Project

# Title Team Members TA Documents Sponsor
49 Eco-Trim: Smart Scratch Pad Recovery System
 Lehan Pan
Tianyi Xu
Zhizheng Ju
Zihan Wang
 design_document1.pdf
final_paper1.docx
final_paper2.docx
proposal1.pdf
**Team Members:** Zhizheng Ju (zju4), Tianyi Xu (tianyi25), Lehan Pan (lehanp2), Zihan Wang (zihan20)

### Project Description

**Problem**
University libraries generate massive paper waste from partially used or single-sided prints. This innovation aims to reclaim these blank spaces locally, avoiding resource-heavy chemical recycling. The system must autonomously feed discarded stacks, identify blank areas, and extract usable scratch pads.

**Solution Overview**
Eco-Trim is an automated mechatronic system. Unlike standard shredders that destroy paper, or industrial recyclers that require wet pulping, our dry, localized approach actively salvages usable sections. The complexity lies in synchronizing optical detection with mechanical actuation, which is highly feasible given our interdisciplinary team. An ECE-driven solution is absolutely necessary because the system requires a custom PCB, a microcontroller running a finite state machine (FSM), and opto-isolated motor drivers to process sensor data and execute high-torque cutting safely.The entire system operates with a single push of a button, strictly adhering to the one-button activation rule.

**Components**
* **Mechanical Feeding:** Motorized friction rollers engineered to ensure reliable single-sheet feeding and flattening without jamming.
* **Optical Detection:** A custom PCB integrating an MCU and optical contrast sensors to scan and map printed versus blank areas.
* **Cutting Actuation:** A stepper-motor-driven blade mechanism designed for precise, automated trimming based on sensor feedback.
* **Safety Interlocks (Critical):** Essential IR light curtains and enclosure limit switches that instantly sever high-voltage motor power upon detecting human proximity, preventing injury and ensuring safe public usability.

**Criteria of Success**
1. System continuously feeds at least 5 single sheets of paper without mechanical jamming.
2. Optical sensors correctly differentiate printed from blank areas, triggering the appropriate cutting logic.
3. The actuation blade cleanly severs the paper into uniform pads without tearing.
4. Hardware safety interlocks physically disconnect motor power within 100ms when the enclosure is opened or the light curtain is breached.

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