Hello All:
I'm sure you've heard this a few times before. I'm new to the Arduino platform and need some help. I'm using the Sparkfun Inventor's kit which uses an Arduino Uno along with a Sparkfun MicroSD shield. Using the template application under SD->Datalogger, I get a file with random numbers as is expected. (The Datalogger reads three analog sensors (not attached) and writes their values to the SD card in a txt file called "datalog.txt".
The issue is that I wrote another application for it using a temperature sensor. The hardware and measuring sides of the app work fine however the only thing that does not work is the SD card write routine. When I let the logger run for a bit then stick the SD card into my computer, the computer shows an empty datalog.txt file despite the serial output and the sd card write are within the same block of code. (I'm not writing NULL values to the SD card).
A question I have concerning the SD card is that although I can see the sd.start command, there doesn't seem to be any command to stop or to flush the SD card. Is there such a command or workaround that might explain the lack of data in the datafile?.
Please find my code below.
Thanks in advance.
FIRESTORM_v1
=============================
/*
This is a basic SD card temperature monitor logger. It uses the SD card shield for datalogging,
two pushbuttons, two LEDs and the TMP36 temperature sensor to detect and log temperatures to the SD card.
Pin definitions are as follows:
A0 - Temperature sensor (D14)
D0 - Red LED
D1 - Yellow LED
D2 - SD card switch (BTN1)
D3 - Datalogger Start/Stop (BTN2)
D8 - CS for SD card
D11- MOSI for SD card
D13- SCK for SD card
*/
// Includes
#include <SD.h>
// Variable Declarations
// This is required per the SD documentation. Without it, the SD library will not work.
const int chipSelect = 4;
//Physical devices
int SDmount = 6; //SD card mount LED
int Heartbeat = 7; // Heartbeat LED
int SDbutton = 2; // Bottom button
int DLbutton = 3; // Top Button
int TempSensor = 14; //analog 0 Temperature Sensor
//Other Variables
boolean SDEnable = 0; // SD card mounted?
boolean DLRun = 0; // Datalogger running?
int val = 0; // Temporary variable for reading buttons
File datafile; // File structure for datafile
void setup() {
// Start Serial communications for debugging.
Serial.begin(9600);
Serial.print("Device ready. Hit SW1 to mount SD card.\n");
pinMode(SDmount, OUTPUT);
pinMode(Heartbeat, OUTPUT);
pinMode(SDbutton, INPUT);
pinMode(DLbutton,INPUT);
}
void loop() {
if (SDEnable == 1 ) {
if (DLRun == 1) {
digitalWrite(Heartbeat, HIGH); // Turn on Heartbeat LED.
// Read the temp sensor, perform basic math to convert to fahrenheit.
float temperature = getVoltage(TempSensor);
temperature = (temperature -.5 ) * 100; // convert from 10mv/deg
temperature = ((temperature * 9 ) / 5) + 32; // Convert to fahrenheit
// Write our acquired data to the SD card's datalog.txt file.
File datafile = SD.open("datalog.txt", FILE_WRITE); //Open file
if (datafile) {
datafile.println(temperature); //Print to file
Serial.println(temperature); // Print to serial port
datafile.close(); //Close file
} else {
Serial.println("Something went horribly wrong. You managed to start the SD card but can't write.");
}
// Turn off the heartbeat LED.
digitalWrite(Heartbeat, LOW);
}
}
val=digitalRead(SDbutton);
if (val == LOW) {
if(SDEnable == 0) {
Serial.print("Initializing the SD card....\n");
if (!SD.begin(chipSelect)) {
Serial.println("Card failed, or not present");
} else {
Serial.println("Card is mounted.");
if (SD.exists("datalog.txt")) {
Serial.println("datalog.txt exists, continuing.");
} else {
Serial.println("datalog.txt did not exist, creating it now.");
datafile= SD.open("datalog.txt", FILE_WRITE);
datafile.close();
}
digitalWrite(SDmount, HIGH);
SDEnable = 1;
}
} else {
if(DLRun== 1) {
Serial.print("Stop the datalogger before unmounting!\n");
} else {
Serial.print("Here is where we would unmount the SD card.\n");
digitalWrite(SDmount,LOW);
SDEnable = 0;
}
}
}
val=digitalRead(DLbutton);
if (val == LOW ) {
if(DLRun == 0) {
Serial.print("Starting Datalogger.\n");
if(SDEnable == 0) {
Serial.print("Warning! Datalogger will not start with SD card not mounted.\n");
} else {
DLRun = 1;
}
} else {
Serial.print("Stopping Datalogger.\n");
DLRun = 0;
}
}
delay(1000);
}
/* getVoltage function
*/
float getVoltage(int pin) {
return(analogRead(pin) * .004882814);
// convert from 0 to 1024 digital range to 0-5VDC each 1 reading = ~5mV
}
