Arduino Dust Sensor
Put together a Arduino-based dust sensor over the weekend using the following components:
- Arduino Mega 2560
- Shinyei PPD42NS dust sensor
- LCD Shield (16 x 2)
The codes and wiring instructions for Arduino Mega 2560 and Shinyei PPD42NS is as follow. However, I did include Serial output so you can view the sampling results using Arduino IDE’s Serial Monitor (9600 bauds).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | /**********************************************/ /* Building Arduino Dust Sensor using: */ /* - Arduino Mega 2560 */ /* - Shinyei PPD42NS */ /* http://www.sca-shinyei.com/pdf/PPD42NS.pdf */ /* */ /* Author: shadowandy[dot]sg[at]gmail[dot]com */ /* Web: www.shadowandy.net */ /* */ /* Wiring Instruction: */ /* - PPD42NS Pin 1 => GND */ /* - PPD42NS Pin 2 => D51 */ /* - PPD42NS Pin 3 => 5V */ /* - PPD42NS Pin 4 => D50 */ /**********************************************/ #include <LiquidCrystal.h> LiquidCrystal lcd(8, 13, 9, 4, 5, 6, 7); byte nano[8] = {B00000,B00000,B00000,B10010,B10010,B10010,B11110,B10000}; byte pow3[8] = {B11000,B00100,B11000,B00100,B11000,B00000,B00000,B00000}; #include <avr/wdt.h> #define PM25 0 #define PM10 1 int pin[] = {50,51}; unsigned long starttime; unsigned long sampletime_ms = 30000; unsigned long triggerOn[2]; unsigned long triggerOff[2]; unsigned long lowpulseoccupancy[] = {0,0}; float ratio[] = {0,0}; float count[] = {0,0}; boolean value[] = {HIGH,HIGH}; boolean trigger[] = {false, false}; void setup() { lcd.createChar(0,nano); lcd.createChar(1,pow3); lcd.begin(16, 2); Serial.begin(9600); //Output to Serial at 9600 baud pinMode(pin[PM25],INPUT); //Listen at the designated PIN wdt_enable(WDTO_8S); starttime = millis(); //Fetching the current time } void loop() { value[PM25] = digitalRead(pin[PM25]); value[PM10] = digitalRead(pin[PM10]); if(value[PM25] == LOW && trigger[PM25] == false) { trigger[PM25] = true; triggerOn[PM25] = micros(); } if(value[PM25] == HIGH && trigger[PM25] == true) { triggerOff[PM25] = micros(); lowpulseoccupancy[PM25] += (triggerOff[PM25] - triggerOn[PM25]); trigger[PM25] = false; } if(value[PM10] == LOW && trigger[PM10] == false) { trigger[PM10] = true; triggerOn[PM10] = micros(); } if(value[PM10] == HIGH && trigger[PM10] == true) { triggerOff[PM10] = micros(); lowpulseoccupancy[PM10] += (triggerOff[PM10] - triggerOn[PM10]); trigger[PM10] = false; } wdt_reset(); if ((millis()-starttime) > sampletime_ms)//Checking if it is time to sample { ratio[PM25] = lowpulseoccupancy[PM25]/(sampletime_ms*10.0); count[PM25] = 1.1*pow(ratio[PM25],3)-3.8*pow(ratio[PM25],2)+520*ratio[PM25]+0.62; ratio[PM10] = lowpulseoccupancy[PM10]/(sampletime_ms*10.0); count[PM10] = 1.1*pow(ratio[PM10],3)-3.8*pow(ratio[PM10],2)+520*ratio[PM10]+0.62; count[PM25] -= count[PM10]; // Begin mass concentration calculation float concentration[] = {0,0}; double pi = 3.14159; double density = 1.65*pow(10,12); double K = 3531.5; // PM10 double r10 = 2.6*pow(10,-6); double vol10 = (4/3)*pi*pow(r10,3); double mass10 = density*vol10; concentration[PM10] = (count[PM10])*K*mass10; // PM2.5 double r25 = 0.44*pow(10,-6); double vol25 = (4/3)*pi*pow(r25,3); double mass25 = density*vol25; concentration[PM25] = (count[PM25])*K*mass25; // End of mass concentration calculation // Begin printing