Smart Waste Segregator with Dry and Wet Sorting

Source segregation is the single biggest bottleneck in municipal waste handling: mixed waste reaches processing plants because segregation at the bin depends on every user remembering the rules every time. Dry waste contaminated with wet waste loses recycling value, and wet waste mixed with plastic cannot be composted properly. This project attacks the problem at the point of disposal with a tabletop segregator: the user drops waste into one hopper, a capacitive soil-moisture-style sensor measures the item's moisture content as it passes the sensing chamber, and an Arduino classifies it as dry or wet and swings a servo flap to route it into the correct bin. An IR break-beam sensor counts each item and the LCD keeps running totals. The build demonstrates the complete sense–decide–actuate loop — capacitive sensing, threshold classification, servo control and event counting — on hardware a student can fully explain.

1. Waste is dropped into the single hopper; the IR break-beam sensor at the mouth detects the item and wakes the sensing sequence.
2. The item rests briefly in the sensing chamber against the capacitive moisture sensor plate.
3. The Arduino samples the sensor (typically 10 readings averaged) and compares the value against the calibrated dry/wet threshold.
4. Based on the classification, the servo flap swings to the dry-bin or wet-bin position; a short delay lets the item fall through.
5. The flap returns to neutral, the LCD counters increment, and the system arms for the next item.
6. Items that fall in the ambiguous band around the threshold are routed to a default side and flagged on the LCD, so the student can demonstrate the edge case honestly.
7. The threshold is set during calibration: the student records readings for known dry and known wet samples and picks the midpoint, documented in the calibration log.

Tech stack:

• Arduino Uno (ATmega328P)
• Capacitive moisture sensor module
• IR break-beam / proximity sensor
• High-torque servo motor (flap diverter)
• 16×2 character LCD
• Twin collection bins with sensing chamber
• Arduino IDE (C/C++ firmware)

• [Capacitive moisture sensing] A capacitive sensor measures each item's moisture content in the sensing chamber — no contact corrosion issues, since the electrode never touches the waste directly through the chamber wall.
• [Automatic dry/wet classification] The Arduino compares the reading against a student-calibrated threshold and classifies the item as dry or wet within about a second of sensing (design target).
• [Servo flap diverter] A high-torque servo swings the sorting flap to route each item into the dry bin or the wet bin, then returns to neutral for the next item.
• [IR item detection] An IR break-beam sensor at the hopper mouth detects each dropped item, wakes the sensing sequence and increments the total count.
• [Live sort counters] A 16×2 LCD shows running counts of dry, wet and total items sorted, plus the current system state.
• [Student calibration procedure] The moisture threshold is set by the student using sample dry and wet items, with the procedure and a calibration log sheet included — so the classification boundary is measured, not guessed.
• [Twin-bin output] Two removable bins collect the segregated streams, ready to demonstrate handover to recycling and composting flows.

• Working prototype: hopper, sensing chamber, servo flap, twin bins, sensor set
• Complete firmware (sensing, classification, actuation, counting)
• Moisture-threshold calibration procedure with log sheet
• Wiring diagram and mechanical assembly guide
• Project report PDF (background, capacitive sensing theory, methodology, calibration results)
• PPT presentation for final review
• Viva Q&A preparation document