Below is some test code you might try if you know you have a good file on your sd card. I've noticed that under some conditions the sd card may become unaccessable and require the card to be removed and reinserted or the arduino cold booted with the card in it to regain access to the sd card.
//zoomkat 12/26/12
//SD server test code
//open serial monitor to see what the arduino receives
//address will look like http://192.168.1.102:84 when submited
//for use with W5100 based ethernet shields
#include <SD.h>
#include <SPI.h>
#include <Ethernet.h>
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
byte ip[] = { 192, 168, 1, 102 }; // ip in lan
byte gateway[] = { 192, 168, 1, 1 }; // internet access via router
byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
EthernetServer server(84); //server port
String readString;
//////////////////////
void setup(){
Serial.begin(9600);
// disable w5100 while setting up SD
pinMode(10,OUTPUT);
digitalWrite(10,HIGH);
Serial.print("Starting SD..");
if(!SD.begin(4)) Serial.println("failed");
else Serial.println("ok");
Ethernet.begin(mac, ip, gateway, gateway, subnet);
digitalWrite(10,HIGH);
//delay(2000);
server.begin();
Serial.println("Ready");
}
void loop(){
// Create a client connection
EthernetClient client = server.available();
if (client) {
while (client.connected()) {
if (client.available()) {
char c = client.read();
//read char by char HTTP request
if (readString.length() < 100) {
//store characters to string
readString += c;
//Serial.print(c);
}
//if HTTP request has ended
if (c == '\n') {
///////////////
Serial.println(readString); //print to serial monitor for debuging
client.println("HTTP/1.1 200 OK"); //send new page
client.println("Content-Type: text/html");
//client.println("Content-Type: image/jpeg");
//client.println("Content-Type: image/gif");
//client.println("Content-Type: application/x-javascript");
//client.println("Content-Type: text");
client.println();
//File myFile = SD.open("boom.htm");
File myFile = SD.open("HYPNO.JPG");
//File myFile = SD.open("BLUEH_SL.GIF");
//File myFile = SD.open("SERVOSLD.HTM");
if (myFile) {
//Serial.println("test.txt:");
// read from the file until there's nothing else in it:
while (myFile.available()) {
client.write(myFile.read());
}
// close the file:
myFile.close();
}
delay(1);
//stopping client
client.stop();
readString="";
//}
}
}
}
}
}