Line Graph in Processing?

Forum 2005-2010 (read only) Software Interfacing
1

Hi, I have a device that outputs a voltage in the mV range (0-1V), and I want to connect this up to the Arduino, and have it plot a time vs voltage line graph using Processing. Problem is, I am not very good at coding in Processing, and haven't been able to find any line graph examples.

Can anyone help me out here?

-Dan :slight_smile:

2

It's not all that difficult. There is a line function in Processing.

Do you want the graph to function like an oscilloscope, where the data being shown is the last n seconds/minutes/hours worth of data?

Do you have some code on the Arduino that sends the data to the serial port? In what format?

Do you have the start of a Processing application that connects to the serial port? Are you collecting the data already? Parsing it?

3

Basically, I just want a graph that receives the voltage in millivolts, from one of the Arduinos inputs, and plot it on a graph, with time being on the X axis, and voltage on Y.

So, I could have it poll the Arduino for a reading every second or so, it would plot that point on the graph, then connect it up with a line (Or just use a line instead of a point)

int val = 0;
void setup() {
   // initialize the serial communication:
   Serial.begin(9600);
 }
 void loop() {
   
     val = analogRead(5);
    Serial.println(val);
   delay(1000);
 }

Thats the current code, though I need to map the output from 0 -1023 to a voltage .

4

There is a nice Processing plotter sketch here: Hobby Robotics » Realtime Graphing of Accelerometer/Gyroscope Data

5

Thanks for that mem, exactly what I wanted, after I add some scales :slight_smile:

6

I'm not sure how common it is, but I've used OpenOffice.org suite to graph some incoming data before.

You can either save the data into eeprom, or send it to serial, or a SD card of course. Then copy the text, save it to a .CSV file, then it gives you some settings for how you want it spaced and such, then it creates a table.

From there, you can create a graph by clicking, the graph button! lol :slight_smile: Can use pie graphs.. bar graphs.. some graphs I've never even heard of! I've only used it twice (for testing) so I'm not too familiar with it, but it worked fairly well.