Library error when I run the code on Arduino IDE - arduino

Question

I've got the folllowing errors:
In file included from C:\Users\Lenovo\OneDrive\Documents\Arduino\libraries\Blynk\src/Blynk/BlynkApi.h:37:0,
from C:\Users\Lenovo\OneDrive\Documents\Arduino\libraries\Blynk\src/BlynkApiArduino.h:14,
from C:\Users\Lenovo\OneDrive\Documents\Arduino\libraries\Blynk\src/BlynkSimpleEsp8266.h:24,
from C:\Users\Lenovo\OneDrive\Desktop\sketch_mar31a\sketch_mar31a.ino:36:
C:\Users\Lenovo\OneDrive\Documents\Arduino\libraries\Blynk\src/Blynk/BlynkTimer.h:36:21: error: redefinition of 'class BlynkTimer'
#define SimpleTimer BlynkTimer
^
C:\Users\Lenovo\OneDrive\Documents\Arduino\libraries\SimpleTimer-1.0.0/SimpleTimer.h:10:7: note: in expansion of macro 'SimpleTimer'
class SimpleTimer {
^
C:\Users\Lenovo\OneDrive\Documents\Arduino\libraries\Blynk\src/Blynk/BlynkTimer.h:36:21: error: previous definition of 'class BlynkTimer'
#define SimpleTimer BlynkTimer
^
C:\Users\Lenovo\OneDrive\Documents\Arduino\libraries\Blynk\src/Blynk/BlynkTimer.h:41:7: note: in expansion of macro 'SimpleTimer'
class SimpleTimer {
^
exit status 1
Eroare de compilare pentru placa NodeMCU 1.0 (ESP-12E Module).
When I used this code:
#define BLYNK_PRINT Serial // Comment this out to disable prints and save space
#include <SPI.h>
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h>
#include <DHT.h>
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "wwnCVJrGmlkVcYrYsCq-RjO2A0C5s16t"; //Enter the Auth code which was send by Blink
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "DIGI-7v32"; //Enter your WIFI Name
char pass[] = "2UWCQ6R4"; //Enter your WIFI Password
#define DHTPIN 2 // Digital pin 4
// Uncomment whatever type you're using!
#define DHTTYPE DHT11 // DHT 11
//#define DHTTYPE DHT22 // DHT 22, AM2302, AM2321
//#define DHTTYPE DHT21 // DHT 21, AM2301
DHT dht(DHTPIN, DHTTYPE);
SimpleTimer timer;
// This function sends Arduino's up time every second to Virtual Pin (5).
// In the app, Widget's reading frequency should be set to PUSH. This means
// that you define how often to send data to Blynk App.
void sendSensor()
{
float h = dht.readHumidity();
float t = dht.readTemperature(); // or dht.readTemperature(true) for Fahrenheit
if (isnan(h) || isnan(t)) {
Serial.println("Failed to read from DHT sensor!");
return;
}
// You can send any value at any time.
// Please don't send more that 10 values per second.
Blynk.virtualWrite(V5, h); //V5 is for Humidity
Blynk.virtualWrite(V6, t); //V6 is for Temperature
}
void setup()
{
Serial.begin(9600); // See the connection status in Serial Monitor
Blynk.begin(auth, ssid, pass);
dht.begin();
// Setup a function to be called every second
timer.setInterval(1000L, sendSensor);
}
void loop()
{
Blynk.run(); // Initiates Blynk
timer.run(); // Initiates SimpleTimer
}

Answer 1

Blynk uses an open source SimpleTimer library.
There are quite a few libraries called SimpleTimer out there - See GitHub Search Results.
If you have a different version of the library to that used by Blynk you'll probably get a compile error:
BlynkTimer.h: 36:21: error: redefinition of 'class BlynkTimer
If you use the library that Blynk uses - marcelloromani/Arduino-SimpleTimer - you will not get errors on build, and can #include <SimpleTimer.h> and use it alongside Blynk without problem.
If you are using Blynk it is advisable to use BynkTimer instead of `SimpleTimer' for the following reason:
When BlynkTimer struggles to run multiple times (due to a blocked loop), it just skips all the missed intervals, and calls your function only once. New Blynk Library Release v0.5.3 - June 2018
To make the change to your code, remove
#include <SimpleTimer.h>
and replace
SimpleTimer timer;
with
BlynkTimer timer;