I thought I would post my HAB Arduino Data Logger code here so all could benefit. It is pretty straightforward and also covered at length on my YouTube videos. The data logger would work great for any other applications too- not just weather balloons.
Here is the Arduino Code. Enjoy!
/*
My Youtube Channel : http://www.youtube.com/user/Shadow5549
Complete build source code related files can be found here: http://www.thingiverse.com/thing:252267
This is SD card datalogger designed to supportthe High Altitude Ballon Project which can be followed on my YouTube videos
Videos will be produced throughout the development of this project. Each stage will be
doccumented seprately and shared in order (hopefully)
From Arduino Example Code:
This example shows how to log data from analog sensors to an SD card using the SD library.
The circuit:
* analog sensors on analog ins 0, 1,
* SD card attached to SPI bus as follows:
** MOSI - pin 11
** MISO - pin 12
** CLK - pin 13
** CS - pin 4 (digital assigned via setup)
** VCC & Ground
-------------------------------------------------------------------
V2-
Adding RTC support
RTC Connected to VCC and Ground
I2C Connections:
RTC SDA connected to pin Analog 4
RTC SCL connected to pin Analog 5
Used I2CScanner.ino to find I2C addresses- 0x50 (EEPROM?) and 0x68 found
Used SetRTC.ino to manually set proper date/date on RTC module- This wil set the date/time as soon as serial
is initiated so set ahead by a minute and wait till time matches then open serial window to set.
-----------------------------------------------------------------------
V3-
Added Adafruit 992- MPL115A2 Baro/Temp Sensor 5volt 12C device
SDA connected to pin Analog 4
SCL connected to pin Analog 5
Code below should be optimized to avoid multiple I2C calls
Added Battery Voltage Monitoring:
Changed A0 to be used for Bus Voltage monitoring (on board LiPo)
Will use voltage divider with 2 10Kohm resistores to monitor the 7.4V supply from battery
http://forum.arduino.cc/index.php/topic,13728.0.html
Testing- Ran solid 15 hours no issues, 47000 lines recorded, Filesize 2.1MB
-----------------------------------------------------------------------
V4
Added output for altitude in meters (Thanks Jon)
http://forum.arduino.cc/index.php?topic=63726.0
Used static value of 15 for Temp as using actual temp causes unreliable values indoors
------------------------------------------------------------------------
V5
Added code for LM35 Temp sensor (Will be internal monitoring) on A1 data2 and temp variables
Had to do 2 analog reads to debounce the values with a small delay.
Added Bluetooth- shortened serial write text to fit phone screen
W
----------------------------------------------------------------------
*/
#include <Adafruit_MPL115A2.h>// Support for Baro Sensor Adafruit 992- MPL115A2
Adafruit_MPL115A2 mpl115a2;//Support for Baro Sensor Adafruit 992- MPL115A2
#include "Wire.h"
#define DS1307_ADDRESS 0x68//RTC Support
//Eric Note- another address showed up in scan at 0X50 EEPROM?
byte zero = 0x00; //workaround for issue #527 RTC Support
const float referenceVolts = 5.0; // the default reference on a 5 volt board
const int batteryPin = 0; // +V from battery is connected to analog pin 0
const float sea_press = 1013.25;//added for altitude calc
float alt=0;//added for altitude calc
#include <SD.h>
File myFile; //SD
const int chipSelect=4; // set chipselect pin to 4 for SD
//int dat1=A0;//set data pin
int dat2=1;//define pin0 connect with LM35
float temp=0;
//int data1=0;
int data2=0;
int i=0;
boolean present=0;// SD Card available & usable
void setup()
{
Wire.begin();
Serial.begin(9600);
mpl115a2.begin();// Baro Sensor Adafruit 992- MPL115A2
//pinMode(dat1,INPUT);
pinMode(dat2,INPUT);
checkSD();
// Write column headers for Excel CSV
myFile = SD.open("datalog.csv", FILE_WRITE);
if(myFile)
{
//Prints headers to file
myFile.print("Time"); // Prints Date and Time header
myFile.print(",");
myFile.print("line#");// prints line number Header for troubleshooting etc
myFile.print(",");
myFile.print("BusVoltage");
myFile.print(",");
myFile.print("IntTemp");
myFile.print(",");
myFile.print("Pressure");
myFile.print(",");
myFile.print("ExtTemp");
myFile.print(",");
