Tech Arcanist

ThermaLog Gun V2

The ThermaLog Gun V2 is the upgraded version of my original project — [ ThermaLog Gun V1 ]. In this version, an RFID module was integrated along with the contactless temperature sensor to log both the user identity and their body temperature into Google Sheets. Unlike V1 (which used an ESP8266), this version uses the ESP32, offering faster processing, better performance, and more GPIOs for multiple peripherals. This makes it suitable for applications like attendance + temperature screening in offices, labs, schools, or controlled entry points.

Features

  • RFID-Based User Identification: Reads unique user ID using RFID cards/tags.
  • Contactless Temperature Measurement: Uses the MLX90614 infrared sensor to measure body temperature without physical contact.
  • Automated Cloud Logging: ESP32 pushes User ID + Temperature + Timestamp directly to Google Sheets using the Google Sheets API.
  • Wireless & Portable: No PC required — works via Wi-Fi through ESP32.
  • Real-Time Monitoring: Data appears instantly in Google Sheets for analysis or future reference.

Components Used

  • ESP32 — Main microcontroller with Wi-Fi and Bluetooth support
  • MLX90614 (Infrared Temperature Sensor) — Measures body temperature without physical contact
  • RFID RC522 Module — Reads RFID card/tag UID for user identification
  • OLED Display — Displays the scanned user ID and temperature
  • Buzzer + Push Button — Used for feedback and user interaction
  • Google Sheets API — Stores data (RFID UID + Temperature + Timestamp) in the cloud
  • Jumper Wires + Breadboard — Used for wiring and prototyping during the testing phase

How it Works

he ESP32 acts as the brain of the system, continuously gathering data from soil moisture, temperature, humidity, rain, and water tank level sensors. Based on these readings:
  • User taps/scans their RFID card on the RC522 RFID module.
  • ESP32 reads the unique RFID UID.
  • MLX90614 measures the temperature without touching the user.
  • ESP32 uploads the captured data to Google Sheets in the format:
  • → RFID UID + Temperature + Timestamp
  • Data updates in real-time and can be viewed from anywhere.

Current Status (Prototype Tested)

  • RFID scanning + temperature sensing + cloud logging successfully tested on ESP32.
  • The system uploads data properly to Google Sheets.
  • Project was tested only on a breadboard prototype.
  • The project was paused before enclosure and final hardware build due to exams.

Media Availability (Important Note)

This was an old project, and at that time I wasn’t documenting builds properly.
I do not have many photos or videos of this version — only one video of the serial monitor output showing RFID + temperature logging working.

Working

Insta Highlight

Code & Installation

The complete source code is available in the GitHub repository.
View on github ->

My Learnings

  • Interfacing RFID RC522 with ESP32
  • Combining multiple modules (RFID + MLX90614 + OLED)
  • Sending structured data to Google Sheets API
  • Working with APIs, authentication, and cloud logging
  • Managing multiple sensors together on the ESP32 platform