Blynk + Wemos D1 mini + TMP36

[rav527]

Hello Everyone

My first post on the community and second project with Blynk. I am trying to do a simple setup with wemos d1 mini clone + TMP36 temp sensor + Blynk. I am still learning so please be patient with me

Hardware is connected as such: TMP36 is connected to G pin, 3v3 pin and A0 pin physically on wemos
Blynk is setup for pin under analog A0

Here is the code that I am using

#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h>
#include <OneWire.h>
#include <DallasTemperature.h>
SimpleTimer timer;
#define Pin 0//  pin DATA ds18b20

char auth[] = "AUTH CODE HERE";


OneWire ourWire(Pin); 
DallasTemperature sensors(&ourWire); 

char ssid[] = "WIFI NAME HERE";
char pass[] = "WIFI PASSWORD HERE";

void setup()
{
  Serial.begin(115200);

  Blynk.begin(auth, ssid, pass);
  sensors.begin();
  delay(5000);

  timer.setInterval(2000L, leeTEMP);

}
 
void leeTEMP()
{
  sensors.requestTemperatures();
  Blynk.virtualWrite(0, sensors.getTempCByIndex(0));
}

void loop()
{
  Blynk.run();
  timer.run();
}

[mohan_sundaram]

@rav527 Does it work or not? What help do you need?

[rav527]

The app shows project is not online even though i have the write auth, wifi and password in the code

[mohan_sundaram]

Please post code under the “three back ticks cpp, {paste code} and three back ticks” sequence as I’ve under.

#define BLYNK_PRINT Serial

#include <ESP8266WiFi.h>

#include <BlynkSimpleEsp8266.h>

#include <SimpleTimer.h>

#include <OneWire.h>

#include <DallasTemperature.h>

SimpleTimer timer;

#define Pin 0//  pin DATA ds18b20

char auth[] = “AUTH CODE HERE”;

OneWire ourWire(Pin);

DallasTemperature sensors(&ourWire);

char ssid[] = “WIFI NAME HERE”;

char pass[] = “WIFI PASSWORD HERE”;

void setup()

{

Serial.begin(115200);

Blynk.begin(auth, ssid, pass);

sensors.begin();

delay(5000);

timer.setInterval(2000L, leeTEMP);

}

void leeTEMP()

{

sensors.requestTemperatures();

Blynk.virtualWrite(0, sensors.getTempCByIndex(0));

}

void loop()

{

Blynk.run();

timer.run();

}

What does your serial monitor show? Does it show connecting to Blynk server. Read up connection manage state of your connection. First check fro Wifi connection and then the Blynk server connection.

[rav527]

I will go home n try that in the evening. Let you know my findings. thank you.

[Shadeyman]

Shouldn’t these “ ” be these " " … ?

[mohan_sundaram]

@Shadeyman

Shouldn’t these “ ” be these " " … ?

@Shadeyman Lost you here… Long day and so probably having a jaded brain right now…

[Shadeyman]

@mohan_sundaram

Lost you here

Example: Shouldn’t this

char ssid[] = “WIFI NAME HERE”;

Look like this

char ssid[] = "WIFI NAME HERE";

[mohan_sundaram]

@Shadeyman

Shouldn’t this

char ssid = “WIFI NAME HERE”;

Look like this

char ssid = “WIFI NAME HERE”;

Aah. Now I see… yeah, good catch.

[Gunner]

@rav527 I fixed your code formatting as shown here

[README] Welcome to Blynk Community!

Hey, welcome to Blynk Community. This is the best place to ask questions, leave feedback and share your ideas. If this is the first time you hear about Blynk, check out our website www.blynk.cc and come back! As the community is big (and growing), let’s agree on some basic rules. Asking for help Before creating a new topic and asking for help, please check if your question was already answered: Use forum search function You may want to check out: Blynk Documentation Blynk Wiki Blynk Exa…

and here

[rav527]

Tried this code and it display correct temperature over serial monitor. Now i dont know how to make this code to send data over wifi…i have read the manual in the help section but still at loss at the basics. please help.

int sensorPin = 0;
 
void setup()
{
 Serial.begin(9600);
}
 
void loop()
{
 
 int reading = analogRead(sensorPin); 
 // measure the 3.3v with a meter for an accurate value
 //In particular if your Arduino is USB powered
 float voltage = reading * 3.3; 
 voltage /= 1024.0; 
 
 // now print out the temperature
 float temperatureC = (voltage - 0.5) * 100;
 Serial.print(temperatureC); 
 Serial.println(" degrees C");
 
 delay(1000);
}

[Gunner]

Backticks, not commas for the code formatting

As for your code… Blynk can’t work with too much stuff in the void loop()… You need to use timers.

