[Flightcomputer] HoHoHo III

Summary

This is the flightcomputer for the infamous HoHoHo III.

It uses GPS serial data from a GPS receiver, strips it and parses it to a NTX2 433mhz radio transmitter. Also, it fires of a Canon EOS350 which makes nice pictures. Furthermore, it rotates a servo as release mechanism when it crosses certain borders.

Also, it sends a textmessage through a Sony Ericsson with serial interface (in this case a t68i) to send a textmessage when it lands.

Parts List

  • NTX2 Radio transmitter
  • GPS receiver with serial interface
  • Arduino or equivalent
  • Sony Ericsson with serial (old) interface

Code

excuse the messy layout, but thats WordPress’s fault (and my lazynesses’)


// Project Hollands Hoogte © July 2010
// By Tim Zaman
// Help from Terry Baume (& ntx2 by jharrison)

// Digital Pins
#define GPS_PIN_RX 9 // GPS serial pin RX
#define GPS_PIN_TX 8 // GPS serial pin TX
#define RTTY_PIN_1 2 // RTTY space pin
#define RTTY_PIN_2 3 // RTTY mark pin
#define GSM_PIN_RX 5 // GPS serial pin RX
#define GSM_PIN_TX 4 // GPS serial pin TX
#define PHOTOPIN 7 // Photopin to EOS350D
#define RELEASEPIN 6 // Releasepin to Arduino Duemilenova

// Baudot
#define ARRAY_LEN 32
#define LETTERS_SHIFT 31
#define FIGURES_SHIFT 27
#define LINEFEED 2
#define CARRRTN 8

#define is_lowercase(ch) ((ch) >= 'a' && (ch) = 'A' && (ch) <= 'Z')

// T68i
#define num_to_char(number) ((number) > 4)
#define hexdump_a(byte) num_to_char( last_four(byte))
#define hexdump_b(byte) num_to_char(first_four(byte))

// Misc
#define RTTY_ASCII 7 // ASCII set for RTTY (7/8bit)
#define GPSRATE 9600 // GPS baud rate
#define BUFFERSIZE 90 // How many bytes of input to buffer from the GPS?
#define ENDLN "\r\n" // SD

#include
#include
#include
#include
//#include

#include

//baudot
char letters_arr[33] = "00E\nA SIU\rDRJNFCKTZLWHYPQOBG00MXV00";
char figures_arr[33] = "003\n- \a87\r$4',!:(5\")2#6019?&00./;00";

// Initialize flight variables
int numSats = 0;
int fixType = 0;
int time[] = {
0, 0, 0};
double latitude = 0.0;
double longitude = 0.0;
long altitude = 0;
long maxAlt = 0;
int speed = 0;
int txCount = 0;
int intTemp = 0;
int extTemp = 0;
int intHum = 0;
int bitRate = 50;
int descent = 0;
double lon_release = 5.59;
double lon_test = 4.6996;

unsigned long SmsStart = 0; // SMS-time
unsigned long GpsAltTime = 1800000; // 1.800.000ms=1.800s=30min
int ExecOnce=0; // execut0r
int ExecOneRelease=0; // voor 24km limit ding
char buffer[BUFFERSIZE];
byte nxtln[] = ENDLN; //SD ENDLNn
unsigned long NXTlength = sizeof(ENDLN)-1; //SD ENDLNn length

SoftwareSerial GPS = SoftwareSerial(GPS_PIN_RX, GPS_PIN_TX); //(rx,tx)
SoftwareSerial GSM = SoftwareSerial(GSM_PIN_RX, GSM_PIN_TX); //(rx,tx)

void setup() {

// Start up serial ports

Serial.begin(9600);
Serial.println("Serial started");
GPS.begin(4800);
GSM.begin(9600);

// LED's
delay(1000);
GPS.println("$PSTMNMEACONFIG,0,4800,1,1");
GPS.println("$PSTMINITGPS,5200.000,N,00421.000,E,0197,22,10,2007,11,40,00");
GPS.println("$PSRF103,02,00,00,01*26");

// Canon EOS 350D
pinMode(PHOTOPIN,OUTPUT);
pinMode(RELEASEPIN,OUTPUT);
// Setup for RTTY
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);

//GPS
pinMode(GPS_PIN_RX, INPUT);
pinMode(GPS_PIN_TX, OUTPUT);

//GSM
pinMode(GSM_PIN_RX, INPUT);
pinMode(GSM_PIN_TX, OUTPUT);

}

void loop() {

// Get a GGA string from the GPS,
// check if it's a valid fix, and extract the data
getNMEA("$GPGGA");
numSats = getSats();
fixType = getFixType();

digitalWrite(RELEASEPIN, LOW);

// Make sure we have a valid fix
if (fixType != 0) {
getTime(time);
latitude = getLat();
longitude = getLong();
altitude = getAlt();

