Below is a quick review of the NodeMCU v1.0 Dev Kit board microcontroller that can be picked up for under $10. NodeMCU is an open-source IoT platform based on the ESP8266 Wi-Fi SoC.

Specs:

I ordered 1x Node MCU v1.0 with Free delivery from eBay seller 19star-au for $10.94.

I have played with Arduinos and having Wifi in a small microcontroller by default is appealing.

How to program your NodeMCU

1. Goto www.arduino.cc and download the Arduino IDE (1.8.x or higher).
2. Open the Arduino IDE and find the Preferences Menu
3. Paste the following in the “Additional Boards Manager” textbbox: http://arduino.esp8266.com/stable/package_esp8266com_index.json
4. Goto Tools, Boards*, Boards manager and search for “esp8266” and install it.
5. Close your Arduino IDE and reopen it.
6. Now choose your board type in the Arduino IDE (Tools, Board, Node MCU, 1.0 ESP-12E..)

You will not be able to select a sample script (e.g Blink) by navigating to File, Examples, ESP8266, Blink.

The Blink code will look like this:

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);     // Initialize the LED_BUILTIN pin as an output
}

// the loop function runs over and over again forever
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 active 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)
}

You can now plug the ESP8266 in and try compile and upload the new sketch to the device.

Mac Troubleshooting: If the Arduino IDE says you do not have a serial port you may need to download the USB-Serial driver from silabs.

If all goes well you will have a blinking light on your ESP8266.

Now lets try the web server sketch

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>

const char* ssid = "yourwifinetwork";
const char* password = "yourwifipassword";

ESP8266WebServer server(80);

const int led = 13;

void handleRoot() {
  digitalWrite(led, 1);
  server.send(200, "text/plain", "hello from esp8266!");
  digitalWrite(led, 0);
}

void handleNotFound(){
  digitalWrite(led, 1);
  String message = "File Not Found\n\n";
  message += "URI: ";
  message += server.uri();
  message += "\nMethod: ";
  message += (server.method() == HTTP_GET)?"GET":"POST";
  message += "\nArguments: ";
  message += server.args();
  message += "\n";
  for (uint8_t i=0; i<server.args(); i++){
    message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
  }
  server.send(404, "text/plain", message);
  digitalWrite(led, 0);
}

void setup(void){
  pinMode(led, OUTPUT);
  digitalWrite(led, 0);
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  Serial.println("");

  // Wait for connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

  if (MDNS.begin("esp8266")) {
    Serial.println("MDNS responder started");
  }

  server.on("/", handleRoot);

  server.on("/inline", [](){
    server.send(200, "text/plain", "this works as well");
  });

  server.onNotFound(handleNotFound);

  server.begin();
  Serial.println("HTTP server started");
}

void loop(void){
  server.handleClient();
}

A quick check of my routers DHCP list and I found the ESP8266 listening for web requests at 192.168.1.110.

More to come….

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