 3 Press
Blood
Safe limit: ≤ 45°C
Room-cool monitoring.
Blood samples and diagnostic
reagents. Monitoring required;
heavy cooling not needed.

Green LED active when selected.
2°–8°C
Cold Chain (Critical)
  • Vaccines
  • Insulin
  • Biologic injections
  • Blood samples
  • Diagnostic reagents
8°–15°C
Moderate Cool
  • Antibiotic syrups
  • Hormone injections
  • Enzyme kits
15°–25°C
Room-Cool
  • Tablets & capsules
  • Creams and ointments
  • Saline bottles
// 03 — System Architecture
Hardware → Cloud
pipeline
Sensor
🌡️
DHT11
Reads ambient temperature every 5s. Connected to ESP32 GPIO 4.
→
Controller
⚙️
ESP32
Main logic. Drives LCD, LEDs, buzzer. WiFi for HTTP POST. Button input for profile.
→
Cloud API
☁️
Apps Script
doPost() receives JSON payload. Writes row to sheet. Fires email on alert flag.
→
Storage + Alert
📊
Google Sheets
Timestamp, medicine, temp, limit, status logged per event. Email via MailApp.

Pin Map — ESP32

GPIO 4 → DHT11 Data
GPIO 21/22 → I2C SDA/SCL (LCD)
GPIO 32 → Red LED
GPIO 19 → Blue LED
GPIO 23 → Green LED
GPIO 13 → BTN Red
GPIO 25 → BTN Blue
GPIO 18 → BTN Green
GPIO 33 → Buzzer

Google Sheet Columns

Col A — Timestamp
Col B — Medicine name
Col C — Temperature (°C)
Col D — Safe limit (°C)
Col E — Status (OK / ALERT)
Col F — Alert sent (YES / NO)

// 04 — Live Simulation
Interactive hardware
simulation
ESP32 — MediGuard v1.0
I²C LCD 16×2
Temp:--.-C
--------
DHT11 --.-°C
GPIO 4
Status LEDs
Red
GPIO32
Blue
GPIO19
Green
GPIO23
🔔
Buzzer
GPIO33
SILENT
Profile Buttons
WiFi → Google Sheets
Live temperature readings
Temp
Limit
📊 TempLog — Google Sheets 0 rows logged
Timestamp Medicine Temp °C Limit °C Status Alert
⚠ TEMPERATURE ALERT
—
// 05 — Team
Project team
AMG
A Monica Gandhi
III BE ECE
Electronics & Communication Engineering
Avinashilingam Institute
APG
A Priyanka Gandhi
IV BE ECE
Electronics & Communication Engineering
Avinashilingam Institute
GS
G Swathi
III BE ECE
Electronics & Communication Engineering
Avinashilingam Institute