Signal Noise

[Golto]

I don't know how useful this info will be, but I was able to graph out signal noise across a couple KOP sensors.

The hardware was tested on an Arduino Diecimilia, Analog port 0, the code will be posted later. I also used a program called Gobeteeno to assist in logging the data. Then in Excel I manipulated the data and generated a graph. The data was taken over 100 samples 1/10 of a second apart.

The sensors tested were the 2009 KOP 3-axis Accelerometer and the 2010 KOP Gyro, rate and temp. The graphs are attached as a .zip, inside are the PDFs generated.

INSTRUCTIONS:

1. Download Betweeno from http://mikmo.dk/gobetwino.html
2. Consulting documentation, add a process for EXCEL in Gobetwino
3. program the arduino with the following code
4. start gobetwino
5. press reset on the Arduino
6. watch as the data populates!

/*****************************
 * ANALOG SENSOR NOISE TEST  *
 * 2010 Patrick Plude        *
 *****************************/
 
// some setup variables
int serInLen = 25;
char serInString[25];
int pId =0;
int result;

void setup() 
{ 
  Serial.begin(9600); 
  Serial.println("#S|EXCEL|[]#");        // start EXCEL
  readSerialString(serInString, 5000);  // wait  5  seconds (max) for answer from Gobetwino (=porcess ID)
  pId= atoi(serInString);               // convert result to integer 
  sendAnalogValues();                       // send some data to Excell
} 
 
void loop() 
{ 
  // no code here, all carried out in subroutines!
} 

void sendAnalogValues() 
{
   char buffer[5];
   int sensorValue;
   
   for (int i=1; i<=100; i++){
     //Read the sensor values
     sensorValue=analogRead(0);
  
    //Send the values as though it was typed into Excell, using the SENDK command
    // This is the total line that is send: #S,SENDK,[pId; sensorValue {TAB} potValue2 {DOWN} {LEFT} ]#
     Serial.print("#S|SENDK|[");
     Serial.print(itoa((pId), buffer, 10));
     Serial.print("&");
     Serial.print(itoa((sensorValue), buffer, 10));
     Serial.print(" {ENTER} ");
     Serial.println("]#");
     // wait up to 1000 ms for answer from Gobetwino, answer will be in serInString, answer is 0 if all is OK
     readSerialString(serInString, 1000);
     //Deal with answer here - omitted in this example
     delay(10);
  }    
} 

//read a string from the serial and store it in an array
//you must supply the array variable - will return if timeOut ms passes before the sting is read so you should
//check the contents of the char array before making any assumptions.
void readSerialString (char *strArray,long timeOut) 
{
   long startTime=millis();
   int i;

   while (!Serial.available()) {
      if (millis()-startTime >= timeOut) {
         return;
      }
   }
   while (Serial.available() && i < serInLen) {
      strArray[i] = Serial.read();
      i++;
   }
}

Enjoy! Any questions, send me a PM