Hi, i made a sketct but it doesn't work flawless. In the code i state if x==255 then the led needs to burn, it does that but when the value gets lower again (under 255) then the led stays on. I made sure that the led couldnt get a 255 reading by turning the potentiometer which simulates a sensor al the way down to 0 so there's no posibility it will read 255.
Setup: i have 2 arduino's wired togheter true I2c (master slave) the master has an ethernetshield 2 ontop of it which send out een webserver from the SD card (the html page is on the SD card) which shows the 3 potentiometer values on the webserver. I wired the potentiometers to A0, A1 and A2 the reads are directly sended over I2c to the slave which reads the data and lights a led when a value of 255 is reached (highest read possible).
here is the code of the arduino with the ethernetshield (master)
#include <SPI.h>
#include <Ethernet2.h>
#include <SD.h>
#include <Wire.h>
// size of buffer used to capture HTTP requests
#define REQ_BUF_SZ 50
// MAC address from Ethernet shield sticker under board
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(10, 10, 2, 143); // IP address, may need to change depending on network
EthernetServer server(80); // create a server at port 80
File webFile; // the web page file on the SD card
char HTTP_req[REQ_BUF_SZ] = {0}; // buffered HTTP request stored as null terminated string
char req_index = 0; // index into HTTP_req buffer
int X = 0;
int Y = 0;
int Z = 0;
//const int ss = 53;
void setup()
{
Wire.begin();
//pinMode(53, OUTPUT);
/* disable Ethernet chip
pinMode(10, OUTPUT);
digitalWrite(10, HIGH);*/
Serial.begin(9600); // for debugging
// initialize SD card
Serial.println("Initializing SD card...");
if (!SD.begin(4)) {
Serial.println("ERROR - SD card initialization failed!");
return; // init failed
}
Serial.println("SUCCESS - SD card initialized.");
// check for index.htm file
if (!SD.exists("index.htm")) {
Serial.println("ERROR - Can't find the index.htm file!");
return; // can't find index file
}
Serial.println("SUCCESS - Found index.htm file.");
Ethernet.begin(mac, ip); // initialize Ethernet device
server.begin(); // start to listen for clients
}
void loop()
{
X = analogRead(A0);
Wire.beginTransmission(8); // transmit to device #8
Wire.write("X is ");
Wire.write(X/4);
Wire.endTransmission(); // stop transmitting
Serial.println(X);
Y = analogRead(A1);
Wire.beginTransmission(8); // transmit to device #8
Wire.write("Y is ");
Wire.write(Y/4);
Wire.endTransmission(); // stop transmitting
Serial.println(Y);
Z = analogRead(A2);
Wire.beginTransmission(8); // transmit to device #8
Wire.write("Z is ");
Wire.write(Z/4);
Wire.endTransmission(); // stop transmitting
Serial.println(Z);
EthernetClient client = server.available(); // try to get client
if (client) { // got client?
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) { // client data available to read
char c = client.read(); // read 1 byte (character) from client
// buffer first part of HTTP request in HTTP_req array (string)
// leave last element in array as 0 to null terminate string (REQ_BUF_SZ - 1)
if (req_index < (REQ_BUF_SZ - 1)) {
HTTP_req[req_index] = c; // save HTTP request character
req_index++;
}
// last line of client request is blank and ends with \n
// respond to client only after last line received
if (c == '\n' && currentLineIsBlank) {
// send a standard http response header
client.println("HTTP/1.1 200 OK");
// remainder of header follows below, depending on if
// web page or XML page is requested
// Ajax request - send XML file
if (StrContains(HTTP_req, "ajax_inputs")) {
// send rest of HTTP header
client.println("Content-Type: text/xml");
client.println("Connection: keep-alive");
client.println();
// send XML file containing input states
XML_response(client);
}
else { // web page request
// send rest of HTTP header
client.println("Content-Type: text/html");
client.println("Connection: keep-alive");
client.println();
// send web page
webFile = SD.open("index.htm"); // open web page file
if (webFile) {
while (webFile.available()) {
client.write(webFile.read()); // send web page to client
}
webFile.close();
}
}
// display received HTTP request on serial port
Serial.print(HTTP_req);
// reset buffer index and all buffer elements to 0
req_index = 0;
StrClear(HTTP_req, REQ_BUF_SZ);
break;
}
// every line of text received from the client ends with \r\n
if (c == '\n') {
// last character on line of received text
// starting new line with next character read
currentLineIsBlank = true;
}
else if (c != '\r') {
// a text character was received from client
currentLineIsBlank = false;
}
} // end if (client.available())
} // end while (client.connected())
delay(1); // give the web browser time to receive the data
client.stop(); // close the connection
} // end if (client)
}
// send the XML file with switch statuses and analog value
void XML_response(EthernetClient cl)
{
int analog_val1;
int analog_val2;
int analog_val3;
cl.print("<?xml version = \"1.0\" ?>");
cl.print("<inputs>");
cl.print("<button1>");
analog_val1 = analogRead(1);
cl.print("<analog1>");
cl.print(analog_val1);
cl.print("</analog1>");
cl.print("</button1>");
cl.print("<button2>");
analog_val2 = analogRead(2);
cl.print("<analog2>");
cl.print(analog_val2);
cl.print("</analog2>");
cl.print("</button2>");
cl.print("<button3>");
analog_val3 = analogRead(3);
cl.print("<analog3>");
cl.print(analog_val3);
cl.print("</analog3>");
cl.print("</button3>");
cl.print("</inputs>");
}
// sets every element of str to 0 (clears array)
void StrClear(char *str, char length)
{
for (int i = 0; i < length; i++) {
str[i] = 0;
}
}
// searches for the string sfind in the string str
// returns 1 if string found
// returns 0 if string not found
char StrContains(char *str, char *sfind)
{
char found = 0;
char index = 0;
char len;
len = strlen(str);
if (strlen(sfind) > len) {
return 0;
}
while (index < len) {
if (str[index] == sfind[found]) {
found++;
if (strlen(sfind) == found) {
return 1;
}
}
else {
found = 0;
}
index++;
}
return 0;
}
This is the code for the slave
// Wire Slave Receiver
// by Nicholas Zambetti <http://www.zambetti.com>
// Demonstrates use of the Wire library
// Receives data as an I2C/TWI slave device
// Refer to the "Wire Master Writer" example for use with this
// Created 29 March 2006
// This example code is in the public domain.
int LED = 46;
#include <Wire.h>
void setup() {
Wire.begin(8); // join i2c bus with address #8
Wire.onReceive(receiveEvent); // register event
Serial.begin(9600); // start serial for output
pinMode(LED, OUTPUT);
}
void loop() {
delay(100);
}
// function that executes whenever data is received from master
// this function is registered as an event, see setup()
void receiveEvent(int howMany) {
while (1 < Wire.available()) { // loop through all but the last
char c = Wire.read(); // receive byte as a character
Serial.print(c); // print the character
}
int x = Wire.read(); // receive byte as an integer
Serial.println(x); // print the integer
if (x == 255) {
digitalWrite(LED, HIGH);
delay(5000);
return;
}
}
Does anyone have an explanation why the leds keeps burning after it read 255 once? If i pres reset then the led is turned of and i can do another reading, but what i want to do is when it reads 255 from the I2c bus it needs to light up and otherwise turn low again and wait for the next 255 reading. Hope someone could help me with this problem.
