Today, I will show how to combine three commonly used IoT libraries;
WiFimanager, AsyncElegantOTA, and MQTT To become a common IoT code base. So, for our future projects, ESP8266 or ESP32, would have these basic functions.
Let's first look at these three libraries:
Wifimanager = Wi-Fi password management, no need to re-burn the code to change the Wi-Fi SSID & password
FOTA = Use Wi-Fi to update ESP32 code, you can burn code without connecting to USB
MQTT = Streamlined and lightweight communication protocol (Message Queueing Telemetry Transport)
This episode will only introduce how to integrate MQTT into Wifimanager + AsyncElegantFOTA.
To learn how to start Wifimanager + AsyncElegantOTA, Please watch Android #27 Wifimanager + OTA for ESP32/ESP8266 (ESPAsyncWifimanager / ESPAsyncElegantOTA)) https://youtu.be/UlRLTvl4DRc
If you don't have enough time, you can also select the part you want to watch from the timeline below!
Video Timeline:
00:00 Start
01:39 Demonstration of project results
01:57 mqttgo.io MQTT server, free, fast, & stable
05:52 Install three libraries
07:14 Added two ESP32 PINs as MQTT example
07:41 Encrypt the firmware update (ElegantOTA) page
11:44 Explain how the MQTT callback function works
13:07 Control ESP32 I/O pins with MQTT
15:16 Future program can be written from here
/**
* Arduino code base for IoT Projects
* By: Stonez56 aka Kevin Chen 2022-08-16
*
* This source code combined three most common Arduino libraries for IoT Projects,
* ESPAsync_Wifimanager, AsyncElegantOTA, & Pubsubclient MQTT Client.
*
* 1. ESPAsync_WiFiManager: https://github.com/khoih-prog/ESPAsync_WiFiManager
* 2. AsyncElegantOTA: https://github.com/ayushsharma82/AsyncElegantOTA
* 3. Pubsubclient MQTT Client: https://github.com/knolleary/pubsubclient
*
* YouTube video: https://youtu.be/giFHp9RSMvQ
* Source code is available my blog: https://stonez56.blogspot.com/2022/08/android-36-iot-wifimanager-fota-mqtt.html
**/
/*
* Define Relay pins as examples to send/receive MQTT messages
* **/
#define RELAY_PIN_1 12
#define RELAY_PIN_2 14
/**
* Perform OTAs for ESP8266 / ESP32 Elegantly with password protection!
* https://github.com/ayushsharma82/AsyncElegantOTA
* **/
#include <AsyncElegantOTA.h>
const char *FOTA_USERNAME = "un";
const char *FOTA_PASSWORD = "pw";
/**
* Add MQTT client here` PubSubClient V2.8 by Nick O'Leary
* https://github.com/knolleary/pubsubclient
*/
#include <WiFiClient.h>
#include <PubSubClient.h>
#define MSG_BUFFER_SIZE (1024)
char msg[MSG_BUFFER_SIZE];
/** Taiwan No. 1 Free MQTT Server!! **/
const char *mqtt_server = "mqttgo.io";
const int mqtt_port = 1883;
/****************************************************************************************************************************
Async_AutoConnect_ESP32_minimal.ino
For ESP8266 / ESP32 boards
Built by Khoi Hoang https://github.com/khoih-prog/ESPAsync_WiFiManager
Licensed under MIT license
*****************************************************************************************************************************/
#if !(defined(ESP32))
#error This code is intended to run on the ESP32 platform! Please check your Tools->Board setting.
#endif
#include <ESPAsync_WiFiManager.h>
AsyncWebServer webServer(80);
//Start DNS server
DNSServer dnsServer;
//MQTT - Start WiFi client and connect to MQTT server
WiFiClient espClient;
PubSubClient mqtt_client(espClient);
//Define device name
String DEVICE_NAME = "Dual_Relay_Switch";
String home_page_message = "";
void setup()
{
Serial.begin(115200);
pinMode(RELAY_PIN_1, OUTPUT);
pinMode(RELAY_PIN_2, OUTPUT);
while (!Serial)
;
delay(200);
Serial.print("\nAsyncWifimanager started on " + String(ARDUINO_BOARD) + "\n");
//Initialize ESPAsyncWifimanager instance and assign Wi-Fi Client name "AsyncAutoConnect"!
