PIR Sensor for Workshop Dust Collection

Project Overview

This project creates an automatic dust collection system for your workshop. When you approach a power tool (table saw, miter saw, router table), a PIR sensor detects your presence and turns on the dust collector. After you leave, the system runs for a short delay to clear remaining dust, then shuts off automatically.

Difficulty: Intermediate
Estimated time: 2-3 hours
Estimated cost: $25-35

How It Works

A PIR sensor mounted near each power tool detects when you approach. When motion is detected, the ESP32 activates a relay that turns on the dust collector. A timer keeps the collector running for 30-60 seconds after the last motion to clear residual dust. Multiple sensors can control a single dust collector from multiple tools.

Materials Needed

• ESP32 or Arduino (1)
• HC-SR501 PIR sensors (1-4)
• Relay module (5V, rated for dust collector motor current)
• Power supply (5V 2A)
• Jumper wires
• Project enclosure
• Wire and conduit for sensor wiring

Circuit Diagram

Connection Table

OUT

GPIO 4

OUT

GPIO 5

OUT

GPIO 6

IN

GPIO 7

Anode

GPIO 2

表

Arduino Code

// Automatic Dust Collection System
const int numSensors = 3;
const int sensorPins[] = {4, 5, 6};
const int relayPin = 7;
const int ledPin = 2;

unsigned long lastMotionTime = 0;
const unsigned long runAfterDelay = 60000;
bool dustCollectorOn = false;

void setup() {
  Serial.begin(115200);
  
  for (int i = 0; i < numSensors; i++) pinMode(sensorPins[i], INPUT);
  pinMode(relayPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  
  digitalWrite(relayPin, LOW);
  digitalWrite(ledPin, LOW);
  
  delay(60000);
}

void turnOnDustCollector() {
  if (!dustCollectorOn) {
    digitalWrite(relayPin, HIGH);
    digitalWrite(ledPin, HIGH);
    dustCollectorOn = true;
  }
}

void turnOffDustCollector() {
  if (dustCollectorOn) {
    digitalWrite(relayPin, LOW);
    digitalWrite(ledPin, LOW);
    dustCollectorOn = false;
  }
}

void loop() {
  bool anyMotion = false;
  
  for (int i = 0; i < numSensors; i++) {
    if (digitalRead(sensorPins[i]) == HIGH) anyMotion = true;
  }
  
  if (anyMotion) {
    lastMotionTime = millis();
    turnOnDustCollector();
  }
  
  if (dustCollectorOn && (millis() - lastMotionTime > runAfterDelay)) {
    turnOffDustCollector();
  }
  
  delay(100);
}

Installation Steps

1. Assemble main control box near dust collector
2. Run 3-conductor wire from each sensor to control box
3. Mount sensors near each power tool at chest height
4. Wire dust collector motor through relay
5. Connect 5V power supply
6. Approach each tool to test collector activation

Project Extensions

• Use ESP-NOW for wireless sensors
• Add current sensor to detect when tool is actually running
• Add servo-controlled blast gates for suction routing
• Add particulate sensor to automatically run collector
• Add Wi-Fi to monitor dust collector runtime

Conclusion

This automatic dust collection system makes woodworking cleaner and more convenient, saving energy and reducing noise.