I am trying to read air quality from SDS011 but i am not getting any readings from the sensor. I know that the sensor works fine beacause i have tested it on an RPi. My code is:
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
// most of the code is based on code from www.inovafitness.com and
// www.dfrobot.com
// set the LCD address to 0x2? for a 16 chars and 2 line display
// use a i2c scanner to detect the real address!
LiquidCrystal_I2C lcd(0x21, 20, 4);
long previousMillis = 0;
const int analogInPin = A0;
int latch = 8;
int srclk = 9;
int ser = 10;
unsigned char displayTemp[8];
unsigned int Pm25 = 0;
unsigned int Pm10 = 0;
void ProcessSerialData()
{
uint8_t mData = 0;
uint8_t i = 0;
uint8_t mPkt[10] = {0};
uint8_t mCheck = 0;
while (Serial.available() > 0)
{
// from www.inovafitness.com
// packet format: AA C0 PM25_Low PM25_High PM10_Low PM10_High 0 0 CRC AB
mData = Serial.read();
delay(2);//wait until packet is received
Serial.println(mData);
Serial.println("*");
if (mData == 0xAA) //head1 ok
{
mPkt[0] = mData;
mData = Serial.read();
if (mData == 0xc0) //head2 ok
{
mPkt[1] = mData;
mCheck = 0;
for (i = 0; i < 6; i++) //data recv and crc calc
{
mPkt[i + 2] = Serial.read();
delay(2);
mCheck += mPkt[i + 2];
}
mPkt[8] = Serial.read();
delay(1);
mPkt[9] = Serial.read();
if (mCheck == mPkt[8]) //crc ok
{
Serial.flush();
Serial.write(mPkt, 10);
Pm25 = (uint16_t)mPkt[2] | (uint16_t)(mPkt[3] << 8);
Pm10 = (uint16_t)mPkt[4] | (uint16_t)(mPkt[5] << 8);
if (Pm25 > 9999)
Pm25 = 9999;
if (Pm10 > 9999)
Pm10 = 9999;
Serial.println(Pm25);
Serial.println(Pm10);
//get one good packet
return;
}
}
}
}
}
void setup() {
// lcd.init(); // initialize the lcd
// lcd.backlight();
// Print a message to the LCD.
// lcd.backlight();
Serial1.begin(9600, SERIAL_8N1);
Serial.begin(9600, SERIAL_8N1);
// Serial.begin(9600);
Pm25 = 0;
Pm10 = 0;
}
void loop() {
ProcessSerialData();
// lcd.setCursor(0, 0);
// lcd.print("PM 2.5 -> ");
// lcd.print(float(Pm25) / 10.0);
// lcd.setCursor(0, 1);
// lcd.print("PM 10 -> ");
// lcd.print(float(Pm10) / 10.0);
Serial.println();
Serial.print("Pm2.5 ");
Serial.print(float(Pm25) / 10.0);
Serial.println();// Display();
Serial.print("Pm10 ");
Serial.print(float(Pm10) / 10.0);
Serial.println();
Serial1.println();
Serial1.print("Pm2.5 ");
Serial1.print(float(Pm25) / 10.0);
Serial1.println();// Display();
Serial1.print("Pm10 ");
Serial1.print(float(Pm10) / 10.0);
Serial1.println();
delay(2000);
}
I want to view the readings in my serial monitor, but the only thing i get there is :
Pm2.5 0.00
Pm10 0.00
over and over again..
Can please anyone take a look at this and give me some input if they can find any errors in my code?
I connected the rx (sds011) to tx1 and tx (sds011) to rx1. And 5V --> 5V, GND --> GND
