geophysical logger code for Ardunio Uno

geophysical_logger.ino

#include <AltSoftSerial.h>
/* 
Arduino geophysical logger

v1 2016-09-30 17:00

Arduino hardware setup:

Pin 8 - wire to RS232 Shield RXD pin on left side
Pin 9 - wire to RS232 Shield TXD pin on left side

Pin 2 - ENC A
Pin 3 - ENC B

At high speed it seems to miss counts, and interpret them as coming in the wrong direction i.e. out of phase.

Columns output to computer (115200 baud RS232 over Arduino USB cable)

- depth encoder pulse counting enabled (1=on, 0=off)
- current pulses per metre setting (PPM)
- current depth
- current absolute depth encoder pulse position
- change in encoder pulses per interval
- time since arduino started in microseconds
- time since last interval
- speed in encoder pulses per second, showing direction
- speed in metres per minute, showing direction
- data line received from probe, if end of line has been reached

Command lines that can be sent to arduino via USB:

dN# - set depth, N is any number including decimal point or negative sign e.g. -0.5 or 3.21
      note that it will set the encoder pulse position to zero.
pN# - set pulses per metre setting (PPM), n any floating point number as above.
c#  - start/stop reading encoder pulses
i#  - flip the direction in which the encoder is reading. This DOES NOT
      affect the absolute encoder pulse position, only the converted
      depth

*/

// fix bizarre arduino linker bug on XP:
int aa;
int bb;
int cc;
int dd;
int ee;
int ff;
int gg;
int hh;
int ii;
int jj;
int kk;
// end fix

// Pin definitions.
// - enc_a is ENC Signal A line (Arduino digital pin 2)
// - enc_b is ENC Signal B line (Arduino digital pin 3)
#define ENC_A  2
#define ENC_B  3

// Main loop refresh period.
#define REFRESH_MS  180

// Main serial data connection to computer.
#define BAUD_RATE   115200

// RS-232 connection (receive only)
#define RS232_BAUD_RATE     2400

// Encoder position
int enc_count = 1;     // either 1 (count pulses) or 0 (ignore pulses)
int enc_polarity = 1;  // either 1 or -1 (flip the direction)
volatile long enc_pos = 0; 
int enc_pos_prev = 0;
int enc_pos_change = 0;

// Speed
float sec_change;

// Encoder calibration
float ppm = 1000;
float depth = 0;
float depth_change;

// Timing
unsigned long micros_current = 0;
unsigned long micros_prev = 0;
long micros_change = 0;

// RS-232 data buffer
int RS232_buffer[50];
int c = 0;
int i = 0;
int j = 0;

// Computer to Arduino communication buffer
String computer_buffer;

AltSoftSerial serial_RS232;

void setup() 
{
    pinMode(ENC_A, INPUT);
    pinMode(ENC_B, INPUT); 

    attachInterrupt(0, interrupt_enc_a, RISING);
  
    micros_prev = micros();

    Serial.begin(BAUD_RATE);
    serial_RS232.begin(RS232_BAUD_RATE);
}


void loop()
{
    // Calculate elapsed time  
    micros_current = micros();
    if (micros_current < micros_prev) {
        micros_change = micros_current + (4294967295 - micros_prev);
    } else {
        micros_change = micros_current - micros_prev;
    }

    // Calculate change in encoder position.
    enc_pos_change = (enc_pos - enc_pos_prev);// * enc_polarity * enc_count;
    depth_change = enc_pos_change / ppm * enc_polarity;
    depth += depth_change;
    sec_change = micros_change / 1000000.;

    // Read data from RS-232 buffer
    while (serial_RS232.available()) {
        c = serial_RS232.read();
        if (c == 13) {         // the other line break character...
            continue;
        } else if (c == 10) {  // line break
            break;
        } else {
            RS232_buffer[j] = c;
            if (j < 50) j++;
        } 
    }

    // Check for transmission from the computer.
    while (Serial.available()) {
        char c2 = Serial.read();
        computer_buffer += c2;
    }

    // Check to see if we have a complete communication from the computer.
    computer_buffer.trim();
    int n = computer_buffer.length();
    if (computer_buffer[n - 1] == '#') {         // all commands must end with #
        if (computer_buffer[0] == 'p') {          // Reset PPM value.
            computer_buffer.remove(0, 1);
            computer_buffer.remove(n - 1);
            ppm = computer_buffer.toFloat();
        } else if (computer_buffer[0] == 'd') {    // set depth
            computer_buffer.remove(0, 1);
            computer_buffer.remove(n - 1);
            depth = computer_buffer.toFloat();
            enc_pos = 0;
        } else if (computer_buffer[0] == 'c') {   // Start or stop counting encoder pulses.
            enc_count = !enc_count;
        } else if (computer_buffer[0] == 'i') {   // flip encoder polarity.
            if (enc_polarity > 0) {
                enc_polarity = -1;
            } else {
                enc_polarity = 1;
            }
        }
        computer_buffer = "";
    }
    
    // Send encoder information to computer.
    Serial.print(enc_count);
    Serial.print("\t");
    Serial.print(ppm);
    Serial.print("\t");
    Serial.print(depth);
    Serial.print("\t");
    Serial.print(enc_pos);
    Serial.print("\t");
    Serial.print(enc_pos_change);
    Serial.print("\t");
    Serial.print(micros_current);
    Serial.print("\t");
    Serial.print(micros_change);
    Serial.print("\t");
    Serial.print(enc_pos_change / sec_change);
    Serial.print("\t");
    Serial.print(depth_change / sec_change);
    Serial.print("\t");

