Project

# Title Team Members TA Documents Sponsor
12 Automatic Solder Fume Extractor Positioning System
 Franklin Liu
Noah Zhang
Yubo Wu
 Pusong Li design_document1.pdf
proposal1.pdf
# Automatic Solder Fume Extractor Positioning System

Team Members:
- Yubo Wu (yubowu2)
- Noah Zhang (noah7)
- Franklin Liu (fl26)

# Problem

Local fume extractors used during hand soldering must be positioned close to the active soldering location to effectively capture fumes. When working across larger circuit boards or repositioning a workpiece, the extraction hood may need to be repeatedly moved. This interrupts the soldering workflow and can result in the hood being left too far from the active soldering area.

# Solution

We propose a motorized fume extractor arm that automatically positions the extraction hood near the active soldering location.

A thermal sensor mounted near the extraction hood will detect the heated soldering iron and determine its position relative to the center of the extraction region. A microcontroller will use this information to control a two-link planar arm and follow the soldering iron across the work surface.

The planar arm will use an existing SCARA-style mechanical design as the basis for its structure, modified to support the extraction hood and sensing hardware. The entire planar arm will also move vertically using a motorized linear axis. A distance sensor mounted near the hood will measure the distance to the work surface, allowing the system to maintain a desired extraction height automatically. A commercially available fume extractor will provide airflow through a lightweight flexible hose connected to the moving hood.

# Solution Components

## Subsystem 1: Thermal and Distance Tracking
A Melexis MLX90640ESF-BAB-000-TU 32 × 24 thermal sensor array will be mounted near the extraction hood and directed toward the work surface. The thermal image will be processed by the microcontroller to identify the heated soldering iron and determine its displacement from the desired extraction location.

A VL53L1X time-of-flight distance sensor will measure the distance between the extraction hood and the work surface. This measurement will be used to control the vertical position of the hood.

## Subsystem 2: Motorized SCARA Arm
The extraction hood will be mounted to a two-link planar SCARA-style arm with two powered rotary joints. The mechanical structure will be adapted from an existing open-source SCARA arm design.

The two planar joints will be driven by NEMA 17 stepper motors. The entire planar arm will be mounted on a motorized vertical linear stage driven by a third stepper motor and lead screw. Three D2F-01L-A microswitches will provide home-position references for the two planar joints and vertical axis.

The arm links, sensor mounts, and extraction hood mounting components will be 3D printed. A lightweight flexible hose will connect the moving hood to the fume extractor.

## Subsystem 3: Control and Power PCB

A custom PCB will control the sensing and motion systems. The board will contain:

- ESP32-S3-WROOM-1 microcontroller
- Three TMC2209-LA stepper motor driver circuits
- Interfaces for the MLX90640 thermal sensor and VL53L1X distance sensor
- Interfaces for the three D2F-01L-A home-position sensors
- 12 V DC power input and motor power distribution
- Voltage regulation for low-voltage logic
- Hardware emergency-stop circuitry that disables the motor drivers

# Criterion For Success
- The thermal sensing system will correctly detect a heated soldering iron within the defined tracking region in at least 90% of test cases.
- The planar arm will automatically move the extraction hood to keep the detected soldering iron within a predefined central region over the designed workspace.
- The system will maintain the extraction hood within a horizontal and vertical distance from the soldering location that is experimentally demonstrated to provide effective fume capture.
- The vertical positioning system will automatically maintain the extraction hood within a predefined distance range from work surfaces at multiple tested heights.
- Activating the hardware emergency stop will disable all three motor axes independently of the microcontroller software.

# Stretch Goals
- Automatically control the fume extractor based on whether active soldering is detected.
- Adjust extractor airflow based on the distance between the hood and the soldering location.

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