A simple IOT demo with Explore ESP8266 Revision as of 18:15, 12 October 2015 by Guru (Talk | contribs) (diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Sandeep (talk) 16:49, 27 August 2015 (IST)

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We were invited today to give a seminar on "How to get started with Embedded Systems" in a local Engineering college. With very little time on hand, wanted to quickly show the capabilities of ESP8266. So I decided to make a temperature humidity logger. With Thingspeak.com, it was extremely easy to log data and even trigger tweets!

Components/Boards Used

1	Explore ESP8266 Wi-Fi Module
2	OLED Display Module 128X64
3	DHT11

Arduino code for ESP8266

	#include <DHT.h>
	#include <Wire.h>
	#include <ESP8266WiFi.h>
	#include "font.h"
	#define offset 0x00 // SDD1306 // offset=0 for SSD1306 controller
	//#define offset 0x02 // SH1106 // offset=2 for SH1106 controller
	#define OLED_address 0x3c
	String apiKey = "things_speak_api_key";
	char ssid[20] = "wifi ssid";
	char password[20] = "wifi password";
	char TempValue[15];
	String str;
	const char* server = "api.thingspeak.com";
	#define DHTPIN 5 // what pin we're connected to
	DHT dht(DHTPIN, DHT11,15);
	WiFiClient client;
	void setup() {
	Serial.begin(115200); // for debugging
	Wire.begin(0,2); // Initialize I2C and OLED Display
	init_OLED();
	reset_display();
	clear_display();
	delay(10);
	sendStrXY("Connecting to ",0,0);
	sendStrXY(ssid, 3, 0);
	// Setup the Internet
	WiFi.begin(ssid, password);
	int pos = 0;
	while (WiFi.status() != WL_CONNECTED) {
	delay(500);
	pos++;
	sendStrXY(".", 5, pos);
	}
	sendStrXY("connected", 5, 0);
	clear_display();
	delay(100);
	//Setup the display Screen
	sendStrXY("Explore Embedded" ,0,0);
	sendStrXY("Temp:",3,0);
	sendStrXY("Humidity:",4,0);
	sendStrXY("InternetOfThings",7,0);
	}
	//String TempValue;
	void loop() {
	float h = dht.readHumidity();
	float t = dht.readTemperature();
	char tvalue[5], hvalue[5];
	if (isnan(h) || isnan(t)) {
	Serial.println("Failed to read from DHT sensor!");
	return;
	}
	str = String(t);
	str.toCharArray(tvalue,15);
	sendStrXY(tvalue,3,10);
	str = String(h);
	str.toCharArray(hvalue,15);
	sendStrXY(hvalue,4,10);
	if (client.connect(server,80)) { // "184.106.153.149" or api.thingspeak.com
	String postStr = apiKey;
	postStr +="&field1=";
	postStr += String(t);
	postStr +="&field2=";
	postStr += String(h);
	postStr += "\r\n\r\n";
	client.print("POST /update HTTP/1.1\n");
	client.print("Host: api.thingspeak.com\n");
	client.print("Connection: close\n");
	client.print("X-THINGSPEAKAPIKEY: "+apiKey+"\n");
	client.print("Content-Type: application/x-www-form-urlencoded\n");
	client.print("Content-Length: ");
	client.print(postStr.length());
	client.print("\n\n");
	client.print(postStr);
	Serial.print("Temperature: ");
	Serial.print(t);
	Serial.print(" degrees Celcius Humidity: ");
	Serial.print(h);
	Serial.println("% send to Thingspeak");
	}
	client.stop();
	Serial.println("Waiting...");
	// thingspeak needs minimum 15 sec delay between updates
	delay(20000);
	}

view raw Explore-IOT-demo.ino hosted with ❤ by GitHub

Downloads

• Complete Arduino code

References and Credits

• https://hackaday.io/project/6132-esp8266oled this projected helped interfacing OLED with ESP8266
• Thanks to ESP8266 Arduino Community for porting Arduino
• DHT11 code library