    // Relay the serial data to the computer, if the buffer is full.
    if (c == 10) {
        for (i = 0; i < j; i++) {
            Serial.write(RS232_buffer[i]);
        }
        j = 0;
    }

    // End of transmission to computer.
    Serial.print("\n");

    // Wait for a specified period (REFRESH_MS).
    enc_pos_prev = enc_pos;
    micros_prev = micros_current;
    
    delay(REFRESH_MS);
}

// Detect pulses from depth encoder.

void interrupt_enc_a()
{
    if (enc_count) {
        if (boolean) digitalRead(ENC_B) {
              enc_pos++;
        } else {
              enc_pos--;
        }
    }
}

output.txt

1	1000.00	-0.00	-3	0	57668420	182404	0.00	0.00	00128 22222 44444 33333
1	1000.00	-0.00	-3	0	57850964	182544	0.00	0.00	00116 22222 44444 33333
1	1000.00	-0.00	-3	0	58033568	182604	0.00	0.00	00091 22222 44444 33333
1	1000.00	-0.00	-3	0	58216168	182600	0.00	0.00	
1	1000.00	-0.00	-3	0	58398584	182416	0.00	0.00	00189 22222 44444 33333
1	1000.00	-0.00	-3	0	58581128	182544	0.00	0.00	00159 22222 44444 33333
1	1000.00	-0.00	-3	0	58763728	182600	0.00	0.00	00221 22222 44444 33333
1	1000.00	-0.00	-3	0	58946332	182604	0.00	0.00	
1	1000.00	-0.00	-3	0	59128724	182392	0.00	0.00	00228 22222 44444 33333
1	1000.00	-0.00	-3	0	59311284	182560	0.00	0.00	00293 22222 44444 33333
1	1000.00	-0.00	-3	0	59493896	182612	0.00	0.00	
1	1000.00	-0.00	-3	0	59676336	182440	0.00	0.00	00436 22222 44444 33333
1	1000.00	-0.00	-3	0	59858848	182512	0.00	0.00	00761 22222 44444 33333
1	1000.00	-0.00	-3	0	60041460	182612	0.00	0.00	01080 22222 44444 33333
1	1000.00	-0.00	-3	0	60224068	182608	0.00	0.00	
1	1000.00	-0.00	-3	0	60406508	182440	0.00	0.00	01372 22222 44444 33333
1	1000.00	-0.00	-3	0	60589024	182516	0.00	0.00	01718 22222 44444 33333
1	1000.00	-0.00	-3	0	60771636	182612	0.00	0.00	01832 22222 44444 33333
1	1000.00	-0.00	-3	0	60954244	182608	0.00	0.00	
1	1000.00	-0.00	-3	0	61136712	182468	0.00	0.00	02052 22222 44444 33333
1	1000.00	-0.00	-3	0	61319248	182536	0.00	0.00	01956 22222 44444 33333
1	1000.00	-0.00	-3	0	61501856	182608	0.00	0.00	01948 22222 44444 33333
1	1000.00	-0.00	-3	0	61684456	182600	0.00	0.00	
1	1000.00	-0.00	-3	0	61866924	182468	0.00	0.00	01639 22222 44444 33333
1	1000.00	-0.00	-3	0	62049464	182540	0.00	0.00	01475 22222 44444 33333
1	1000.00	-0.00	-3	0	62232064	182600	0.00	0.00	00908 22222 44444 33333
1	1000.00	-0.00	-3	0	62414676	182612	0.00	0.00	
1	1000.00	-0.00	-3	0	62597136	182460	0.00	0.00	00551 22222 44444 33333
1	1000.00	-0.00	-3	0	62779672	182536	0.00	0.00	00387 22222 44444 33333
1	1000.00	-0.00	-3	0	62962276	182604	0.00	0.00	00267 22222 44444 33333
1	1000.00	-0.00	-3	0	63144888	182612	0.00	0.00	
1	1000.00	-0.00	-3	0	63327340	182452	0.00	0.00	00143 22222 44444 33333
1	1000.00	-0.00	-3	0	63509868	182528	0.00	0.00	00105 22222 44444 33333
1	1000.00	-0.00	-3	0	63692472	182604	0.00	0.00	00078 22222 44444 33333
1	1000.00	-0.00	-3	0	63875084	182612	0.00	0.00	
1	1000.00	-0.00	-3	0	64057524	182440	0.00	0.00	00093 22222 44444 33333
1	1000.00	-0.00	-3	0	64240060	182536	0.00	0.00	00094 22222 44444 33333
1	1000.00	-0.00	-3	0	64422668	182608	0.00	0.00	00064 22222 44444 33333
1	1000.00	-0.00	-3	0	64605276	182608	0.00	0.00	
1	1000.00	-0.00	-3	0	64787700	182424	0.00	0.00	00077 22222 44444 33333
1	1000.00	-0.00	-3	0	64970236	182536	0.00	0.00	00085 22222 44444 33333
1	1000.00	-0.00	-3	0	65152848	182612	0.00	0.00	00116 22222 44444 33333
1	1000.00	-0.00	-3	0	65335460	182612	0.00	0.00	
1	1000.00	-0.00	-3	0	65517872	182412	0.00	0.00	00119 22222 44444 33333
1	1000.00	-0.00	-3	0	65700404	182532	0.00	0.00	00086 22222 44444 33333
1	1000.00	-0.00	-3	0	65883016	182612	0.00	0.00	00100 22222 44444 33333
1	1000.00	-0.00	-3	0	66065628	182612	0.00	0.00