Look at this example using a couple of different sensors…

C++ Blynk (Legacy) - Code Examples for Basic Tasks

#17 - Dual Temperature Sensors running on ESP-01 This is a simple example of running both a DHTxx (in this case DHT11) and DS18B20 1-wire sensors on the lowly ESP-01 [17][clone_546054541] #include <ESP8266WiFi.h> #include <BlynkSimpleEsp8266.h> #include <ESP8266mDNS.h> // For OTA #include <WiFiUdp.h> // For OTA #include <ArduinoOTA.h> // For OTA char auth[] = "xxxxxxxxxx"; // Local Server char ssid[] = "xxxxxxxxxx"; char pass[] = "xxxxxxxxxx"; //char server[] = "xxx.xxx.xxx.xxx"; // I…

[mohan_sundaram]

This is easily done using the value display widget. Please pick out the value display widget example from the sketch builder, run it and you will understand how it works. Fairly simple. I’m sure you will then be able to integrate it into your project.

Essentially, you need to write that value to a virtual pin using blynk.virtualWrite call. Viola…The widget on the phone tied to the same virtual pin will display the value.

[rav527]

Hi Mohan,

can you please help on how to modify the code that display data over serial and send to blynk. after you show me i will be able to compare both codes and learn from that. i understand its super easy for you but i have to see an example to learn. thank you.

[Gunner]

@rav527

but i have to see an example to learn. thank you.

So perhaps look at the examples? This is just one of many, including the link I sent you above.

Blynk Example Browser

[rav527]

thank you. i didnt know about the example sketch generator. what is virtual pin 5? on my wemos d1 mini i dont have any such pin.

[Gunner]

All the links for the Documentation, Help Center and Sketch Builder are at the top of this page… you may need to scroll up to see them.

@rav527

what is virtual pin 5

here is a link for that info…

http://help.blynk.cc/getting-started-library-auth-token-code-examples/blynk-basics/what-is-virtual-pins

Virtual pins are virtual and are meant to transfer information between the App and the sketch, not part of the physical GPIO.

Note, when programming ESP boards with Arduino IDE you do NOT normally use the silkscreened pin designations, rather you would use the Arduino pin designations.

[rav527]

#define BLYNK_PRINT Serial

#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

char auth[] = "aec5825e0cee4708b9b293f0d8755fae";

char ssid[] = "YYYY";
char pass[] = "XXXXXXX";

BLYNK_READ(V5) //Blynk app has something on V5
{
  sensorData = analogRead(A0); //reading the sensor on A0
  Blynk.virtualWrite(V5, sensorData); //sending to Blynk
}

void setup()
{
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
}

void loop()
{
  Blynk.run();
}

ok so i tried uploading this code after reviewing some of the examples but the code wont upload. its says sensor data was not declared in this scope.

[Gunner]

@rav527

sensor data was not declared in this scope.

@rav527

sensorData =

All variables need to be declared in some way, either within the function where that are used or globally where they can be used throughout the code.

Programming 101…

Using Variables in Sketches | Arduino Documentation

https://www.arduino.cc/reference/en/language/variables/variable-scope--qualifiers/scope/

[rav527]

#define BLYNK_PRINT Serial

#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

char auth[] = "aec5825e0cee4708b9b293f0d8755fae";

char ssid[] = "xxxx";
char pass[] = "xxxx";

int sensorPin = 0;

BLYNK_READ(V5)
{
 int reading = analogRead(sensorPin); 
 float voltage = reading * 3.3; 
 voltage /= 1024.0;
 float temperatureC = (voltage - 0.5) * 100;
 Blynk.virtualWrite(V5, temperatureC); //sending to Blynk
}

void setup()
{
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
}

void loop()
{
  Blynk.run();
}

So something is happening. the code uploaded. i am getting values on the app however they not accurate. i remember with serial monitor they were making sense.