//This name and IP address can be checked from the router
ESPAsync_WiFiManager ESPAsync_wifiManager(&webServer, &dnsServer, "Dual_Relay_Switch");
//####### RESET SAVED WIFI SETTINGS #############
//ESPAsync_wifiManager.resetSettings();
//ESPAsync_wifiManager.setAPStaticIPConfig(IPAddress(192, 168, 132, 1), IPAddress(192, 168, 132, 1), IPAddress(255, 255, 255, 0));
//ESPAsync_wifiManager.autoConnect("Stonez_ESP32S", "AP-NAME", "AP-PASSWORD");
ESPAsync_wifiManager.autoConnect("Dual_Switch_ESP32S");
if (WiFi.status() == WL_CONNECTED)
{
Serial.print(DEVICE_NAME);
Serial.print(" is on Local IP: ");
Serial.println(WiFi.localIP());
}
else
{
Serial.println(ESPAsync_wifiManager.getStatus(WiFi.status()));
}
//Setup home page access content when visite
home_page_message = "<!DOCTYPE html><html><head><title>" + DEVICE_NAME
+ "</title></head><body><p><h2> Hi! This is " + DEVICE_NAME + "</h2>"
+ "To update firmware, <a href='/update'>Click here!!</a><br/><span>Username & Password required!</span></p><body></html>";
webServer.on("/", HTTP_GET, [](AsyncWebServerRequest *request)
{ request->send(200, "text/html", home_page_message); });
//AsyncElegantOTA.begin(&webServer); // Start ElegantOTA WITHOUT username & password
AsyncElegantOTA.begin(&webServer, FOTA_USERNAME, FOTA_PASSWORD); // Start ElegantOTA with username & password
webServer.begin();
Serial.println("AsyncElegantOTA server started @URL/update");
//MQTT starts here!
mqtt_client.setServer(mqtt_server, mqtt_port);
mqtt_client.setCallback(callback);
}
/**
//When MQTT lost connection, this function will be called to reconnect MQTT//
* Modified to accept multiple MQTT topics
* https://www.baldengineer.com/multiple-mqtt-topics-pubsubclient.html
*/
void callback(char *topic, byte *payload, unsigned int length)
{
//Print message received
Serial.print("Message arrived [");
Serial.print(topic);
Serial.print("] ");
for (int i = 0; i < length; i++)
{
Serial.print((char)payload[i]);
}
Serial.println();
//Process multiple topics here//
payload[length] = '\0';
String message = (char*)payload;
if (strcmp(topic, "studio/humd_switch") == 0)
{
if(message == "true"){
digitalWrite(RELAY_PIN_1, HIGH);
Serial.println("humd_switch true");
}
if(message == "false"){
digitalWrite(RELAY_PIN_1, LOW);
Serial.println("humd_switch false");
}
}
if (strcmp(topic, "studio/humd_switch2") == 0)
{
if(message == "true"){
digitalWrite(RELAY_PIN_2, HIGH);
Serial.println("humd_switch2 true");
}
if(message == "false"){
digitalWrite(RELAY_PIN_2, LOW);
Serial.println("humd_switch2 false");
}
}
}
//============= MQTT ===================
//When MQTT lost connection, this function will be called to reconnect MQTT//
void reconnect(){
//Loop while MQTT connected
while (!mqtt_client.connected())
{
Serial.print("Attempting MQTT connection... ");
// Create a random client ID
String clientId = "Stonez_ESP32Client-";
clientId += String(random(0xffff), HEX);
// Attempt to connect
if (mqtt_client.connect(clientId.c_str()))
{
Serial.print("connected to ");
Serial.print(mqtt_server);
// Once connected, publish an announcement...
mqtt_client.publish("outTopic", "Hello world");
// ... and resubscribe
mqtt_client.subscribe("studio/humd_switch");
mqtt_client.subscribe("studio/humd_switch2");
}
else
{
Serial.print("failed, rc=");
Serial.print(mqtt_client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
void loop() {
//============= MQTT ===================
//if can't connect to MQTT server, then re-connect
if (!mqtt_client.connected())
{ reconnect(); }
//constantly check MQTT to see for messages sending/receiving
mqtt_client.loop();
/**
* Write your own code here....
