Classroom People Counter

About this project

Build a doorway-mounted headcount system that tells you exactly how many people are inside a classroom, lab, or study room right now — without any camera, app, or WiFi. Two HC-SR04 ultrasonic sensors are mounted side by side across a doorway threshold. Whoever passes triggers the outer sensor first then the inner one when entering, and the reverse order when exiting — the Arduino compares the two timestamps to work out direction and adjusts a live headcount shown on a 16x2 LCD. Set a room capacity limit and the buzzer sounds automatically the moment it's exceeded. The WOW moment: stand at the door, walk in, watch the LCD count go up by exactly one — walk out, watch it go down. Build time: 2-3 hours. Fully offline, no WiFi, no app, no cloud.

What you get

• Complete, commented source code
• Full components list with quantities
• Pin-by-pin wiring guide and connection table
• Step-by-step upload and testing guide
• Project report (.docx, IEEE style)
• Presentation slides (.pptx)