// Keep track of the maximum altitude
if (altitude > maxAlt) {
maxAlt = altitude;
}

// Check to see if we've fallen 600m, if so switch to descent mode
if (altitude 100){ //En we zeker 100 strings hebben gehad
if (longitude > lon_release){ //En hij is rond flevoland
ExecOneRelease = 1;
digitalWrite(RELEASEPIN, HIGH);
TxString("RELEASE MECHANISM IN OPERATION");
delay(100);
}
}
}

if(txCount == 10){
send_sms(buffer);
delay(50);
}

if (txCount >12){ //Na 12 strings
if ( (txCount & 0x01) == 0) { //Elke oneven
digitalWrite(PHOTOPIN, HIGH); //Maak foto
Serial.println("Foto");
}
}

if (altitude > 23000){
if (ExecOneRelease == 0){
ExecOneRelease = 1;
digitalWrite(RELEASEPIN, HIGH);
}
}

// Transmit and log to SD card
TxString(buffer);

digitalWrite(PHOTOPIN, LOW); //Put low anyway

// SMS <1000m mode
if (descent == 1){
if (altitude 25000){
ExecOnce =0;
}

}
}

// Delay a moment before restarting loop
delay(100);

} //end

// ------- GPS Parsing ----------

// Reads a line from the GPS NMEA serial output
// Give up after trying to read 1000 bytes (~2 seconds)
int readLine(void) {
char c;
byte bufferIndex = 0;
boolean startLine = 0;
byte retries = 0;
while (retries 0) {

c= GPS.read();

if (c == -1) {
delay(2);
continue;
}
if (c == '\n') continue;
if (c == '$') startLine = 1;
if ((bufferIndex == BUFFERSIZE-1) || (c == '\r')) {
if (startLine) {
buffer[bufferIndex] = 0;
return 1;
}
}
if (startLine) buffer[bufferIndex++] = c;
//}
else {
retries++;
delay(50);
}
}
Serial.println(buffer);
return 0;
}

// Returns a specific field from the buffer
void getField(int getId, char *field, int maxLen) {
byte bufferIndex = 0;
byte fieldId = 0;
byte i = 0;
while (bufferIndex (maxLen - 2)) {
field[i] = 0; // Null terminate
return;
}
// Buffer chars to field
field[i++] = buffer[bufferIndex++];
}
else {
// Advance field on comma
if (buffer[bufferIndex] == ',') {
bufferIndex++; // Advance in buffer
fieldId++; // Increase field position counter
}
else {
bufferIndex++; // Advance in buffer
}
}
}
// Null terminate incase we didn't already..
field[i] = 0;
}

// Polls for an NMEA sentence of type requested
// Validates checksum, silently retries on failed checksums
int getNMEA(char *getType) {
char type[7];
byte retries = 0;
while (retries < 2) {
if (readLine() && validateChecksum()) {
;
getField(0, type, sizeof(type));
if (strcmp(type, getType) == 0) {
Serial.println(buffer);
return 1;
}
}
else {
retries++;
}
}
Serial.println("Failed to read GPS");
return 0;
}

// Validates the checksum on an NMEA string
// Returns 1 on valid checksum, 0 otherwise
int validateChecksum(void) {
char gotSum[2];
gotSum[0] = buffer[strlen(buffer) - 2];
gotSum[1] = buffer[strlen(buffer) - 1];
// Check that the checksums match up
if ((16 * atoh(gotSum[0])) + atoh(gotSum[1]) == getCheckSum(buffer)) return 1;
else return 0;
}

// Calculates the checksum for a given string
// returns as integer
int getCheckSum(char *string) {
int i;
int XOR;
int c;
// Calculate checksum ignoring any $'s in the string
for (XOR = 0, i = 0; i < strlen(string); i++) {
c = (unsigned char)string[i];
if (c == '*') break;
if (c != '$') XOR ^= c;
}
return XOR;
}

// Returns the groundspeed in km/h
int getSpeed(void) {
char field[10];
getField(7, field, sizeof(field));
int speed = atoi(field);
return speed;
}

// Return the fix type from a GGA string
int getFixType(void) {
char field[5];
getField(6, field, sizeof(field));
int fixType = atoi(field);
return fixType;
}

// Return the altitude in meters from a GGA string
long getAlt(void) {
char field[10];
getField(9, field, sizeof(field));
long altitude = atol(field);
return altitude;
}

// Returns the number of satellites being tracked from a GGA string
int getSats(void) {
char field[3];
getField(7, field, sizeof(field));
int numSats = atoi(field);
return numSats;
}