myFile.println("Alt(m)");
myFile.close();
}
}
void loop()
{
int val = analogRead(batteryPin); // read the value from the A0 battery monitoring pin with voltage divider
float volts = (val / 511.0) * referenceVolts ; // divide val by (1023/2)because the resistors divide the voltage in half
float pressureKPA = 0, temperatureC = 0; //Adafruit 992- MPL115A2
if(present==1)
{
pressureKPA = mpl115a2.getPressure();//get pressure Adafruit 992- MPL115A2
temperatureC = mpl115a2.getTemperature(); //Adafruit 992- MPL115A2
printDate(); //Runs the print date subroutine below
i++;
//data1=analogRead(dat1);
analogRead(1);// added to take initial read to stabilize the ADC
delay(10);// Delay to stabilize the ADC
temp = analogRead(1) * 5000L / 1024L / 10;// Temperature calculation formula
//data2=analogRead(dat2); //used for Ext Temp sensor TBD
//temp= data2 * 4.9 / 10 ; // Temperature calculation formula
Serial.print(" BusV:");
Serial.print(volts);
Serial.print(" ITemp:");
Serial.print(temp);
Serial.print(" Press:");
Serial.print(pressureKPA, 4);
Serial.print(" ExTemp:");
Serial.print(temperatureC, 1);
alt= ((pow((sea_press / (pressureKPA *10)), 1/5.257) - 1.0) * (15 + 273.15)) / 0.0065;//rough altitude equation in meters can use real temp instead of 15
Serial.print(" Alt:");
Serial.println(alt);
writeSD();
}
delay(1000);
}
byte decToBcd(byte val){ //Eric- needed for RTC variable stuff
// Convert normal decimal numbers to binary coded decimal
return ( (val/10*16) + (val%10) );
}
byte bcdToDec(byte val) { //Eric- needed for RTC variable stuff
// Convert binary coded decimal to normal decimal numbers
return ( (val/16*10) + (val%16) );
}
void checkSD()
{
Serial.print("check SD card");
if (!SD.begin(chipSelect)) {
Serial.println("Card failed");
// don't do anything more:
return;
}
Serial.println("SD card OK");
present=1;
delay(2000);
}
void writeSD()
{
myFile = SD.open("datalog.csv", FILE_WRITE);
if(myFile)
{
int val = analogRead(batteryPin); // read the value from the A0 battery monitoring pin with voltage divider
float volts = (val / 511.0) * referenceVolts ; // divide val by (1023/2)because the resistors divide the voltage in half
// Reset the register pointer
Wire.beginTransmission(DS1307_ADDRESS);
Wire.write(zero);
Wire.endTransmission();
Wire.requestFrom(DS1307_ADDRESS, 7);
int second = bcdToDec(Wire.read());
int minute = bcdToDec(Wire.read());
int hour = bcdToDec(Wire.read() & 0b111111); //24 hour time
int weekDay = bcdToDec(Wire.read()); //0-6 -> sunday - Saturday
int monthDay = bcdToDec(Wire.read());
int month = bcdToDec(Wire.read());
int year = bcdToDec(Wire.read());
float pressureKPA = mpl115a2.getPressure();//get pressure Adafruit 992- MPL115A2- these are redundant calls to I2c but I dont want to fix
float temperatureC = mpl115a2.getTemperature();//get temp Adafruit 992- MPL115A2- these are redundant calls to I2c but I dont want to fix
//Print RTC values to SD
myFile.print(month);
myFile.print("/");
myFile.print(monthDay);
myFile.print("/");
myFile.print(year);
myFile.print(" ");
myFile.print(hour);
myFile.print(":");
myFile.print(minute);
myFile.print(":");
myFile.print(second);
//myFile.print(":");
myFile.print(",");
//End Print RTC values
myFile.print(i);
myFile.print(",");
myFile.print(volts);
myFile.print(",");
myFile.print(temp);
myFile.print(",");
myFile.print(pressureKPA, 4);
myFile.print(",");
myFile.print(temperatureC, 1);
myFile.print(",");
myFile.println(alt);
myFile.close();
}
}
void printDate()// Only used to print to serial and not needed for logging purposes
{
Wire.beginTransmission(DS1307_ADDRESS);
Wire.write(zero);
Wire.endTransmission();
Wire.requestFrom(DS1307_ADDRESS, 7);
int second = bcdToDec(Wire.read());
int minute = bcdToDec(Wire.read());
int hour = bcdToDec(Wire.read() & 0b111111); //24 hour time
int weekDay = bcdToDec(Wire.read()); //0-6 -> sunday - Saturday
int monthDay = bcdToDec(Wire.read());
int month = bcdToDec(Wire.read());
int year = bcdToDec(Wire.read());
//print the date EG 3/1/11 23:59:59
Serial.print(month);
Serial.print("/");
Serial.print(monthDay);
Serial.print("/");
Serial.print(year);
Serial.print(" ");
Serial.print(hour);
Serial.print(":");
Serial.print(minute);
Serial.print(":");
Serial.print(second);
}