*
*/
}
Async_AutoConnect_ESP32_minimal.ino
/****************************************************************************************************************************
Async_AutoConnect_ESP32_minimal.ino
For ESP8266 / ESP32 boards
Built by Khoi Hoang https://github.com/khoih-prog/ESPAsync_WiFiManager
Licensed under MIT license
*****************************************************************************************************************************/
#if !(defined(ESP32) )
#error This code is intended to run on the ESP32 platform! Please check your Tools->Board setting.
#endif
#include <ESPAsync_WiFiManager.h> //https://github.com/khoih-prog/ESPAsync_WiFiManager
AsyncWebServer webServer(80);
DNSServer dnsServer;
void setup()
{
// put your setup code here, to run once:
Serial.begin(115200); while (!Serial); delay(200);
Serial.print("\nStarting Async_AutoConnect_ESP32_minimal on " + String(ARDUINO_BOARD)); Serial.println(ESP_ASYNC_WIFIMANAGER_VERSION);
ESPAsync_WiFiManager ESPAsync_wifiManager(&webServer, &dnsServer, "AutoConnectAP");
//ESPAsync_wifiManager.resetSettings(); //reset saved settings
ESPAsync_wifiManager.setAPStaticIPConfig(IPAddress(192,168,132,1), IPAddress(192,168,132,1), IPAddress(255,255,255,0));
ESPAsync_wifiManager.autoConnect("AutoConnectAP");
if (WiFi.status() == WL_CONNECTED) { Serial.print(F("Connected. Local IP: ")); Serial.println(WiFi.localIP()); }
else { Serial.println(ESPAsync_wifiManager.getStatus(WiFi.status())); }
}
void loop() { }
Async_AutoConnect_ESP8266_minimal.ino
/****************************************************************************************************************************
Async_AutoConnect_ESP8266_minimal.ino
For ESP8266 / ESP32 boards
Built by Khoi Hoang https://github.com/khoih-prog/ESPAsync_WiFiManager
Licensed under MIT license
*****************************************************************************************************************************/
#if !( defined(ESP8266) )
#error This code is intended to run on ESP8266 platform! Please check your Tools->Board setting.
#endif
#include <ESPAsync_WiFiManager.h> //https://github.com/khoih-prog/ESPAsync_WiFiManager
AsyncWebServer webServer(80);
DNSServer dnsServer;
void setup()
{
// put your setup code here, to run once:
Serial.begin(115200); while (!Serial); delay(200);
Serial.print("\nStarting Async_AutoConnect_ESP8266_minimal on " + String(ARDUINO_BOARD)); Serial.println(ESP_ASYNC_WIFIMANAGER_VERSION);
ESPAsync_WiFiManager ESPAsync_wifiManager(&webServer, &dnsServer, "AutoConnectAP");
//ESPAsync_wifiManager.resetSettings(); //reset saved settings
//ESPAsync_wifiManager.setAPStaticIPConfig(IPAddress(192,168,186,1), IPAddress(192,168,186,1), IPAddress(255,255,255,0));
ESPAsync_wifiManager.autoConnect("AutoConnectAP");
if (WiFi.status() == WL_CONNECTED) { Serial.print(F("Connected. Local IP: ")); Serial.println(WiFi.localIP()); }
else { Serial.println(ESPAsync_wifiManager.getStatus(WiFi.status())); }
}
void loop() { }
/*
Basic ESP8266 MQTT example
This sketch demonstrates the capabilities of the pubsub library in combination
with the ESP8266 board/library.
It connects to an MQTT server then:
- publishes "hello world" to the topic "outTopic" every two seconds
- subscribes to the topic "inTopic", printing out any messages
it receives. NB - it assumes the received payloads are strings not binary
- If the first character of the topic "inTopic" is an 1, switch ON the ESP Led,
else switch it off
It will reconnect to the server if the connection is lost using a blocking
reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
achieve the same result without blocking the main loop.
