ESP8266 Community Forum

Hi
I am doing a science fair project for school, I am new to coding and don't fully understand it. I have already got a uv sensor working that publishes its data (uv index) onto an io.adafruit feed. I would like to get another esp8266 to subscribe to that feed and make an led turn on when the uv index gets to a high number and turn off when the uv index is at a lower number, this is my coding so far. I have already got the esp8266 to subscribe to my adafruit feed but it is turning off the led at any uv index strength.

[code][/code]

****************************************************/
#include <ESP8266WiFi.h>
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"

/************************* WiFi Access Point *********************************/

#define WLAN_SSID "..."
#define WLAN_PASS "..."

/************************* Adafruit.io Setup *********************************/

#define AIO_SERVER "io.adafruit.com"
#define AIO_SERVERPORT 1883 // 8883 for MQTTS
#define AIO_USERNAME "..."
#define AIO_KEY "..."

/************ 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 uv_index_feed = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/uv-index");

/*************************** Error Reporting *********************************/

Adafruit_MQTT_Subscribe errors = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/errors");
Adafruit_MQTT_Subscribe throttle = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/throttle");

/*************************** 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() {
// initialize digital pin 2 as an output.
pinMode(2, 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(&uv_index_feed);

// Setup MQTT subscriptions for throttle & error messages
mqtt.subscribe(&throttle);
mqtt.subscribe(&errors);

}


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 == &uv_index_feed) {
Serial.print(F("Got uv index: "));
Serial.println((char *)uv_index_feed.lastread);
} else if(subscription == &errors) {
Serial.print(F("ERROR: "));
Serial.println((char *)errors.lastread);
} else if(subscription == &throttle) {
Serial.println((char *)throttle.lastread);
} if (strcmp((char *)uv_index_feed.lastread, "<1") == 0) {
digitalWrite(2, LOW);
} if (strcmp((char *)uv_index_feed.lastread, ">1") == 0) {
digitalWrite(2, HIGH);
}
}
}

// 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!");
}

What I get when it scans the uv index.
Connecting to Wi-Fi
. . . .
Wi-Fi connected
IP adress:
Connecting to MQTT . . . MQTT Connected!
Got uv index 0.02