I’m pretty much a novice in arduino code and I’m having trouble with the following code. When I compile it with arduino 0022 there are no errors. If I access the Ethernet shield I see the HTML page fine. The troubles come with that the link to the video I want to post in the code. I’m able to see the frame but the link doesn’t ever come up. within that frame all I see is the HTML page that has been created. Is there a chance that there’s an error in the code or HTML formatting? Is there a specific Library I need to use? thanks in advance for the help!
#include <SPI.h>
#include <Client.h>
#include <Ethernet.h>
#include <Server.h>
#include <Udp.h>
#include <Servo.h>
char Link[]= "http://www.anywebsite.com"; //video link
Servo tilt;
Servo pan;
int panpos = 90;
int tiltpos = 90;
byte mac[] = { 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF }; //physical mac address
byte ip[] = { 192, 128, 13, 169 }; // ip in lan
byte gateway[] = { 192, 128, 13,1 }; // internet access via router
byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
Server server(80); //server port
String readString = String(30); //string for fetching data from address
void setup(){
Ethernet.begin(mac, ip, gateway, subnet);
Serial.begin(9600);
tilt.attach(3);
pan.attach(9);
tilt.write(90);
pan.write(90);
}
void loop(){
// Create a client connection
Client 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 (c == '\n') {
if (readString.indexOf("?") <0)
{
//do nothing
}
else
{
if(readString.indexOf("UP=UP") >0)
{
movetiltupstep();
}
else if(readString.indexOf("DN=DN") >0)
{
movetiltdownstep();
}
else if(readString.indexOf("LT=LT") >0)
{
movepanleftstep();
}
else if(readString.indexOf("RT=RT") >0)
{
movepanrightstep();
}
else if(readString.indexOf("CN=CN") >0)
{
center();
}
}
// now output HTML data starting with standard header
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println();
//set background to green
client.print("<body style=background-color:blue>");
client.println("<hr />");
client.println("<center>");
client.println("<h1>Camera control</h1>");
client.println("<form method=get name=SERVO>");
client.println("<input type=submit value=UP name=UP style=\"width:100px\"><br>");
client.println("<input type=submit value=LT name=LT style=\"width:100px\"><input type=submit value=CN name=CN style=\"width:100px\"><input type=submit value=RT name=RT style=\"width:100px\"><br>");
client.println("<input type=submit value=DN name=DN style=\"width:100px\">");
client.println("<hr />");
client.println("<iframe width= 640 height= 360 src= Link[]frameborder= 0 allowfullscreen></iframe>");
client.println("</form>");
client.println("</center>");
client.println("</body></html>");
//clearing string for next read
readString="";
//stopping client
client.stop();
}
}
}
}
}
void movetiltupstep(){
tiltpos = tilt.read();
Serial.println(tiltpos);
if (tiltpos >= 66)
{
tilt.write(tiltpos - 2);
}
}
void movetiltdownstep(){
tiltpos = tilt.read();
Serial.println(tiltpos);
if (tiltpos <= 116)
{
tilt.write(tiltpos + 2);
}
}
void movepanleftstep(){
panpos = pan.read();
Serial.println(panpos);
if (panpos >= 4)
{
pan.write(panpos - 4);
}
}
void movepanrightstep(){
panpos = pan.read();
Serial.println(panpos);
if (panpos <= 176)
{
pan.write(panpos + 4);
}
}
void center(){
panpos = pan.read();
tiltpos = tilt.read();
Serial.println(panpos);
if (panpos < 90)
{
for(int i = panpos; i <= 90; i++) {
pan.write(i);
}
}
else if (panpos > 90)
{
for(int i = panpos; i >= 90; i--) {
pan.write(i);
}
}
if (tiltpos < 90)
{
for(int i = tiltpos; i <= 90; i++) {
tilt.write(i);
}
}
else if (tiltpos > 90)
{
for(int i = tiltpos; i >= 90; i--) {
tilt.write(i);
}
}
}
Yes, actually, your code cannot work. Let’s put appart the wrong formatting of the line (“Link[]” which is concatenated to “frameborder”), the page that should start with <html>, that you are lucky to be in a very specific case where the Content-Length header is not required and so on, and let’s focus on what you tried to do.
You tried to do what is called a variable interpolation: you assumed that the variable name “Link[]” in the string will be replaced by another string. It is something that does not exist in C or C++.
There are several way to do what you want (you can take a look at the String class which exists since Arduino-019 http://arduino.cc/en/Reference/StringObject and what is called concatenation http://arduino.cc/en/Reference/StringConcat).
In your case, you can simply do that (not tested, but should explain the trick):
It is less beautiful than what you wanted to do, but it is enough for what you need.