Hi,
I don't know programming.
I have a working webserver sketch (found on internet) for an arduino uno + ethernet shield, and a 9V DC adapter. The problem is that when the mains power is down (power outage) and then back on, the webserver is not working anymore. I have to unplug the adapter from the mains then plug it back, for a few times, for the webserver to start running again and be able to access the webpage it serves.
Is it possible to run some self check code and if webserver is not running then reset the board until it works? What would be the code for that?
This is the sketch I'm using:
#include <SPI.h>
#include <Ethernet.h>
byte mac[] = { 0xDE, 0xA2, 0xDA, 0x00, 0x2B, 0x7D }; // MAC address
IPAddress ip(10,77,80,15); // IP address
EthernetServer server(80);
char char_in = 0; // used to store a character from the Ethernet port
String HTTP_req; // stores the received HTTP request
const byte LED_pins[] = {2, 3}; // Arduino pins used as ouputs for LEDs
byte LED[sizeof(LED_pins)] = {0}; // the state of each LED
void setup()
{
Ethernet.begin(mac, ip);
server.begin();
// set up the LED pins as outputs
for (byte index = 0; index < sizeof(LED_pins); index++) {
pinMode(LED_pins[index], OUTPUT);
}
}
void loop()
{
EthernetClient client = server.available();
if (client) {
while (client.connected()) {
if (client.available()) {
char_in = client.read(); // get a single character from the Ethernet port
HTTP_req += char_in; // build a string out of the received characters
// answer first HTTP request immediately
if (char_in == '\n') {
// respond to HTTP request
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println();
CheckLEDs(); // get state of LED checkboxes from web page
DisplayLEDs(&client); // display checkboxes on web & write to LEDs
HTTP_req = ""; // delete string contents
client.stop();
} // end if (char_in == '\n')
} // end if (client.available()
} // end while (client.connected())
} // end if (client)
}
// get the state of the LED checkboxes from the HTTP request
void CheckLEDs()
{
for (byte led_num = 0; led_num < sizeof(LED_pins); led_num++) {
if ((HTTP_req.charAt(9) == (LED_pins[led_num] + '0')) &&
(HTTP_req.charAt(16) == (LED_pins[led_num] + '0'))) { // LED box is checked
LED[led_num] = 1;
}
else if (HTTP_req.charAt(9) == (LED_pins[led_num] + '0')) { // LED box is unchecked
LED[led_num] = 0;
}
}
}
// write the HTML that includes the state of the LED checkboxes for displaying on the web browser
void DisplayLEDs(Client *client)
{
// some CSS in the HTML to change colours and position of the box containing the LED checkboxes
client->print("<div style=\"background:white; color:green; position: absolute; margin:20px; border: grey solid 2px; padding:0 10px 4px 10px;\">");
client->print("<h1 style=\"font: normal 20px/150% Verdana, Arial, Sans-serif;\">TEST</h1>");
// send each LED checkbox in turn
for (byte led_num = 0; led_num < sizeof(LED_pins); led_num++) {
// use hidden checkbox so that unchecking a checkbox sends a value to the Arduino
// if only a normal checkbox is used, nothing is sent when it is unchecked
// both hidden and normal checkboxes are produced here for each LED
client->print("<form> <input type=\"hidden\" name=\"LED");
client->print(LED_pins[led_num], DEC);
client->print("\" value=\"0\"> <input type=\"checkbox\" name=\"LED");
client->print(LED_pins[led_num], DEC);
client->print("\" value=\"");
client->print(LED_pins[led_num], DEC);
client->print("\"");
// write to the LED connected to the Arduino board
if (LED[led_num]) {
client->print(" checked "); // part of HTML if checkbox is to be displayed checked
digitalWrite(LED_pins[led_num], HIGH); // switch LED on
}
else {
digitalWrite(LED_pins[led_num], LOW); // switch LED off
}
client->print(" onclick=\"submit();\">LED");
client->print(LED_pins[led_num], DEC);
client->print(" </form>"); // end of HTML for 1 LED's form
}
client->print("</div>"); // end of box containing LEDs
}
