I tried to make an air quality measurement station. It contains an lcd display, sensors for temperature, humidity, brightness, co2 and dust. It is based on an Arduino Nano.
However, the CO2 senesor works in a single script just for the sensor but not in the whole project. It always says "!Error: Timed out waiting for response".
Is it possible that the Arduino gets confused with the different baudrates? I have two times 9600 for the dust and co2 sensor aswell as 115200 for the serial. If so, is there a way to fix it in the code?
Here is the code that works:
#include <Arduino.h>
#include "MHZ19.h"
#include <SoftwareSerial.h> // Remove if using HardwareSerial
#define RX_PIN 3 // Rx pin which the MHZ19 Tx pin is attached to
#define TX_PIN 2 // Tx pin which the MHZ19 Rx pin is attached to
#define BAUDRATE 9600 // Device to MH-Z19 Serial baudrate (should not be changed)
MHZ19 myMHZ19; // Constructor for library
SoftwareSerial mySerial(RX_PIN, TX_PIN); // (Uno example) create device to MH-Z19 serial
unsigned long getDataTimer = 0;
void setup()
{
Serial.begin(9600); // Device to serial monitor feedback
mySerial.begin(BAUDRATE); // (Uno example) device to MH-Z19 serial start
myMHZ19.begin(mySerial); // *Serial(Stream) refence must be passed to library begin().
myMHZ19.autoCalibration(); // Turn auto calibration ON (OFF autoCalibration(false))
}
void loop()
{
if (millis() - getDataTimer >= 2000)
{
int CO2;
/* note: getCO2() default is command "CO2 Unlimited". This returns the correct CO2 reading even
if below background CO2 levels or above range (useful to validate sensor). You can use the
usual documented command with getCO2(false) */
CO2 = myMHZ19.getCO2(); // Request CO2 (as ppm)
Serial.print("CO2 (ppm): ");
Serial.println(CO2);
int8_t Temp;
Temp = myMHZ19.getTemperature(); // Request Temperature (as Celsius)
Serial.print("Temperature (C): ");
Serial.println(Temp);
getDataTimer = millis();
}
}
And here the whole project where the CO2 sensor doesnt work anymore:
#include <Arduino.h>
//Display
#include <Adafruit_GFX.h> // Core graphics library
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735
#include <SPI.h>
#include <Wire.h>
#define TFT_CS 7 // Chip Select P7
#define TFT_DC 4 // RS nur pins D1-D4 P6
#define TFT_RST 8 //Nano: D8 D1 mini: D6 // Reset P5
// #define TFT_MOSI D7 //Nano: D11 D1 mini: D7 // Data out MOSI / SDA P4
// #define TFT_SCLK D5 //Nano: D13 d1 mini: D5 // Clock out SCK / SPI P3
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);
// For ST7735-based displays, we will use this call
// Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);
//Luxmeter
#include <BH1750.h>
BH1750 lightMeter;
//SHT31 Temperature
#include <SHT31.h>
#define SHT31_ADDRESS 0x44
SHT31 sht;
float Tempr, Humd;
uint32_t start;
uint32_t stop;
//PMS
#include <SoftwareSerial.h>
#include <PMS.h>
SoftwareSerial pmsSerial(5, 6);
PMS pms(pmsSerial);
PMS::DATA data;
//CO2
#include "MHZ19.h"
#define RX_PIN 3 // Rx pin which the MHZ19 Tx pin is attached to
#define TX_PIN 2 // Tx pin which the MHZ19 Rx pin is attached to
#define BAUDRATE 9600 // Device to MH-Z19 Serial baudrate (should not be changed)
MHZ19 myMHZ19; // Constructor for library
SoftwareSerial mySerial(RX_PIN, TX_PIN); // (Uno example) create device to MH-Z19 serial
unsigned long getDataTimer = 0;
int CO2;
void setup(void) {
Serial.begin(115200);
Wire.begin();
//Display
tft.initR(INITR_BLACKTAB); // Init ST7735S chip, black tab
tft.fillScreen(ST77XX_BLACK);
tft.setRotation(1);
//Luxmeter
lightMeter.begin();
//SHT31 Temperature
sht.begin(SHT31_ADDRESS);
uint16_t stat = sht.readStatus();
//CO2
mySerial.begin(BAUDRATE); // (Uno example) device to MH-Z19 serial start
myMHZ19.begin(mySerial); // *Serial(Stream) refence must be passed to library begin().
myMHZ19.autoCalibration(); // Turn auto calibration ON (OFF autoCalibration(false))
//PMS
pmsSerial.begin(9600);
Wire.setClock(100000);
}
void loop() {
if (pms.read(data))
{
Serial.print("PM 1.0 (ug/m3): ");
Serial.println(data.PM_AE_UG_1_0);
Serial.print("PM 2.5 (ug/m3): ");
Serial.println(data.PM_AE_UG_2_5);
Serial.print("PM 10.0 (ug/m3): ");
Serial.println(data.PM_AE_UG_10_0);
//CO2
if (millis() - getDataTimer >= 2000)
{
CO2 = myMHZ19.getCO2(); // Request CO2 (as ppm)
Serial.print("CO2 (ppm): ");
Serial.println(CO2);
int8_t Temp;
Temp = myMHZ19.getTemperature(); // Request Temperature (as Celsius)
Serial.print("Temperature (C): ");
Serial.println(Temp);
getDataTimer = millis();
}
//SHT31 Temperature
start = micros();
sht.read(); // default = true/fast slow = false
stop = micros();
Serial.print("T:");
Serial.print(sht.getTemperature(), 1);
Serial.print("H:");
Serial.println(sht.getHumidity(), 1);
Tempr = sht.getTemperature();
Humd = sht.getHumidity();
//Luxmeter
float lux = lightMeter.readLightLevel();
Serial.print("Light: ");
Serial.print(lux);
Serial.println(" lx");
}
}