to Serial Serial.print("PM10 : "); Serial.print(concentration[PM10]); Serial.println(" ug/m3"); Serial.print("PM10 Count : "); Serial.print(count[PM10]); Serial.println(" pt/cf"); Serial.print("PM2.5 : "); Serial.print(concentration[PM25]); Serial.println(" ug/m3"); Serial.print("PM2.5 Count: "); Serial.print(count[PM25]); Serial.println(" pt/cf"); Serial.println(""); // Begin printing to LCD lcd.clear(); lcd.print("10 : "); lcd.print(concentration[PM10]); lcd.setCursor(11,0); lcd.write(byte(0)); lcd.print("g/m"); lcd.write(byte(1)); lcd.setCursor(0,1); lcd.print("2.5: "); lcd.print(concentration[PM25]); lcd.setCursor(11,1); lcd.write(byte(0)); lcd.print("g/m"); lcd.write(byte(1)); // Resetting for next sampling lowpulseoccupancy[PM25] = 0; lowpulseoccupancy[PM10] = 0; starttime = millis(); wdt_reset(); } } |
Miscellaneous
With the PM2.5 and PM10 concentration level, we can determine the respective Pollutant Standards Index (PSI) level. The above table is from this document on Calculation of Pollutant Standards Index (PSI).
Hey shadowandy, thanks for your work. Where I can buy the Aruduino Dust Sensor?
Ashish,
Thanks. You can get the dust sensor from http://www.aliexpress.com. It is like eBay.
Hi,
Could you provide some explanations for mass concentration calculation?
For example why density = 1.65 ?
What is K = 3531.5?
It will be very helpfull to understant how to swith between pcs/ml to mg/m3
Thanks in advance.
Hello! Thanks a lot for sharing this nice project! My result are a little low..and i get a lot of zeros..
Anyway, in this interesting blog -indiaairquality.com- there is an interesting solution..add a fan and a resistor between pin5 and ground.. (i think that for ground it takes pin1?).
Thanks again!
Stefano
HI, I plug in your code but using Uno R3. It seems the data fluctuate too much. I cross check with the SDS018 sensor, it is much stable. For eg, PM10 can’t just go from 15.22 to 0.20 then 33.36 again in your data captured. it is too much i think
I think is because the Shinyei PPD42NS is not as accurate (in terms of particle counting) compared to the SDS018 as the latter is laser based. I actually try to do a average over a time period to normalise the readings.
Hi andy thx for ur reply.
I read articles about adding fan n resistor to ppn42ns to get a data closer to benchmark data. But i think for now i will stick to my sds018 to make a dust duino. 😉
Another nice sensor is the PMS1003. I remember reading that it is a good counter too. 🙂
Hi,
With 10k resistor (PIN5 to GND on the sensor) your code works nicely.
I have one question though.
I can see you have pinMode(pin[PM25],INPUT); in the setup, but what about PM10?
Something like:
pinMode(pin[PM25],INPUT);
pinMode(pin[PM10],INPUT);
Thanks
Alex
Alex,
Glad to know that tying 10K resistor works better.
For the pinMode, I think you can add in the PM10 declaration, I may have missed out that line when copying the codes over.
Thanks for the tutorial.
I applied the same code with 10k resistor to ground on PIN5 (sensor).
Instead pin 50 and 51 on Mega2560, i have used PIN 40 & 41.
But no variation in the values of the sensor output. The output always seems like below:
PM10 : 0.20 ug/m3
PM10 Count : 0.62 pt/cf
PM2.5 : 0.00 ug/m3
PM2.5 Count: 0.00 pt/cf
Your reply will be appreciated.