To install the ESP8266 board, (using Arduino 1.6.4+):
- Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
http://arduino.esp8266.com/stable/package_esp8266com_index.json
- Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
- Select your ESP8266 in "Tools -> Board"
*/
#include <WiFi.h>
#include <PubSubClient.h>
#include <EasyButton.h>
#define LED 2 //built-in LED on ESP32
#include "DHT.h"
#define DHTPIN 23 // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11 // DHT11
DHT dht(DHTPIN, DHTTYPE); // Initialize DHT sensor.
// Set up the temp / humidity update cycle
const int updateCycle = 5000;
// Update these with values suitable for your network.
const char *ssid = "Wi-Fi SSID";
const char *password = "Wi-Fi Password";
// Define your client ID on EMQX
String mqtt_ClientID = "stonez56_IOT_Station_";
// Define your topics to subscribe / publish
const char* sub_topic = "stonez56/esp32s";
const char* pub_led_topic = "stonez56/esp32s_led_state";
const char* pub_init_topic = "stonez56/esp32s_is_back";
const char* pub_temp_topic = "stonez56/esp32s_temp";
const char* pub_humd_topic = "stonez56/esp32s_humd";
// EMQX broker parameters
const char *mqtt_server = "broker.emqx.io";
const char *mqtt_userName = "emqx";
const char *mqtt_password = "public";
WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (50)
char msg[MSG_BUFFER_SIZE];
char msg1[MSG_BUFFER_SIZE];
int value = 0;
void setup_wifi()
{
delay(10);
// We start by connecting to a WiFi network
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
randomSeed(micros());
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
void callback(char *topic, byte *payload, unsigned int length)
{
Serial.print("Message arrived [");
Serial.print(topic);
Serial.print("] ");
for (int i = 0; i < length; i++)
{
Serial.print((char)payload[i]);
}
Serial.println();
payload[length] = '\0';
String message = (char *)payload;
if (strcmp(topic, sub_topic) == 0)
{
if (message == "off")
{
digitalWrite(LED, LOW); //Turn off
client.publish(pub_led_topic, "off");
}
if (message == "on")
{
digitalWrite(LED, HIGH); //Turn on
client.publish(pub_led_topic, "on");
}
}
/* Switch on the LED if an 1 was received as first character
// if ((char)payload[0] == '1')
// {
// digitalWrite(BUILTIN_LED, LOW); // Turn the LED on (Note that LOW is the voltage level
// // but actually the LED is on; this is because
// // it is active low on the ESP-01)
// }
// else
// {
// digitalWrite(BUILTIN_LED, HIGH); // Turn the LED off by making the voltage HIGH
// } */
}
void reconnect()
{
// Loop until we're reconnected
while (!client.connected())
{
Serial.println("Attempting EMQX MQTT connection...");
// Create a random client ID
mqtt_ClientID += String(random(0xffff), HEX);
// Attempt to connect
if (client.connect((mqtt_ClientID, mqtt_userName, mqtt_password)))
{
Serial.print(" connected with Client ID: ");
Serial.println(mqtt_ClientID);
// Once connected, publish an announcement...
client.publish(pub_init_topic, "Hi, I'm online!");
// ... and resubscribe
client.subscribe(sub_topic);
}
else
{
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
void setup()
{
//Start DH11 sensor
dht.begin();
pinMode(LED, OUTPUT); // Initialize the _LED pin as an output
digitalWrite(LED, LOW); //default ESP32 LOW is turn off
Serial.begin(115200);
setup_wifi();
client.setServer(mqtt_server, 1883);
client.setCallback(callback);
}
void loop()
{
if (!client.connected())
{
reconnect();
}
client.loop();
unsigned long now = millis();
if (now - lastMsg > updateCycle)
{
lastMsg = now;
float humidity = dht.readHumidity();
float temperature = dht.readTemperature();
// Check if any reads failed and exit early (to try again).
if (isnan(humidity) || isnan(temperature))
{
Serial.println(F("Failed to read from DHT sensor!"));
return;
}else{ // publish the message
snprintf(msg, MSG_BUFFER_SIZE, "%.1lf°", temperature);
snprintf(msg1, MSG_BUFFER_SIZE,"%.0lf%%", humidity);
Serial.print("Publish message: ");
Serial.println(msg);
client.publish(pub_temp_topic, msg);
client.publish(pub_humd_topic, msg1);
}
}
}
/*
Basic ESP8266 MQTT example
This sketch demonstrates the capabilities of the pubsub library in combination
with the ESP8266 board/library.
