I want to be able to wireless control a single IO pin on an ESP8266 using a java app I wrote on a PC. I've been able to successfully do it by sending a single UDP packet from the app over a wired network, receiving it using an UNO with an Ethernet shield, where my home router is the default gateway for the communication, but can anybody think of a way to simply send the packet from my computer directly to the 8266 module, without the router involved? I thought of using an iPhone as a virtual router (hotspot with the computer and the 8266 connected), but I believe it will firewall any communication between the two tethered devices. I've scoured the net, but everything I can find involves a router in between the two devices. Any help or advice on this would be appreciated.
"I've scoured the net, but everything I can find involves a router in between the two devices. Any help or advice on this would be appreciated."
The below code from the IDE examples operates as an access point that has a web server. You log into the AP then connect to the server. I think there are other example AP/servers.
/*
Copyright (c) 2015, Majenko Technologies
All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.
* * Neither the name of Majenko Technologies nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Create a WiFi access point and provide a web server on it. */
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#ifndef APSSID
#define APSSID "ESP8266-ZK"
#define APPSK "zoomkat"
#endif
/* Set these to your desired credentials. */
const char *ssid = APSSID;
const char *password = APPSK;
ESP8266WebServer server(80);
/* Just a little test message. Go to http://192.168.4.1 in a web browser
connected to this access point to see it.
*/
void handleRoot() {
server.send(200, "text/html", "<h1>You are connected</h1>");
Serial.println("Got a client!"); //added so see client connect
}
void setup() {
delay(1000);
Serial.begin(115200);
Serial.println();
Serial.print("Configuring access point...");
/* You can remove the password parameter if you want the AP to be open. */
WiFi.softAP(ssid);
// by default the local IP address of will be 192.168.4.1
// you can override it with the following:
// WiFi.config(IPAddress(10, 0, 0, 1));
IPAddress myIP = WiFi.softAPIP();
Serial.print("AP IP address: ");
Serial.println(myIP);
server.on("/", handleRoot);
server.begin();
Serial.println("HTTP server started");
}
void loop() {
server.handleClient();
}
If you want to connect two devices of the same type in Ethernet you need a crossover cable. And you will need to configure your devices to have fixed IP addresses. When you remove the router which usually has additional functions like DHCP services the devices will no longer be able to get an IP address.
I believe there are Ethernet devices that have automatic crossover build in. But this is unlikely true for the Arduino boards. So, you can try a patch cable between your PC and your Arduino if you do not have a crossover cable at hand and hope your PC detects that automatically.
Below is some example code I modified from being connected via wifi to a router, to being a stand alone access point with the web server. Fairly simple up top copy/paste operation to change from a LAN server to an AP server, with the rest remaining the same.
/*
WiFi Web Server LED Blink
A simple web server that lets you blink an LED via the web.
This sketch will print the IP address of your WiFi Shield (once connected)
to the Serial monitor. From there, you can open that address in a web browser
to turn on and off the LED on pin 5.
If the IP address of your shield is yourAddress:
http://yourAddress/H turns the LED on
http://yourAddress/L turns it off
This example is written for a network using WPA encryption. For
WEP or WPA, change the Wifi.begin() call accordingly.
Circuit:
by Tom Igoe
ported for sparkfun esp32
31.01.2017 by Jan Hendrik Berlin
WiFi shield attached
LED attached to pin 5
created for arduino 25 Nov 2012
*/
//#include <WiFi.h> //ESP32
#include <ESP8266WiFi.h>
// Replace with your network credentials
const char* ssid = "ESP8266-AP-LED";
const char* password = "zoomkat";
WiFiServer server(80);
void setup()
{
Serial.begin(115200);
pinMode(D9, OUTPUT); // set the onboard LED pin mode
delay(10);
// Start AP Wi-Fi network with SSID and password
Serial.println();
Serial.println();
Serial.print("Setting AP (Access Point)…");
// Remove the password parameter, if you want the AP (Access Point) to be open
WiFi.softAP(ssid, password);
IPAddress IP = WiFi.softAPIP();
Serial.print("AP IP address: ");
Serial.println(IP);
server.begin();
}
int value = 0;
void loop() {
WiFiClient client = server.available(); // listen for incoming clients
if (client) { // if you get a client,
Serial.println("New Client."); // print a message out the serial port
String currentLine = ""; // make a String to hold incoming data from the client
while (client.connected()) { // loop while the client's connected
if (client.available()) { // if there's bytes to read from the client,
char c = client.read(); // read a byte, then
Serial.write(c); // print it out the serial monitor
if (c == '\n') { // if the byte is a newline character
// if the current line is blank, you got two newline characters in a row.
// that's the end of the client HTTP request, so send a response:
if (currentLine.length() == 0) {
// HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
// and a content-type so the client knows what's coming, then a blank line:
client.println("HTTP/1.1 200 OK");
client.println("Content-type:text/html");
client.println();
// the content of the HTTP response follows the header:
client.print("Click <a href=\"/H\">here</a> to turn the LED on pin 9 off.
");
client.print("Click <a href=\"/L\">here</a> to turn the LED on pin 9 on.
");
// The HTTP response ends with another blank line:
client.println();
// break out of the while loop:
break;
} else { // if you got a newline, then clear currentLine:
currentLine = "";
}
} else if (c != '\r') { // if you got anything else but a carriage return character,
currentLine += c; // add it to the end of the currentLine
}
// Check to see if the client request was "GET /H" or "GET /L":
if (currentLine.endsWith("GET /H")) {
digitalWrite(D9, HIGH); // GET /H turns the LED on
}
if (currentLine.endsWith("GET /L")) {
digitalWrite(D9, LOW); // GET /L turns the LED off
}
}
}
// close the connection:
client.stop();
Serial.println("Client Disconnected.");
}
}