For week 2 I continued to test the hardware I have on hand and then try to interface everything via code and hardwiring.Im glad to say that I am about 75% of the way done with the selected parts. I had some problems with the CHR-6dm sensor and reinitializing it so it has been sent back to manufacturer for reprogramming. Seems like the problem was on my end with a faulty usb - serial adapter. So while I wait for the unit to come back to me I have a Sparkfun 5DOF board to play with and try to convert accelerometer data to angular pitch roll data. After A LOT of reading and searching I have found code that does exactly what I need. I'm confident I could have figured it out but it would have taken months to get to a point where I would be confident with the numbers I am getting. I would like to thank the Arduino forum for this because without it I would be lost. the code can be found at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1286541868 for anyone looking or interested.
My next problem is to take the code for polling GPS data and combine it with the accelerometer code to get 2 solid strings output to my Logomatic Datalogger. The code for the GPS searches for a GPRMC string and then parses the data out to the serial line. The problem I am having is that for every character parsed the accelerometer data is posted so I end up with nonsense data for gps and current pitch roll data. If I insert the pitch roll code into the GPS parser then I end up with current GPS data and lagging pitch roll data because I am only interested in acquiring data every 1s and not continuous. Here is my code to date.... Feel free to read over and tear apart.
#include <string.h>
#include <ctype.h>
#include <math.h>
#define xAcc 0
#define yAcc 1
#define zAcc 2
#define xGyro 4
#define yGyro 5
#define vRef 3.3
#define sen 0.330
#define gSen 0.002
#define gyroZero 1.350
int x0,y0,z1,gx0,gy0,gz0; //x0,y0,z0 is x,y,z axis zero G ADC value gx0,gy0 no rotation ADC values
float xAngle,yAngle,xAtan,yAtan,zAngle,dxAngle,dyAngle =0;
unsigned long time,dt = 0;
int ledPin = 13; // LED test pin
int rxPin = 0; // RX PIN
int txPin = 1; // TX TX
int byteGPS=-1;
char linea[300] = "";
char comandoGPR[7] = "$GPRMC";
int count=0;
int counta=0;
int countb=0;
int index[13];
const int xpin = A0; // x-axis of the accelerometer
const int ypin = A1; // y-axis
const int zpin = A2; // z-axis (only on 3-axis models)
const int xRate = A4;
const int yRate = A5;
void setup() {
pinMode(ledPin, OUTPUT); // Initialize LED pin
pinMode(rxPin, INPUT);
pinMode(txPin, OUTPUT);
Serial.begin(38400);
delay(1000);
getZeros();
for (int i=0;i<300;i++){ // Initialize a buffer for received data
linea[i]=' ';
}
}
void getZeros()
{
x0=analogRead(xAcc);
y0=analogRead(yAcc);
z1=analogRead(zAcc);
gx0=analogRead(xGyro);
gy0=analogRead(yGyro);
}
void loop() {
digitalWrite(ledPin, HIGH);
byteGPS=Serial.read(); // Read a byte of the serial port
if (byteGPS == -1) { // See if the port is empty yet
delay(1000);
} else {
linea[counta]=byteGPS; // If there is serial port data, it is put in the buffer
counta++;
Serial.print(byteGPS, BYTE);
if (byteGPS==13){ // If the received byte is = to 13, end of transmission
digitalWrite(ledPin, LOW);
count=0;
countb=0;
for (int i=1;i<7;i++){ // Verifies if the received command starts with $GPR
if (linea[i]==comandoGPR[i-1]){
countb++;
}
}
if(countb==6){ // If yes, continue and process the data
for (int i=0;i<300;i++){
if (linea[i]==','){ // check for the position of the "," separator
index[count]=i;
count++;
}
if (linea[i]=='*'){ // ... and the "*"
index[12]=i;
count++;
}
}
Serial.println("");
Serial.print("$CTAH,");
Serial.print("xpin,");
Serial.print(analogRead(xpin));
Serial.print(",");
Serial.print("ypin,");
Serial.print(analogRead(ypin));
Serial.print(",");
Serial.print("zpin,");
Serial.print(analogRead(zpin));
Serial.print(",");
Serial.print(analogRead(xRate), DEC);
Serial.print(",");
Serial.print(analogRead(yRate), DEC);
Serial.println();
Serial.print("Roll");
Serial.print("\t");
Serial.print("Pitch");
Serial.println();
GetPR();
}
counta=0; // Reset the buffer
for (int i=0;i<300;i++){ //
linea[i]=' ';
}
}
}
}
void GetPR()
{
//******************** CF filter******************************************************************
time=millis();
xAtan=atan2((analogRead(xAcc)-x0)*vRef/(1024*sen),(analogRead(zAcc)-z1)*vRef/(1024*sen)+1)*180/PI;
yAtan=atan2((analogRead(yAcc)-y0)*vRef/(1024*sen),(analogRead(zAcc)-z1)*vRef/(1024*sen)+1)*180/PI;
dxAngle=(analogRead(yGyro)-gy0)*vRef/(1024*gSen);
dyAngle=(analogRead(xGyro)-gx0)*vRef/(1024*gSen);
xAngle = 0.9615 * (xAngle + dxAngle*dt*0.001) + 0.0385*xAtan;
yAngle =0.9615 * (yAngle + dyAngle*dt*0.001) + (0.0385 *yAtan);
//0.9615 is a and its given by a=tau/(tau-dt), 0.0385=1-a
// dt is 1-2 ms
//************************************************************************************************
Serial.print(xAngle);
Serial.print("\t");
Serial.print(yAngle);
Serial.print("\t");
Serial.println(dt);
dt=millis()-time;
}