It connects to an MQTT server then:
- publishes "hello world" to the topic "outTopic" every two seconds
- subscribes to the topic "inTopic", printing out any messages
it receives. NB - it assumes the received payloads are strings not binary
- If the first character of the topic "inTopic" is an 1, switch ON the ESP Led,
else switch it off
It will reconnect to the server if the connection is lost using a blocking
reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
achieve the same result without blocking the main loop.
To install the ESP8266 board, (using Arduino 1.6.4+):
- Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
http://arduino.esp8266.com/stable/package_esp8266com_index.json
- Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
- Select your ESP8266 in "Tools -> Board"
*/
#include <WiFi.h>
#include <PubSubClient.h>
#include <EasyButton.h>
#define LED 2 //built-in LED on ESP32
// Update these with values suitable for your network.
const char *ssid = "WiFi-SSID";
const char *password = "WiFi-PASSWORD";
// Define your client ID on EMQX
String mqtt_ClientID = "stonez56_IOT_Station_";
// Define your topics to subscribe / publish
const char* sub_topic = "stonez56/esp32s";
const char* pub_led_topic = "stonez56/esp32s_led_state";
const char* pub_init_topic = "stonez56/esp32s_is_back";
// EMQX broker parameters
const char *mqtt_server = "broker.emqx.io";
const char *mqtt_userName = "emqx";
const char *mqtt_password = "public";
WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (50)
char msg[MSG_BUFFER_SIZE];
int value = 0;
void setup_wifi()
{
delay(10);
// We start by connecting to a WiFi network
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
randomSeed(micros());
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
void callback(char *topic, byte *payload, unsigned int length)
{
Serial.print("Message arrived [");
Serial.print(topic);
Serial.print("] ");
for (int i = 0; i < length; i++)
{
Serial.print((char)payload[i]);
}
Serial.println();
payload[length] = '\0';
String message = (char *)payload;
if (strcmp(topic, sub_topic) == 0)
{
if (message == "off")
{
digitalWrite(LED, LOW); //Turn off
client.publish(pub_led_topic, "off");
}
if (message == "on")
{
digitalWrite(LED, HIGH); //Turn on
client.publish(pub_led_topic, "on");
}
}
/* Switch on the LED if an 1 was received as first character
// if ((char)payload[0] == '1')
// {
// digitalWrite(BUILTIN_LED, LOW); // Turn the LED on (Note that LOW is the voltage level
// // but actually the LED is on; this is because
// // it is active low on the ESP-01)
// }
// else
// {
// digitalWrite(BUILTIN_LED, HIGH); // Turn the LED off by making the voltage HIGH
// } */
}
void reconnect()
{
// Loop until we're reconnected
while (!client.connected())
{
Serial.println("Attempting EMQX MQTT connection...");
// Create a random client ID
mqtt_ClientID += String(random(0xffff), HEX);
// Attempt to connect
if (client.connect((mqtt_ClientID, mqtt_userName, mqtt_password)))
{
Serial.print(" connected with Client ID: ");
Serial.println(mqtt_ClientID);
// Once connected, publish an announcement...
client.publish(pub_init_topic, "Hi, I'm online!");
// ... and resubscribe
client.subscribe(sub_topic);
}
else
{
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
void setup()
{
pinMode(LED, OUTPUT); // Initialize the _LED pin as an output
digitalWrite(LED, LOW); //default ESP32 LOW is turn off
Serial.begin(115200);
setup_wifi();
client.setServer(mqtt_server, 1883);
client.setCallback(callback);
}
void loop()
{
if (!client.connected())
{
reconnect();
}
client.loop();
/* unsigned long now = millis();
// if (now - lastMsg > 2000)
// {
// lastMsg = now;
// ++value;
// snprintf(msg, MSG_BUFFER_SIZE, "hello world #%ld", value);
// Serial.print("Publish message: ");
// Serial.println(msg);
// client.publish("stonez56/esp32s_button_pushed", msg);
// } */
}
Have you met this problem before? You were making an fantastic Arduino IoT project. However, in the code, Wi-Fi SSID and Password were hard-coded and the only way to change these is to edit the code and re-upload the code to Arduino. At home, this is okay, since you were experimenting things here and there anyway.
