Sending array from arduino to of

beginners
#1

Hey Guys,

I am tryng to send an array with values from my Arduino to OF with simple ofSerial functionality and without using firmata.
I am getting data into my app but I am a bit stuck how to handle them.

On arduino I simply send an array like following:

byte serialArrayOne[]  = {1,2,3,4,5,6,7,8};
Serial.write(serialArrayOne,8);

But how do I handle those bytes in OF? How can i convert those bytes back to an array?
Is there somewhere an example to handle more complex serial data in OF?

#2

Check out ofxSerial (also requires https://github.com/bakercp/ofxIO).

Particularly check out the https://github.com/bakercp/ofxSerial/tree/master/example_packet_serial (uses COBS or SLIP encoding to make it easier to mark data packet boundaries) https://github.com/bakercp/ofxSerial/tree/master/example_echo (just shows how to write data and get it back) and https://github.com/bakercp/ofxSerial/tree/master/example_buffered_serial_device (shows how to do basic packet boundary marking using new lines) examples. Each has Arduino code that corresponds to it in the example folder. The source files / examples themselves should be pretty well documented.

If you have any questions or issues, you can leave them at the repo or I’m happy to help here.

#3

Also, in case you want to use the built-in ofSerial with Arduino, I just pushed an example from my class using Arduino / ofSketch (which is just header-only openFrameworks code).

https://github.com/SAIC-ATS/ARTTECH-5010/tree/master/Week_4/SerialFullDuplex

The ofSketch portion will answer your question of reading in and writing arrays from Arduino more directly.

#4

Hey bakercp,

thanks for the fast reply!
I tried the last solution and getting errors while compiling on arduino.
seems the types are not correct. any quick ideas on this?
I tried to convert the String to “const unsigned char” but this didnt workout fine so far.

SerialComSwitch.ino: In function ‘void writeSerialData()’:
SerialComSwitch.ino:59:32: error: invalid conversion from ‘const char*’ to ‘const uint8_t* {aka const unsigned char*}’ [-fpermissive]
In file included from /usr/share/arduino/hardware/arduino/cores/arduino/Stream.h:26:0,
                 from /usr/share/arduino/hardware/arduino/cores/arduino/HardwareSerial.h:28,
                 from /usr/share/arduino/hardware/arduino/cores/arduino/Arduino.h:193,
                 from SerialComSwitch.ino:1:
/usr/share/arduino/hardware/arduino/cores/arduino/Print.h:53:20: error:   initializing argument 1 of ‘virtual size_t Print::write(const uint8_t*, size_t)’ [-fpermissive]
     virtual size_t write(const uint8_t *buffer, size_t size);
#5

Do you have the latest version of Arduino? Could you post your code?

#6

That was the problem. I used the Arduino version of my Distribution. It was to old.
I am now using ofxSerial and the haiku generator. From there I should be able to send the data I like to use.

Thanks!

1 Like
#7

Super! Let me know if you have any questions.

#8

Yes, :smile:

im am sending a string like following from arduino. Thats works fine:

String index = String(1);
String val = String(random(1024));
Serial.print(index + "," + val);
Serial.println("");

But when spliting this to get the single values and put them into a vector I am having segmentation errors.
Here is the collected OF code:

vector<int> values;

values.resize(100);
		for(int i = 0; i < values.size(); i++){
		  values[i] = 0; // set value using index
		}

void ofApp::onSerialBuffer(const ofx::IO::SerialBufferEventArgs& args)
{
    // Buffers will show up here when the marker character is found.
    //SerialMessage message(args.getBuffer().toString(), "", 500);
		vector<string> result = ofSplitString(args.getBuffer().toString(),",");

		if(ofToInt(result[0]) < values.size()){
			if(ofToInt(result[1]) < 1024){
				values[ofToInt(result[0])] = ofToInt(result[1]);
			}
		}

		//cout << values[1] << endl;
    //serialMessages.push_back(message);
}
#9

or maybe you have a better idea to send some values assigned to channels via ofxSerial.

data i want to send:

array[0] = 1024;
array[2] = 1024

and further