osctools/csvrandomwriter/csvrandomwriter.pde

Table table;

float frequency=4; //data frequency in Hz
int duration=10; //in s

void setup() {
  table = new Table();
  table.addColumn("time"); // in milliseconds
  table.addColumn("heartrate");
  table.addColumn("random");
  
  for (int i=0;i<(int)(duration*frequency);i++) {
    TableRow newRow = table.addRow();
    newRow.setFloat("time", (float)(i/frequency));
    newRow.setFloat("heartrate", noise(i/10)*40.0+60);
    newRow.setFloat("random", random(1));
  }
  
  saveTable(table, "data.csv");
  println("Finished");
}