Hello everyone I am currently working on a project which uses LM35 to get temperature values and if it falls below a certain value it will turn on a LED bulb using a relay however the relay does not work if someone can please help me I would appreciate
the code is :
#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include <DallasTemperature.h>
#include <OneWire.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266HTTPClient.h>
const char* ssid = "The Everly"; // Enter your WiFi name
const char* password = ""; // Enter WiFi password
const char* mqttServer = "192.168.16.12";
const int mqttPort = 1883;
const char* mqttUser = "iotadmin123";
const char* mqttPassword = "XR5nsgs0cSqy3vRfgdrKLm";
const int relay = D3;
WiFiClient espClient;
PubSubClient client(espClient);
#define ONE_WIRE_BUS D2 //D2 pin of nodemcu
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire); // Pass the oneWire reference to Dallas Temperature.
unsigned long currentMillis = 0;
unsigned long previous_display = 0;
unsigned long previous_mysql = 0;
unsigned long previous_reconnect = 0;
const int event_display = 3000;
const int event_mysql = 60010;
const int event_reconnect = 30020;
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
sensors.begin();
pinMode(relay, OUTPUT);
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to WiFi..");
}
Serial.println("Connected to the WiFi network");
client.setServer(mqttServer, mqttPort);
client.setCallback(callback);
while (!client.connected()) {
Serial.println("Connecting to MQTT...");
if (client.connect("bakery_freezer", mqttUser, mqttPassword )) {
Serial.println("connected");
} else {
Serial.print("failed with state ");
Serial.print(client.state());
delay(2000);
}
}
}
void callback(char* topic, byte* payload, unsigned int length) {
Serial.print("Message arrived in topic: ");
Serial.println(topic);
Serial.print("Message:");
for (int i = 0; i < length; i++) {
Serial.print((char)payload[i]);
}
Serial.println();
Serial.println("-----------------------");
}
void loop() {
currentMillis = millis();
if (!client.connected()) {
reconnect();
} else {
client.loop();
}
if (currentMillis - previous_display >= event_display){
sensors.requestTemperatures(); // Send the command to get temperatures
float temperature = (sensors.getTempCByIndex(0)); // Why "byIndex"? You can have more than one IC on the same bus. 0 refers to the first IC on the wire
char tempString[8];
dtostrf(temperature, 6, 2, tempString);
Serial.print("Temperature: ");
Serial.print(tempString);
Serial.println("°C");
client.publish("freezer4/bakery_freezer", tempString );
float temp = sensors.getTempCByIndex(0);
if (temp > -13){
digitalWrite(relay, LOW); // ON LED
client.publish("ledon/bakery_freezer", "Danger Temperature -13" );
}
else{
digitalWrite(relay, HIGH); // Off LED
client.publish("ledon/bakery_freezer", "Normal Temperature" );
}
previous_display = currentMillis ;
if (currentMillis - previous_mysql >= event_mysql ){
//WiFiClient client;
WiFiClient Client ;
HTTPClient http;
String tempr, postData;
tempr = tempString;
postData = "&tempr=" + tempr ;
http.begin(Client, "http://192.168.16.12/build/freezer_monitoring/bakery_freezer.php"); //Specify request destination
http.addHeader("Content-Type", "application/x-www-form-urlencoded"); //Specify content-type header
int httpCode = http.POST(postData); //Send the request
String payload = http.getString(); //Get the response payload
Serial.println(httpCode); //Print HTTP return code
Serial.println(payload); //Print request response payload
http.end(); //Close connection
previous_mysql = currentMillis ;
}
}
}
void reconnect() {
// Loop until we're reconnected
if (currentMillis - previous_reconnect >= event_reconnect) {
if (client.connect("bakery_freezer", mqttUser, mqttPassword)) {
Serial.println("Connected");
} else {
Serial.print("Connection failed, rc=");
Serial.print(client.state());
Serial.println("Reconnecting...");
}
previous_reconnect = currentMillis;
}
}
See