ESP-01 - how to build a simple web server using Arduino - part 2 of 2

This is the second part of a 2 parts series on how to build a simple web server using ESP-01 and Arduino. The first part of this post is at http://wei48221.blogspot.tw/2017/06/esp-01-how-to-build-simple-web-server.html.

The Schematics

It's basically the same as that for the previous post except there is a 220 ohm resister and LED attached in series to GPIO2.

Note,

After testing, it's possible to power ESP-01 with the +3V power output from CP-2102. Both the uploading of Arduino sketch to the on-board flash memory of ESP-01 and wifi transmission work correctly.

Arduino Sketch

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#include <ESP8266WiFi.h> #include <ESP8266WebServer.h> ESP8266WebServer server; uint8_t pin_led = 2; // External LED attached to GPIO2 char* ssid = "YOUR_SSID"; char* password = "YOUR_PASSWORD"; void setup() { pinMode(pin_led, OUTPUT); WiFi.mode(WIFI_STA); //We don't want the ESP to act as an AP WiFi.begin(ssid,password); Serial.begin(115200); while(WiFi.status()!=WL_CONNECTED) { Serial.print("."); delay(500); } Serial.println(""); Serial.print("IP Address: "); Serial.println(WiFi.localIP()); server.on("/",[](){server.send(200,"text/plain","Hello World!");}); server.on("/toggle",toggleLED); server.begin(); } void loop() { server.handleClient(); } void toggleLED() { digitalWrite(pin_led,!digitalRead(pin_led)); server.send(204,""); }

Source: https://github.com/acrobotic/Ai_Tips_ESP8266/tree/master/simple_webserver

Note,

- Be sure to replace "YOUR_SSID" and  "YOUR_PASSWORD" with the SSID and the Password for the wireless router used.

- It's important to use "WiFi.mode(WIFI_STA)" to set ESP-01 to act as WiFi client only. If it's not used, ESP-01 will act as both an AP and a WiFi-client when connecting to a WiFi Router and that can mess up other WiFi-devices on your network. 

Procedure for uploading the Arduino Sketch

Be sure to do the following before uploading the sketch to ESP-01.

- Provide external +3.3V to ESP-01 (make sure the +3.3V is connected to VCC, and the GND is connected to GND). Or, power ESP-01 with the +3V power output from CP-2102.

- Plug the CP-2102 module to the USB port of the computer used for firmware upload;

- First close the flash switch then the reset switch so that both GPIO0 and RST of ESP-01 are connected to GND;

- First open the reset switch then the flash switch so that bboth GPIO0 and RST are floating;

- Click on the upload icon to compile and upload the sketch.

Result

After the sketch is uploaded successfully, open Serial Monitor (Tools -> Serial Monitor). If nothing happens, close then open the reset switch to reset ESP-01.

The IP address assigned by the wireless router to ESP-01 will be display in the serial monitor.

Launch a web browser and enter the IP address obtained from the serial monitor of the Arduino IDE.

Enter "192.168.2.19/toggle" to toggle the external attached to GPIO2.

References:

ESP8266 Webserver Step-By-Step Using Arduino IDE (Mac and Windows)
https://www.youtube.com/watch?v=m2fEXhl70OY

Want to blink GPIO2 LED (built in) on ESP8266-01
https://github.com/esp8266/Arduino/issues/2627

How to Use the ESP8266-01 Pins
http://www.instructables.com/id/How-to-use-the-ESP8266-01-pins/