NodeMCU 8 Relay-PCF8574-I2C
Updated: Dec 4, 2021
In this project, we will control 8 relays via our smarthexiot software.You can continue this project after reviewing our previous relay control and pcf8574 examples.
#include <ESP8266WiFi.h> //The library we will use for the wifi connection
#include <PubSubClient.h> // The library we will use for the mqtt connection
//mqtt connection library settings
WiFiClient espClient;
PubSubClient client(espClient);
//
#include <Wire.h>
#include <PCF8574.h>
PCF8574 pcf20(0x20);
//
//settings for internet and mqtt connection
const char* ssid = ""; // wifi SSID
const char* password = ""; // wifi password
const char* mqttServer = ""; // mqtt server ip to be sent by smartespiot by mail
const int mqttPort = ; // mqtt port to be sent by smartespiot by mail
const char* mqttUser = ""; // mqtt username to be sent by smartespiot by mail
const char* mqttPassword = ""; // mqtt pass to be sent by smartespiot by mail
//
//****
String Topik; //Our variable that we will use for comparison by keeping the tags/topic information from mqtt
int relaystatus1 = 0; // relay status will be send smartespiot
int relaystatus2 = 0; // relay status will be send smartespiot
int relaystatus3 = 0; // relay status will be send smartespiot
int relaystatus4 = 0; // relay status will be send smartespiot
int relaystatus5 = 0; // relay status will be send smartespiot
int relaystatus6 = 0; // relay status will be send smartespiot
int relaystatus7 = 0; // relay status will be send smartespiot
int relaystatus8 = 0; // relay status will be send smartespiot
String relay1, relay2, relay3, relay4, relay5, relay6, relay7, relay8; // our variable to hold the message information
char message_store[100]; // variable to save the incoming message as a character
//***//
int wificounter = 0; // for counting the number of trying connections
//**//
void setup() {
Serial.begin(115200); // start serial communication at 115200 speed
Wire.begin(14, 12); // d6 scl d5 sda
pcf20.begin();
pcf20.write(0, 1);
pcf20.write(1, 1);
pcf20.write(2, 1);
pcf20.write(3, 1);
pcf20.write(4, 1);
pcf20.write(5, 1);
pcf20.write(6, 1);
pcf20.write(7, 1);
WiFi.begin(ssid, password); // start the wifi connection process
while (WiFi.status() != WL_CONNECTED) { //
delay(5000); //wait 5000ms
Serial.println("Connecting to wifi..."); // wait until the wifi process connects
//// trying 10 times connection after reset to esp
wificounter = wificounter + 1;
if (wificounter == 10) {
ESP.reset();
}
/////
}
Serial.println("Wifi connection ready :)"); // print the connection made information to the serial port
client.setServer(mqttServer, mqttPort);//start connecting to the mqtt server from the specified port
/////*****
client.setCallback(callback);
////******
while (!client.connected()) { //wait until we connect to mqtt
Serial.println("Connecting to MQTT server...");
if (client.connect("nodemcu1", mqttUser, mqttPassword )) {//login to mqtt server with username and password with smartespIOT name
Serial.println("MQTT connection established :) ");
} else {
Serial.print("Unable to connect... ");// If the connection cannot be established, let's give a warning
Serial.print(client.state()); // print the problem description
// We can understand the problem according to the information returned from the clients state.
//-4 : MQTT_CONNECTION_TIMEOUT - the server did not respond in the ongoing time
//-3 : MQTT_CONNECTION_LOST - network connection lost
//-2 : MQTT_CONNECT_FAILED - network connection failed
//-1 : MQTT_DISCONNECTED - disconnected
//0 : MQTT_CONNECTED - connection established
//1 : MQTT_CONNECT_BAD_PROTOCOL - The server does not support the requested MQTT version
//2 : MQTT_CONNECT_BAD_CLIENT_ID - The server did not accept your information
//3 : MQTT_CONNECT_UNAVAILABLE - The server did not accept the connectionetmed
//4 : MQTT_CONNECT_BAD_CREDENTIALS - username password not accepted
//5 : MQTT_CONNECT_UNAUTHORIZED - you are not authorized to connect
delay(2000); // wait two seconds and try connecting again
////
ESP.reset(); // unable to connect esp reset
///
}
}
////*****
client.subscribe("nodemcu1/relay1");
client.subscribe("nodemcu1/relay2");
client.subscribe("nodemcu1/relay3");
client.subscribe("nodemcu1/relay4");
client.subscribe("nodemcu1/relay5");
client.subscribe("nodemcu1/relay6");
client.subscribe("nodemcu1/relay7");
client.subscribe("nodemcu1/relay8");
////*****
}
////reconnect funtion //
void reconnect() {
WiFi.disconnect();
delay(100);
WiFi.begin(ssid, password); // start the wifi connection process
while (WiFi.status() != WL_CONNECTED) { //
delay(5000); //wait 5000ms
Serial.println("Connecting to wifi..."); // wait until the wifi process connects
//// trying 10 times connection after reset to esp
wificounter = wificounter + 1;
if (wificounter == 10) {
ESP.reset();
}
/////
}
Serial.println("Wifi connection ready :)"); // print the connection made information to the serial port
client.setServer(mqttServer, mqttPort);//start connecting to the mqtt server from the specified port
/////*****
client.setCallback(callback);
////******
while (!client.connected()) { //wait until we connect to mqtt
Serial.println("Connecting to MQTT server...");
if (client.connect("SmartEspIOT", mqttUser, mqttPassword )) {//login to mqtt server with username and password with smartespIOT name
Serial.println("MQTT connection established :) ");
} else {
Serial.print("Unable to connect... ");// If the connection cannot be established, let's give a warning
Serial.print(client.state()); // print the problem description
// We can understand the problem according to the information returned from the clients state.