// Read the latitude in decimal format from a GGA string
double getLat(void) {
char field[12];
getField(2, field, sizeof(field)); // read the latitude
double latitude = atof(field); // convert to a double (precise)
int deg = (int) latitude / 100; // extract the number of degrees
double min = latitude - (100 * deg); // work out the number of minutes
latitude = deg + (double) min/60.0; // convert to decimal format
getField(3, field, sizeof(field)); // get the hemisphere (N/S)
if (strcmp(field, "S") == 0) latitude *= -1; // sign the decimal latitude correctly
return latitude;
}

// Read the longitude in decimal format from a GGA string
double getLong(void) {
char field[12];
getField(4, field, sizeof(field)); // read the longitude
double longitude = atof(field); // convert to a double
int deg = (int) longitude / 100; // extract the number of degrees
double min = longitude - (100 * deg); // work out the number of minutes
longitude = deg + (double) min/60.00; // convert to decimal format
getField(5, field, sizeof(field)); // get the E/W status
if (strcmp(field, "W") == 0) longitude *= -1; // sign decimal latitude correctly
return longitude;
}

// Converts UTC time to the correct timezone
void convertTime(int *time) {
// How many hours off GMT are we?
float offset = 1;
long sectime = ((long)(time[0]) * 3600) + (time[1] * 60) + time[2];
sectime += (offset * 3600.0);
// Did we wrap around?
if (sectime 86400) sectime -= 86400;
// Convert back to time
time[0] = (int)(sectime / 3600);
time[1] = (int)((sectime % 3600) / 60);
time[2] = (int)((sectime % 3600) % 60);
}

// Parses a time field from a GGA string
void parseTime(char *field, int *time) {
char tmp[3];
tmp[2] = 0; // Init tmp and null terminate
tmp[0] = field[0];
tmp[1] = field[1];
time[0] = atoi(tmp); // Hours
tmp[0] = field[2];
tmp[1] = field[3];
time[1] = atoi(tmp); // Minutes
tmp[0] = field[4];
tmp[1] = field[5];
time[2] = atoi(tmp); // Seconds
}

// Gets the hours, minutes and seconds from a GGA string
void getTime(int *time) {
char field[12];
getField(1, field, sizeof(field));
parseTime(field, time);
convertTime(time);
}

// ------ RTTY ----------

// Transmit a string, log it to SD & produce debug output
void TxString(char *string) {
// Checksum
char txSum[4];
int checkSum = getCheckSum(string);
sprintf(txSum, "%02X", checkSum);
Serial << F("RTTY: ") << string << "#" << txSum << ENDLN;
rtty_txstring(string);
rtty_txstring("#");
rtty_txstring(txSum);
rtty_txstring("\r\n");
}

uint8_t char_to_baudot(char c, char *array)
{
int i;
for (i = 0; i = 0; i--) */
for (i = 0; i < 5; i++)
{
if (b & (1 < Richman

void hexdump_byte(unsigned char byte)
{
GSM.print(hexdump_a(byte), BYTE);
GSM.print(hexdump_b(byte), BYTE);
}

void send_sms(char *data)
{
size_t data_length, x;
char c, l;
long i;
long n;

data_length = strlen(data);
i = data_length * 7;

/* Round i up to a multiple of 8 */
if (i & 0x07) i = (i & ~0x07) + 0x08;

/* Calculate the number of message octets */
i = i / 8;

GSM.println("AT+CMGF=0");
delay(1500);
GSM.print("AT+CMGS=");
delay(1500);
GSM.println(i + 14);
delay(1500);
GSM.print("0011000B911356537837F80000AA");
hexdump_byte(data_length & 0xFF);

/* from sms_example_v2.c ALIEN Project Daniel Richman */
l = 0;
n = 0;

for (x = 0; x < data_length; x++)
{
if (data[x] == '$') data[x] = 0x02;

n |= (data[x] & 0x7F) <= 8)
{
hexdump_byte(n & 0xFF);
l -= 8;
n >>= 8;
}
}

if (l != 0)
{
hexdump_byte(n & 0xFF);
}

GSM.println(0x1A, BYTE);
}

// DO NOT COPYRIGHT WITHOUT HIS PERMISSION
// ------ MISC ----------

// Returns a string with a textual representation of a float
void doubleToString(double val, int precision, char *string){

// Print the int part
sprintf(string, "%d", (int)(val));
if(precision > 0) {
// Print the decimal point
strcat(string, ".");
unsigned long frac;
unsigned long mult = 1;
int padding = precision -1;
while (precision--) {
mult *=10;
}
if (val >= 0)
frac = (val - (int)(val)) * mult;
else
frac = ((int)(val)- val ) * mult;
unsigned long frac1 = frac;
while (frac1 /= 10) {
padding--;
}
while (padding--) {
strcat(string, "0");
}

// Convert and print the fraction part
sprintf(string+strlen(string), "%d", (int)(frac));
}
}

// Converts a HEX string to an int
int atoh(char c) {
if (c >= 'A' && c = 'a' && c <= 'f')
return c - 87;
else
return c - 48;
}

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