hey there all you brilliant coders
after spending a week figuring out my code wasn't working for lack of a semicolon, i thought i would ask the experts first before hitting my head against the wall trying to figure out i2c....
so what i want to do is take 3 analog joy stick readings from a slave arduino and send them via wire to the master unit
and hopefully export 4 sets of sensor data from the master through the slave via wire then onto my PC via usb
the masters code is rather to long for posting as a hole but the sensor values are 3 digit and can be negative value, tho that could be easily be made positives with a bit of math if sending a negative value turns out to be a pain
luisilva:
You are not using I2C, you are using UART.
and yes UART for the slave to computer component which i know is as easy as using the serial print functions but added to give the reasons why im sending the data
Your code seams good to me, to send 3 values through UART (serial, not I2C - I2C is other thing) to "someone else" it can be a mastar Arduino or a PC or other.
Maybe you can change this:
Serial.print(va3);
Serial.print(" ");
to this:
Serial.println(va3);
This way, you will have each set of values in only one line.
luisilva:
Your code seams good to me, to send 3 values through UART (serial, not I2C - I2C is other thing) to "someone else" it can be a mastar Arduino or a PC or other.
Maybe you can change this:
Serial.print(va3);
Serial.print(" ");
to this:
Serial.println(va3);
This way, you will have each set of values in only one line.
I don't know, I never did that, but I have this 2 examples:
MASTER send:
// Wire Master Writer
// by Nicholas Zambetti <http://www.zambetti.com>
// Demonstrates use of the Wire library
// Writes data to an I2C/TWI slave device
// Refer to the "Wire Slave Receiver" example for use with this
// Created 29 March 2006
// This example code is in the public domain.
#include <Wire.h>
void setup()
{
Wire.begin(); // join i2c bus (address optional for master)
}
byte x = 0;
void loop()
{
Wire.beginTransmission(4); // transmit to device #4
Wire.write("x is "); // sends five bytes
Wire.write(x); // sends one byte
Wire.endTransmission(); // stop transmitting
x++;
delay(500);
}
SLAVE receive:
// 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.
#include <Wire.h>
void setup()
{
Wire.begin(4); // join i2c bus with address #4
Wire.onReceive(receiveEvent); // register event
Serial.begin(9600); // start serial for 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
}
The main difference from your code to this code is that you "don't care about" the Wire.available(). You see that you have 1 byte to read, and then "don't careening about for that" you read 4 bytes. I think that don't makes sense.
while(1 < Wire.available());
{
int temp = Wire.read();
Serial.print(temp);
Serial.print(", ");
int xaxis = Wire.read();
Serial.print(xaxis);
Serial.print(", ");
int yaxis = Wire.read();
Serial.print(yaxis);
Serial.print(", ")
int depth = Wire.read();
Serial.println(depth);
}
There is the code of the example:
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
The code of the example only receive the exact amount of bytes, because it is repeated while there are bytes to be received:
while (1 < Wire.available()) // loop through all but the last
But you, don't care about that.
One thing even worst, that only now I see, is that you are stopping your code while you have someting to receive:
while(1 < Wire.available());
(this ' ; ' is telling to "do nothing" while it have bytes to receive)
And then you go read all the bytes (after they are lost).
In your place, I will do something like:
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
Serial.print(", ");
}
int x = Wire.read(); // receive byte as an integer
Serial.println(x); // print the integer
}
Note that you don't need to call the variables exactly what hold. It can be called c but hold one temperature, and the next time the loop repeats the same c can hold the xaxis.
ok so im about half way through a video on you tube and im beginning to see who this works better
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
Serial.print(", ");
}
int x = Wire.read(); // receive byte as an integer
Serial.println(x); // print the integer
}
so this should list the data something like
23,44,55,66,88
23,44,55,66,88
23,44,55,66,88
am i correct ?
char c = Wire.read(); // receive byte as a character
Serial.print(c); // print the character
Serial.print(", ");
You read one char at a time, and print it to the screen, followed by a comma and space.
23,44,55,66,88
Your sample has two chars and a space, so given the same code, no, that would be impossible. If c is defined as an int (or cast as one when being sent to serial print), then it's possible to have multi-character numbers, because Serial print will convert 0x17 (Decimal 23) to '2' followed by '3'.
char c = Wire.read(); // receive byte as a character
Serial.print(c); // print the character
Serial.print(", ");
You read one char at a time, and print it to the screen, followed by a comma and space.
23,44,55,66,88
Your sample has two chars and a space, so given the same code, no, that would be impossible. If c is defined as an int (or cast as one when being sent to serial print), then it's possible to have multi-character numbers, because Serial print will convert 0x17 (Decimal 23) to '2' followed by '3'.
makes perfect sense also means all int values will need to be between 0 and 255 if im not mistaken