Let’s say you bring this project to a friend place or a venue to demo. And you didn’t know the Wi-Fi SSID nor the password beforehand. Then, you need to bring your computer to change SSID and password and re-upload to Arduino.
Is there a way to get rid this problem? Yes. The answer is use Arduino Wifimanager library.
Start
Open Arduino IDE. From Tools and select Manager Library in space here type Wi-Fi Manager to search
Arduino IDE will filter keywords with Wi-Fi manager. Scroll down until you find a Wi-Fi manager by author Zabu. The current version 0.14 just click and install. Ok, install completed. Click close.
Upload "Auto Connect" sketch to NodeMCU
Next, let's get a Wi-Fi Manager code. example from Files-> Example, scroll down and find Wi-Fi manager. Let's open "Auto Connect" in a new window.
In the "Auto Connect" code., let's not make any change and upload this code directly to NODEMCU to understand how it worked.
Now, let me compile the code and upload this code to my NODEMCU Compiled sketch.
This will take a while depending on your computer configuration. You can see the progress bar is showing here it's uploading the flashing LED indicates the program is uploading. Let's wait until upload complete. Okay.
Set it up on your smartphone
Upload completed. Let's look at the Arduino Serial port right now. It says: using last saved values, should be faster. Since this is a new NODEMCU and I haven't set anything to it in the program code. There's neither Wi-Fi SSID nor password setting. The "AutoConnectAP" is AP name that you could define yourself.
Let's see the serial monitor NODEMCU now acts as Wi-Fi AP named AutoConnectAP and waiting for Wi-Fi client connection. As I said this NODEMCU is now in Wi-Fi AP mode with IP address 192.168.4.1 What I need to do now is to input this IP address in a browser either smartphone or a computer. Let me enter this IP address into my smartphone browser.
Type IP here 192.168.4.1 Remember to connect the phone to NODEMCU Wi-Fi AutoConnectAP first.
Swipe down and click Wi-Fi symbol and then click AutoConnectAP from available Wi-Fi list. It's connected to AutoConnectAP.
The Wi-Fi manager AP page will show up on your smartphone now.
On this page let's, click configure Wi-Fi. Wi-Fi Manager will scan adjacent available Wi-Fi AP and show them here. Let me click my home Wi-Fi AP named stonez24 and and type in Wi-Fi password. Password entered and click Save.
it shows Credential saved. Let's look here NODEMCU you will now connect tostonez24 AP automatically.
Ready to go!
Okay, connection result shows connected. Great!! We have connected NODEMCU to Stonez24 AP. In the future when you visit a new place or venue, there's no need to Hard-Code SSID or password in Arduino code let Wifimanager do the hard work for you!
That's all for today's tutorial. I hope you find this useful!
I wanted to test out ESP8266 for a long time. However, I never got it to work until today. There are many tutorials and articles detailed how to make ESP8266 work, but even I followed many of those tutorials step by step mine ESP8266 just didn't work. It was very frustrating not able to figure out what went wrong. Anyway, I got it worked today, so it's better for me to write the steps down, not just for blog visitor like you, but also for myself as a good reference later on.
Previous three failed attempts... 😒
Different Version of ESP8266
There are many ESP8266 variations, the one I used for this tutorial is ESP8266-12E. Please refer to this page[2]to get more information for ESP8266 variations.
ESP8266 Pin Assignment
Most of the people probably will solder ESP8266 with metal covers facing up, so I placed a reversed pin assignment on the right side for easier pin reference.
