NodeMCU ESP8266 + DS18B20 need help

Community Help With My Project
1

Hi,

First steps and need some help. From serial monitor I get : “vw 1 temp,c=%.3f”

My code:

#define CAYENNE_DEBUG
#define CAYENNE_PRINT Serial
#include <ESP8266WiFi.h>
#include "CayenneDefines.h"
#include "BlynkSimpleEsp8266.h"
#include "CayenneWiFiClient.h"
 
#include <OneWire.h>
#include <DallasTemperature.h>
#define VIRTUAL_PIN V1
const int tmpPin = 0;
OneWire oneWire(tmpPin);
DallasTemperature sensors(&oneWire);
 
// WiFi network info.
char token[] = "token";
// Your network name and password.
char ssid[] = "ssid";
char wifiPassword[] = "pass";
 
void setup() {
  Serial.begin(115200);
  Cayenne.begin(token, ssid, wifiPassword);
  sensors.begin();
}
 
void loop() {
  Cayenne.run();
  // do something
}
 
// This function is called when the Cayenne widget requests data for the Virtual Pin.
CAYENNE_OUT(VIRTUAL_PIN)
{
  // Send the command to get temperatures.
  sensors.requestTemperatures();
  // This command writes the temperature in Celsius to the Virtual Pin.
  Cayenne.celsiusWrite(VIRTUAL_PIN, sensors.getTempCByIndex(0));
  // To send the temperature in Fahrenheit use the corresponding code below.
  //Cayenne.fahrenheitWrite(VIRTUAL_PIN, sensors.getTempFByIndex(0));
}
 
 
CAYENNE_CONNECTED()
{
  CAYENNE_LOG("Connection established");
}

I use resistor for DS18B20.

2

Welcome to Cayenne!

Are you getting any values on the dashboard, or nothing at all?

3

On the web it shows minus, on mobile 0.00

4

I believe Celsius / Fahrenheit . write currently doesn’t work on arduino. You have to use virtual,write still, this is the code that’s working for me

CAYENNE_OUT(V1)
{
  // Send the command to get temperatures.
  sensors.requestTemperatures();
  // This command writes the temperature in Celsius to the Virtual Pin.
  Cayenne.virtualWrite(VIRTUAL_PIN, sensors.getTempCByIndex(0));
  // To send the temperature in Fahrenheit use the corresponding code below.
  //Cayenne.fahrenheitWrite(VIRTUAL_PIN, sensors.getTempFByIndex(0));
}
3 Likes
5

Thanks! It works.

For everyone to try (for copy/paste) Celsius values for two parallel DS18B20 (NodeMCU D3 (GPIO0)):

#define CAYENNE_DEBUG
#define CAYENNE_PRINT Serial
#include <ESP8266WiFi.h>
#include "CayenneDefines.h"
#include "BlynkSimpleEsp8266.h"
#include "CayenneWiFiClient.h"

#include <OneWire.h>
#include <DallasTemperature.h>
#define VIRTUAL_PIN1 V1
#define VIRTUAL_PIN2 V2
const int tmpPin = 0;
OneWire oneWire(tmpPin);
DallasTemperature sensors(&oneWire);

//const int tmpPin1 = 1;
//OneWire oneWire1(tmpPin1);
//DallasTemperature sensors1(&oneWire1);

// WiFi network info.
char token[] = "token";
// Your network name and password.
char ssid[] = "ssid";
char wifiPassword[] = "pass";

void setup() {
  Serial.begin(115200);
  Cayenne.begin(token, ssid, wifiPassword);
  sensors.begin();
}

void loop() {
  Cayenne.run();
  // do something
}

// This function is called when the Cayenne widget requests data for the Virtual Pin.
CAYENNE_OUT(V1)
{
  // Send the command to get temperatures.
  sensors.requestTemperatures();
  // This command writes the temperature in Celsius to the Virtual Pin.
  //Cayenne.virtualWrite(VIRTUAL_PIN, sensors.getTempCByIndex(0));
  // To send the temperature in Fahrenheit use the corresponding code below.
  Cayenne.virtualWrite(VIRTUAL_PIN1, sensors.getTempFByIndex(0));
}

CAYENNE_OUT(V2)
{
  // Send the command to get temperatures.
  sensors.requestTemperatures();
  // This command writes the temperature in Celsius to the Virtual Pin.
  //Cayenne.virtualWrite(VIRTUAL_PIN, sensors.getTempCByIndex(0));
  // To send the temperature in Fahrenheit use the corresponding code below.
  Cayenne.virtualWrite(VIRTUAL_PIN2, sensors.getTempFByIndex(1));
}


CAYENNE_CONNECTED()
{
  CAYENNE_LOG("Connection established");
}

To get correct values in Celsius, I had to get Fahrenheit value in NodeMCU and set Celsius in widget. To get correct Fahrenheit in widget, you should change F to C:

Cayenne.virtualWrite(VIRTUAL_PIN1, sensors.getTempFByIndex(0));

to: Cayenne.virtualWrite(VIRTUAL_PIN1, sensors.getTempCByIndex(0));
2 Likes
6

Hi

I used the codes above and I am getting the C info on my Cayenne dashboard as F. I am not sure what I am doing wrong, would appreciate any hep here.

My code:

#define CAYENNE_DEBUG
#define CAYENNE_PRINT Serial
#include <ESP8266WiFi.h>
#include "CayenneDefines.h"
#include "BlynkSimpleEsp8266.h"
#include "CayenneWiFiClient.h"
 
#include <OneWire.h>
#include <DallasTemperature.h>
#define VIRTUAL_PIN V1
const int tmpPin = 0;
OneWire oneWire(tmpPin);
DallasTemperature sensors(&oneWire);
 
// Cayenne authentication token. This should be obtained from the Cayenne Dashboard.
char token[] = "token";
// Your network name and password.
char ssid[] = "ssid";
char password[] = "pass";
 
void setup() {
  Serial.begin(115200);
  Cayenne.begin(token, ssid, password);
  sensors.begin();
}
 
void loop() {
  Cayenne.run();
  // do something
}
 
// This function is called when the Cayenne widget requests data for the Virtual Pin.
CAYENNE_OUT(V1)
{
  // Send the command to get temperatures.
  sensors.requestTemperatures();
  // This command writes the temperature in Celsius to the Virtual Pin.
  Cayenne.virtualWrite(V1, sensors.getTempCByIndex(0));
  // To send the temperature in Fahrenheit use the corresponding code below.
  //Cayenne.fahrenheitWrite(VIRTUAL_PIN, sensors.getTempFByIndex(0));

}
 
 
CAYENNE_CONNECTED()
{
  CAYENNE_LOG("Connection established");
}

And my dashboard:

7

Read the end of my last post. F in code = C in widget and vice versa.