I am a newbie for IOT. Was trying to implement SMART Home Automation, stuck at last step where my relay needs to toggle based on GPIO pin state. Details Below:
Hard ware : Node Mcu + 5V Relay (Image Below)
Issue :
I have flashed standard ADAFRUIT MQTT LIBRARY. And was able to successfully toggle a LED Bulb based on the data feed sent from io.adafruit.com.
The problem started when I replaced the LED bulb with 5V Relay. As soon connected to VCC and GND of node MCU to vcc and gnd of the relay. Red light turned on fine. But connecting IN pin of Relay to D2 pin of mcu. Green light came up fine. But it never turned off an data feed change to OFF. Connecting IN pin of relay to many other pins of mcu kept the light on.
I am completely confused on this behavior any help is highly appreciated,
Flashed mqtt code below :
/***************************************************
Adafruit MQTT Library ESP8266 Example
Must use ESP8266 Arduino from:
https://github.com/esp8266/Arduino
Works great with Adafruit's Huzzah ESP board & Feather
----> https://www.adafruit.com/product/2471
----> https://www.adafruit.com/products/2821
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Tony DiCola for Adafruit Industries.
MIT license, all text above must be included in any redistribution
****************************************************/
#include <ESP8266WiFi.h>
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"
/************************* WiFi Access Point *********************************/
#define WLAN_SSID "Sunilwifi"
#define WLAN_PASS "14311431"
/************************* Adafruit.io Setup *********************************/
#define AIO_SERVER "io.adafruit.com"
#define AIO_SERVERPORT 1883 // use 8883 for SSL
#define AIO_USERNAME "sunildm4u"
#define AIO_KEY "xxxx dummy api code"
/************ Global State (you don't need to change this!) ******************/
// Create an ESP8266 WiFiClient class to connect to the MQTT server.
WiFiClient client;
// or... use WiFiFlientSecure for SSL
//WiFiClientSecure client;
// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
Adafruit_MQTT_Client mqtt(&client, AIO_SERVER, AIO_SERVERPORT, AIO_USERNAME, AIO_KEY);
/****************************** Feeds ***************************************/
// Setup a feed called 'photocell' for publishing.
// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
Adafruit_MQTT_Publish photocell = Adafruit_MQTT_Publish(&mqtt, AIO_USERNAME "/feeds/photocell");
// Setup a feed called 'onoff' for subscribing to changes.
Adafruit_MQTT_Subscribe onoffbutton = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/lightsdata");
/*************************** Sketch Code ************************************/
// Bug workaround for Arduino 1.6.6, it seems to need a function declaration
// for some reason (only affects ESP8266, likely an arduino-builder bug).
void MQTT_connect();
void setup() {
pinMode(D3, OUTPUT);
Serial.begin(115200);
delay(10);
Serial.println(F("Adafruit MQTT demo"));
// Connect to WiFi access point.
Serial.println(); Serial.println();
Serial.print("Connecting to ");
Serial.println(WLAN_SSID);
WiFi.begin(WLAN_SSID, WLAN_PASS);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println();
Serial.println("WiFi connected");
Serial.println("IP address: "); Serial.println(WiFi.localIP());
// Setup MQTT subscription for onoff feed.
mqtt.subscribe(&onoffbutton);
}
uint32_t x=0;
void loop() {
// Ensure the connection to the MQTT server is alive (this will make the first
// connection and automatically reconnect when disconnected). See the MQTT_connect
// function definition further below.
MQTT_connect();
// this is our 'wait for incoming subscription packets' busy subloop
// try to spend your time here
Adafruit_MQTT_Subscribe *subscription;
while ((subscription = mqtt.readSubscription(5000))) {
if (subscription == &onoffbutton) {
Serial.print(F("Got: "));
Serial.println((char *)onoffbutton.lastread);
if (strcmp((char *)onoffbutton.lastread, "ON") == 0) {
digitalWrite(D3, LOW);
}
if (strcmp((char *)onoffbutton.lastread, "OFF") == 0) {
digitalWrite(D3, HIGH);
}
}
}
// Now we can publish stuff!
Serial.print(F("\nSending photocell val "));
Serial.print(x);
Serial.print("...");
if (! photocell.publish(x++)) {
Serial.println(F("Failed"));
} else {
Serial.println(F("OK!"));
}
// ping the server to keep the mqtt connection alive
// NOT required if you are publishing once every KEEPALIVE seconds
/*
if(! mqtt.ping()) {
mqtt.disconnect();
}
*/
}
// Function to connect and reconnect as necessary to the MQTT server.
// Should be called in the loop function and it will take care if connecting.
void MQTT_connect() {
int8_t ret;
// Stop if already connected.
if (mqtt.connected()) {
return;
}
Serial.print("Connecting to MQTT... ");
uint8_t retries = 3;
while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
Serial.println(mqtt.connectErrorString(ret));
Serial.println("Retrying MQTT connection in 5 seconds...");
mqtt.disconnect();
delay(5000); // wait 5 seconds
retries--;
if (retries == 0) {
// basically die and wait for WDT to reset me
while (1);
}
}
Serial.println("MQTT Connected!");
}