Material Needed:
ESP8266-12E * 1
Perfboard * 1
Breadboard * 1
Wires - as many as needed
Resistors 1K * 4
CP2102 USB-Serial Converter * 1
Tools Needed:
Power supply (3.3V)
Soldering iron
Solder Tin
Plier-wire cutter
Plier
Step One:
ESP8266 has 2mm pin pitch instead of 2.54mm standard pitch. So we have to place it on a prefboard to make connections easier.
Place ESP8266 on a prefboard and draw its relative size that's larger to accommodate pins along both sides for easier connections with DuPoint wires. Cut down the piece of prefboard with a plier.
[Important: I later found out from the ESP8266 datasheet recommended to place Wi-Fi antenna outside of prefboard to get better signal reception & transmission.] 😄
Step Two:
Solder wires on each ESP8266 pin to the prefboard as shown below. I found out that after stripped skin of the wires, soldering job just got a little bit easier.
Note: My previous attempt was to solder wires without strip the wire skin and it was more difficult to solder; harder to bend the wires. Be careful, do not short these wires! :)
Step Three:
Solder 8 pin headers on each side of ESP8266 as shown below.
Step Four:
Time to connect all wires together. Check out the schematic diagram below for all the connections needed.
Schematic Diagram
ESP8266 Connection:
VCC -> 3.3V power source
EN-CHPD -> 1K resistor -> 3.3V
Reset -> 1K resistor -> 3.3V
TX -> USB/UART RX
RX -> USB/UART TX
GPIO0 -> do not connect anything for this AT command tutorial
GPIO15 -> 1K resistor -> GND
GND -> GND
CP2012 USB/UART Connection
RX -> ESP8266 TX
TX -> ESP8266 RX
GND -> GND (command ground with ESP8266)
NOTE:
Supply 3.3V to EPS8266! 5V will burn ESP8266!
GPIO-0 is connected to GND: upload Arduino programming code.
GPIO-0 is not connected: Enter AT Command.
Step Five:
Here, I used a red breadboard for wire connections with resistors and the power supply. As long as you follow the schematic diagram above and wiring tips for the connection, it shouldn't be too difficult. (I only use two transistors to share with common pins to VCC and GND. Not sure if this is a good practice?)
I have purchased an inexpensive power supply as the 3.3V power source. It displayed the how much the current is using, in this case "068mA", allowing me to see what power was consumed at the particular point of time, which it's very convenient! I checked ESP8266 datasheet "68mA ~ 71mA" means it's working probably.
Step Six:
Test AT Command. I think this is a quick method to check whether the ESP8266 is working or not.
Connect CP2012 to a Mac USB port
Power on power supply with 3.3V
Arduino IDE Operations:
First, let's load ESP8266 Library into Arduino IDE
Copy this string "http://arduino.esp8266.com/stable/package_esp8266com_index.json" into Arduino IDE preference -> Settings -> Additional Board Manager URLs. See below in yellow highlighted strings.
Select correct Arduino board type. Select "ESPino (ESP-12 module)" If you don't see this option, please restart Arduino IDE to ensure the library is properly loaded.
Select Port from port list. My serial port is /dev/cu.SLAB_USBtoUART
Click [Tools] - [Serial Monitor] from Arduino IDE to open the serial monitor.
Select baud rate from the baud rate list below. Select [115200 baud]. Your ESP8266 might have default baud rate of 9600 or 38400. If 15200 doesn't work, please try all other baud rate values.
Start AT Command
AT: You should be able to see the terminal replied "AT OK" back. Congratulation, your ESP8266 is working!
AT+GMR: Display ESP8266 firmware version. My ESP8266 is V1.2.0.0 Date: Dec 2, 2016.
AT+CWJAP="Wi-Fi_SSID","Password": Connect to the particular Wi-Fi Access point with the password designated. As you can see, the WiFi got connected immediately.
AT+CWMODE?[1]: Setup ESP8266 working mode. Let's setup ESP8266 to mode 3 both STA and AP. This allows ESP8266 connecting to your Wi-Fi router/Access point as a client also works as a router/Access point allowing other Wi-Fi client connect to it.
