hello! I can not work by PWM

[HanSeoHyun]

hello! I want to use nodeMCU esp8266 12E, and MH_Z19B sensor by PWM but, It does not work. help me please...

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include

include "MHZ19.h"

//const int rx_pin = 13; //Serial rx pin no //const int tx_pin = 15; //Serial tx pin no const int pwmpin = 14; //MHZ19 mhz19_uart = new MHZ19(rx_pin,tx_pin); MHZ19 mhz19_pwm = new MHZ19(pwmpin);

/---------------------------------------------------------- MH-Z19 CO2 sensor setup ----------------------------------------------------------/ void setup() { Serial.begin(115200); mhz19_pwm -> begin(pwmpin); // mhz19_uart->begin(rx_pin, tx_pin); mhz19_pwm->setAutoCalibration(false); while (mhz19_pwm->isWarming()) { Serial.print("MH-Z19 now warming up... status:"); Serial.println(mhz19_pwm->getStatus()); delay(1000); } }

/---------------------------------------------------------- MH-Z19 CO2 sensor loop ----------------------------------------------------------/ void loop() { int co2ppm = mhz19_pwm->getPPM(MHZ19_POTOCOL::PWM); int temp = mhz19_pwm->getTemperature();

//Serial.print("co2: ");
//Serial.println(co2ppm);
//Serial.print("temp: ");
//Serial.println(temp);

co2ppm = mhz19_pwm->getPPM(MHZ19_POTOCOL::PWM);
Serial.print("co2: ");
Serial.println(co2ppm);

delay(5000);

}

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sensor-----nodeMCU PWM-----D5 GND-----GND Vin------Vin

error: can't get MH-Z19 response. MH-Z19 now warming up... status:error: can't get MH-Z19 response. -1

that messages are show infinite....

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I tested my nodeMCU by another code, And I tested my sensor by UNO. They works well.

How can I work well...? Help me please.....

[crisap94]

Would you mind retry again with the new example, the library just had a refactor.

[MagTun]

I uploaded the MHZ19_getppm.ino sketch to my nodeMCU esp8266 and used the same connection as mentionned above:

sensor-----nodeMCU
   PWM-----D5
   GND-----GND
   Vin-----Vu

and I am still getting the same error:

MH-Z19 now warming up...  status:error: can't get MH-Z19 response.
-1

Any idea how to solve this?