Grove - Dust Sensor

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Introduction

This Dust Sensor measures the Particulate Matter level in air by counting the Lo Pulse Occupancy time(LPO time) in given time unit. LPO time is in proportion to PM concentration. This sensor can provide you pretty reliable data for air purifier system because it's still responsive to particulates whose diameter is 1um. Note: This sensor use counting method to test dust concentration but not weight method, and the unit it pcs/L or pcs/0.01cf.


400px-Dust sensor.jpg

Features

Highly responsive Reliable ROHS/PEACH compliant Note: New version updates output Hi Voltage from Approx. over 4.0V change to Approx over 4.5V. Application Ideas

Dust emission monitor Air Quality Monitoring Cautions

Please keep it upright. 3 min preheat time is required when used at the first time. Arbitrary operation may cause unexpected damage. Pins VR1 and VR2 come preset. Please DON'T change the default configuration.

Specification

Items Min Norm Max Unit VCC 4.75 - 5.25 V Standby Current Supply - 90 - mA Detectable range of concentration - 0~28,000 / 0 ~ 8000 - pcs/liter / pcs/0.01cf Operating Temperature Range 0 - 45 °C Output Method Negative Logic, Digital output,Hi over 4.0V(Rev.2) Lo: under 0.7V Detecting the particle diameter >1 um Dimensions 59(W) × 45(H) × 22(D) [mm] Humidity Range 95%rh or less

Usage

Here is a demo to show you how to obtain PM concentration data from this Grove - Dust Sensor. 1. Plug the dust sensor into digital port D8 on the Grove - Base Shield. It can only be D8, because the operation of this sensor involves sampling, a function only can be achieved by D8, the capture input pin of Atmage328P, on Arduino/Seeeduino. Also you can connect Grove - Dust sensor to Arduino UNO without Base Shield : Arduino UNO Dust Sensor 5V Red wire GND Black wire Digit 8 Yellow wire

2. Copy and paste the demo code below to a new Arduino sketch. /* Grove - Dust Sensor Demo v1.0

Interface to Shinyei Model PPD42NS Particle Sensor
Program by Christopher Nafis 
Written April 2012

http://www.simgin-chip.com/depot/grove-dust-sensor-p-1050.html
http://www.simgin-chip.com/pdf/PPD42NS.pdf

JST Pin 1 (Black Wire)  => Arduino GND
JST Pin 3 (Red wire)    => Arduino 5VDC
JST Pin 4 (Yellow wire) => Arduino Digital Pin 8
*/

int pin = 8; unsigned long duration; unsigned long starttime; unsigned long sampletime_ms = 30000;//sampe 30s ; unsigned long lowpulseoccupancy = 0; float ratio = 0; float concentration = 0;

void setup() {

 Serial.begin(9600);
 pinMode(8,INPUT);
 starttime = millis();//get the current time;

}

void loop() {

 duration = pulseIn(pin, LOW);
 lowpulseoccupancy = lowpulseoccupancy+duration;
 if ((millis()-starttime) > sampletime_ms)//if the sampel time == 30s
 {
   ratio = lowpulseoccupancy/(sampletime_ms*10.0);  // Integer percentage 0=>100
   concentration = 1.1*pow(ratio,3)-3.8*pow(ratio,2)+520*ratio+0.62; // using spec sheet curve
   Serial.print("concentration = ");
   Serial.print(concentration);
   Serial.println(" pcs/0.01cf");
   Serial.println("\n");
   lowpulseoccupancy = 0;
   starttime = millis();
 }

} In this program, the seeeduino samples the total duration of "logic low" in 30s, and this duration illustrates the dust density of environment. Open serial monitor, we can read air quality's value detected by sensor from pc serial port.

Dust sensor 1.png

The result above consists of three parts: lowpulseoccupancy, ratio and concentration. "lowpulseoccupancy" represents the Lo Pulse Occupancy Time(LPO Time) detected in given 30s. Its unit is microsecond. "ratio" reflects on which level LPO Time takes up the whole sample time. "concentration" is a figure that has physical meaning. It's calculated from the characteristic graph below by using the LPO time.


550px-Characteristics.jpg



File:Grove - Dust sensor.pdf