AT+CWMODE=1: STA (Become a Wi-Fi client to connect to AP)
AT+CWMODE=2: AP (Become an Assess point, so other clients can connect to this AP)
AT+CWMODE=3: BOTH = STA + AP (As an access point and a Wi-Fi client)
AT+CIFSR: Get IP Address. Since we setup CWMODE=3 (STA+AP mode), the first IP you see is AP IP (ESP8266 IP 192.168.4.1), the second IP is the WAN IP(your Wi-Fi IP 192.168.0.105 where ESP8266 is connected to)
AT+CWLAP: Scan Wi-Fi AP in the nearby area and show them all in a list. Text in first double quotes are WI-Fi SSID.
AT+RST: Reset command to reset ESP8266
It's great! Your ESP8266 is ready to connect to the Internet.
Load First Arduino Code:
ESP8266 can be used as an Arduino board itself without buying another Arduino board to work with ESP8266. Let's flash Arduino code into ESP8266 to test it out.
Connect GPIO0 -> 1K resistor -> GND (Without GPIO0 pull low, you can't flash code to ESP8266!
Copy the code below into your Arduino IDE and upload the code and the ESP8266-12E
********************************************************************************* IMPORTANT: After you upload Arduino codes, the AT command will no longer work. If you still prefer use AT command with ESP8266, you have to reflash AT command firmware to enable it. It took me few days to figure out this! *********************************************************************************
First Arduino code for ESP8266-12E, Connect to Wifi
This Arduino code below will connect ESP8266 to your WiFi AP/router and display the IP address it obtain. For this code to work, please replace Wifi_SSID with your Wifi-SSID and Wifi_Password with your own Wifi-Password. Do not forget to open Arduino IDE serial port to see the connection message!
#include <ESP8266WiFi.h>
void setup()
{
Serial.begin(115200);
Serial.println();
pinMode(LED_BUILTIN, OUTPUT); // Initialize the LED_BUILTIN pin as an output
WiFi.begin("Wifi-SSID", "Wifi-Password");
Serial.print("Connecting");
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
Serial.println();
Serial.print("Connected, IP address: ");
Serial.println(WiFi.localIP());
}
void loop() {
digitalWrite(LED_BUILTIN, LOW); // Turn the LED on (Note that LOW is the voltage level
// but actually the LED is on; this is because
// it is acive low on the ESP-01)
delay(1000); // Wait for a second
digitalWrite(LED_BUILTIN, HIGH); // Turn the LED off by making the voltage HIGH
delay(2000); // Wait for two seconds (to demonstrate the active low LED)
}
That's all for this step by stpe notes. Hope you are getting something from here! :)
REFERENCE
ESP8266 Wi-Fi Library Great info to get more about ESP8266 Wi-Fi Library as well as what's AP, STA, and BOTH modes.
長久以來，我一直想測試ESP8266，但是一直沒有成功。雖然，網上有很多教學和文章詳細介紹如何使用ESP8266，但即使我跟著很多這些教學一步一步地做，大部份都失敗了。 很多時候無法弄清楚哪裡出了問題，真是令人非常沮喪。 今天我手上的ESP8266已經正常的能回覆 AT Command，所以我趕快把這些步驟寫下來，不只可以提各位讀者參考，以後也可以作為自己的一份筆記。
#include <esp8266wifi.h>
void setup()
{
Serial.begin(115200);
Serial.println();
pinMode(LED_BUILTIN, OUTPUT); // Initialize the LED_BUILTIN pin as an output
WiFi.begin("Wifi-SSID", "Wifi-Password");
Serial.print("Connecting");
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
Serial.println();
Serial.print("Connected, IP address: ");
Serial.println(WiFi.localIP());
}
void loop() {
digitalWrite(LED_BUILTIN, LOW); // Turn the LED on (Note that LOW is the voltage level
// but actually the LED is on; this is because
// it is acive low on the ESP-01)
delay(1000); // Wait for a second
digitalWrite(LED_BUILTIN, HIGH); // Turn the LED off by making the voltage HIGH
delay(2000); // Wait for two seconds (to demonstrate the active low LED)
}
OK，希望你從這裡能得到你要的一些資訊！:)
參考文件：
ESP8266 Wi-Fi Library Great info to get more about ESP8266 Wi-Fi Library as well as what's AP, STA, and BOTH modes.
