TESA · Alang Babega

TESA unit outdoors: a box labelled 'Automatic handsanitizer dispenser with thermometer' with a blue LCD screen — The TESA dispenser unit

How it works

Register on the TESA web app and get a personal QR code.
Show the QR code to the camera on the device.
After a beep, put your hand under it.
It sprays sanitizer, checks your temperature, and logs your attendance.
If your temperature is above 37.5 °C or below 34 °C, it beeps and shows "access denied".

What I built

Device: an Arduino Nano reads an MLX90614 infrared thermometer and an HC-SR04 ultrasonic sensor (for hand detection), drives a pump for the sanitizer, and shows results on an I2C LCD
Brain: a Raspberry Pi 3B with a camera scans QR codes using OpenCV and PyZBar, asks the Arduino for a temperature over serial, and saves the check-in to Firebase
Web app (TESA): React + Firebase, for registering, getting your QR code, and viewing your check-in history
Installer: a one-line curl script that sets up the Pi software as a system service

QR code ─▶ Pi camera ─▶ Raspberry Pi ─serial─▶ Arduino Nano
                             │                  ├ thermometer
                             ▼                  ├ hand sensor
                          Firebase              ├ pump
                             ▲                  └ LCD
                     TESA web app

Gallery

Circuit schematic: Arduino Nano with GY-906 temperature sensor, HC-SR04 ultrasonic sensor, I2C LCD, buzzer, and a pump switched by a 2N2222 transistor — Device schematic (from my earlier Autothermonitizer build)

Flowchart: detect QR code or hand, read temperature, spray sanitizer, display temperature, and alert if outside 34 to 37.5 °C — Device logic: QR check-in, temperature check, sanitizer spray

TERA web app login screen with email and password fields — TERA app: login

TERA web app dashboard showing user info, a personal QR code, and recent activities — TERA app: personal QR code for check-in