//-4 : MQTT_CONNECTION_TIMEOUT - the server did not respond in the ongoing time
//-3 : MQTT_CONNECTION_LOST - network connection lost
//-2 : MQTT_CONNECT_FAILED - network connection failed
//-1 : MQTT_DISCONNECTED - disconnected
//0 : MQTT_CONNECTED - connection established
//1 : MQTT_CONNECT_BAD_PROTOCOL - The server does not support the requested MQTT version
//2 : MQTT_CONNECT_BAD_CLIENT_ID - The server did not accept your information
//3 : MQTT_CONNECT_UNAVAILABLE - The server did not accept the connectionetmed
//4 : MQTT_CONNECT_BAD_CREDENTIALS - username password not accepted
//5 : MQTT_CONNECT_UNAUTHORIZED - you are not authorized to connect
delay(2000); // wait two seconds and try connecting again
////
ESP.reset(); // unable to connect esp reset
///
}
}
////*****
client.subscribe("nodemcu1/relay1");
client.subscribe("nodemcu1/relay2");
client.subscribe("nodemcu1/relay3");
client.subscribe("nodemcu1/relay4");
client.subscribe("nodemcu1/relay5");
client.subscribe("nodemcu1/relay6");
client.subscribe("nodemcu1/relay7");
client.subscribe("nodemcu1/relay8");
////*****
}
////////////////////////////////////////
///****
void callback(char* topic, byte* payload, unsigned int length) { // Let's get the incoming topic-tag information and message
int i = 0;
Serial.println("message received");
Serial.println(topic); // Let's print the incoming topic-tag information to the serial port
Topik = String (topic); // write it to our variable to use the incoming topic information
Serial.print("incomming message:");
for (i = 0; i < length; i++) {
Serial.print((char)payload[i]); // write the incoming message to the serial port
message_store[i] = ((char)payload[i]); // store the incoming characters as characters in the message store
}
message_store[i] = '\0'; // find the end of the message
// Now let's find our data from the incoming message
if (Topik == "nodemcu1/relay1") {
relay1 = (message_store);
}
if (Topik == "nodemcu1/relay2") {
relay2 = (message_store);
}
if (Topik == "nodemcu1/relay3") {
relay3 = (message_store);
}
if (Topik == "nodemcu1/relay4") {
relay3 = (message_store);
}
if (Topik == "nodemcu1/relay5") {
relay5 = (message_store);
}
if (Topik == "nodemcu1/relay6") {
relay6 = (message_store);
}
if (Topik == "nodemcu1/relay7") {
relay7 = (message_store);
}
if (Topik == "nodemcu1/relay8") {
relay8 = (message_store);
}
}
/////*******
void loop() {
client.loop(); // mrun the mqtt data processing function
///// test client connected and start reconnect ///
if (!client.connected()) {
reconnect();
}
////relay 1
if ((relay1 == "1") && (relaystatus1 == 0)) { //
relaystatus1 = 1;
pcf20.write(0, LOW);
client.publish("nodemcu1/relaystatus1", String(relaystatus1).c_str());// send relay status
}
if ((relay1 == "0") && (relaystatus1 == 1)) {
relaystatus1 = 0;
pcf20.write(0, HIGH);
client.publish("nodemcu1/relaystatus1", String(relaystatus1).c_str());// send relay status
}
/////
////relay 2
if ((relay2 == "1") && (relaystatus2 == 0)) { //
relaystatus2 = 1;
pcf20.write(1, LOW);
client.publish("nodemcu1/relaystatus2", String(relaystatus2).c_str());// send relay status
}
if ((relay2 == "0") && (relaystatus2 == 1)) {
relaystatus2 = 0;
pcf20.write(1, HIGH);
client.publish("nodemcu1/relaystatus2", String(relaystatus2).c_str());// send relay status
}
/////
////relay 3
if ((relay3 == "1") && (relaystatus3 == 0)) { //
relaystatus3 = 1;
pcf20.write(2, LOW);
client.publish("nodemcu1/relaystatus3", String(relaystatus3).c_str());// send relay status
}
if ((relay3 == "0") && (relaystatus3 == 1)) {
relaystatus3 = 0;
pcf20.write(2, HIGH);
client.publish("nodemcu1/relaystatus3", String(relaystatus3).c_str());// send relay status
}
/////
////relay 4
if ((relay4 == "1") && (relaystatus4 == 0)) { //
relaystatus4 = 1;
pcf20.write(3, LOW);
client.publish("nodemcu1/relaystatus4", String(relaystatus4).c_str());// send relay status
}
if ((relay4 == "0") && (relaystatus4 == 1)) {
relaystatus4 = 0;
pcf20.write(3, HIGH);
client.publish("nodemcu1/relaystatus4", String(relaystatus4).c_str());// send relay status
}
/////
////relay 5
if ((relay5 == "1") && (relaystatus5 == 0)) { //
relaystatus5 = 1;
pcf20.write(4, LOW);
client.publish("nodemcu1/relaystatus5", String(relaystatus5).c_str());// send relay status
}
if ((relay5 == "0") && (relaystatus5 == 1)) {
relaystatus5 = 0;
pcf20.write(4, HIGH);
client.publish("nodemcu1/relaystatus5", String(relaystatus5).c_str());// send relay status
}
/////
////relay 6
if ((relay6 == "1") && (relaystatus6 == 0)) { //
relaystatus6 = 1;
pcf20.write(5, LOW);
client.publish("nodemcu1/relaystatus6", String(relaystatus6