I'm working on a new project. For getting my data I would like to read serial data given by a commercial measurement device. As far as I know I do have to use a MAX232 to change the +-12V-RS232-signal to a TTL-signal.
Nevertheless I do have to find a specific number in each line for my analysis - I have marked these numbers bold in the table above. Do you see any possibility to find the number in the string (between "%" and "xyz")?
If I would get this string, I could convert it by "int()" and average or display the numbers.
I would not use the String class or serial event to input the data. I would use the techniques from serial input basics to read and parse the data. Using the example that uses strtok you can break down the data and pull what you want out, use the atoi() function to turn string data to integers or atof() to get floats.
Thank you very much for this hint! I have tried to use the example for reading serial data, to convert the string to a char-array and to break the data afterwards:
String inputString = ""; // a string to hold incoming data
boolean stringComplete = false; // whether the string is complete
int measurement_int = 0;
void setup() {
// initialize serial:
Serial.begin(9600);
// reserve 80 bytes for the inputString:
inputString.reserve(80);
}
void loop() {
// print the string when a newline arrives:
if (stringComplete) {
Serial.println(inputString);
char * strtokIndx; // this is used by strtok() as an index
strtokIndx = strtok(inputStringChar," ");// get the first part
strtokIndx = strtok(NULL," ");// get the second part
strtokIndx = strtok(NULL," ");// get the third part
strtokIndx = strtok(NULL," ");// get the fourth part
strtokIndx = strtok(NULL," ");// get the fifth part
strtokIndx = strtok(NULL," ");// get the sixth part
strtokIndx = strtok(NULL," ");// get the seventh part
measurement_int = atoi(strtokIndx);//converts data to integer
Serial.println(measurement_int);
// clear the string:
inputString = "";
stringComplete = false;
}
}
void serialEvent() {
while (Serial.available()) {
// get the new byte:
char inChar = (char)Serial.read();
// add it to the inputString:
inputString += inChar;
// if the incoming character is a newline, set a flag
// so the main loop can do something about it:
if (inChar == '\n') {
stringComplete = true;
char inputStringChar[] = ""; //creates a new empty char-array
inputStringChar[] = char(inputString); //converts string to char-array
}
}
}
When compiling I to get an error:
avr-g++: error: missing filename after '-o'
exit status 1
Error compiling.
First of all I thought, that I would have done an error - but even the presented example of a "SerialEvent" does cause the same error.
Can you identify the problem?
char inputStringChar[] = ""; //creates a new empty char-array
inputStringChar[] = char(inputString); //converts string to char-array
To convert String to string
add char inputStringChar[50]; as a global variable and replace the above 2 lines with
inputString.toCharArray(inputStringChar, 50);
50 character buffer gives a bit of headroom. Code compiles and works for me with above changes using Ver. 1.04.
I would recommend getting rid of the String class altogether and using the c-array techniques presented by Robin2 in the serial input basics posts.
String inputString = ""; // a string to hold incoming data
boolean stringComplete = false; // whether the string is complete
int measurement_int = 0;
char inputStringChar[50];
void setup()
{
// initialize serial:
Serial.begin(9600);
// reserve 80 bytes for the inputString:
inputString.reserve(80);
}
void loop()
{
// print the string when a newline arrives:
if (stringComplete) {
Serial.println(inputString);
char * strtokIndx; // this is used by strtok() as an index
strtokIndx = strtok(inputStringChar," ");// get the first part
strtokIndx = strtok(NULL," ");// get the second part
strtokIndx = strtok(NULL," ");// get the third part
strtokIndx = strtok(NULL," ");// get the fourth part
strtokIndx = strtok(NULL," ");// get the fifth part
strtokIndx = strtok(NULL," ");// get the sixth part
strtokIndx = strtok(NULL," ");// get the seventh part
measurement_int = atoi(strtokIndx);//converts data to integer
Serial.println(measurement_int);
// clear the string:
inputString = "";
stringComplete = false;
}
}
void serialEvent()
{
while (Serial.available())
{
// get the new byte:
char inChar = (char)Serial.read();
// add it to the inputString:
inputString += inChar;
// if the incoming character is a newline, set a flag
// so the main loop can do something about it:
if (inChar == '\n')
{
stringComplete = true;
inputString.toCharArray(inputStringChar, 50);
}
}
}
first of all thank you very much for this kind help! Unfortunately I have to leave to Cape town for the next few days, so I will have to test your hints after my return of the journey.
thank you very much, the code runs very well now and the data is collected properly!
I will save the link to the "Serial input basics" - they will be very usefull somewhen!!
@ sterretje: Thank you very much for the offer to meet! I have only had some days in Cape Town at a conference and had to go home directly afterwards again..
So it depends on where you are 