How to save data to SD card using Memory Shield Module SPI

Question

I am trying to save some data to the SD card using the memory shield module that I read from HC-SR04 Ultrasonic Module. The data that gets printed indicates error. This is how my SD card module is connected.

SD card attached to SPI bus as
VCC -Arduino 5v
GND- Arduino GND
MOSI - pin 11
MISO - pin 12
CLK - pin 13
CS - pin 4

Still, Arduino complains that there was an error opening the file in SD card. My sketch is this:

#include <SPI.h>
#include <SD.h>
#define echoPin 6 // Echo Pin
#define trigPin 7 // Trigger Pin
int maximumRange = 250; // Maximum range needed
int minimumRange = 1; // Minimum range needed
long duration, distance; // Duration used to calculate distance
const int chipSelect = 4;
void setup() {
 Serial.begin (9600);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
 Serial.print("Initializing SD card...");
 // see if the card is present and can be initialized:
 if (!SD.begin(chipSelect)) {
 Serial.println("Card failed, or not present");
 // don't do anything more:
 return;
 }
 Serial.println("card initialized.");
}
void loop() {
 readDistance();
 if(distance>minimumRange && distance < maximumRange){
 String string = "distance is" + distance;
 // open the file. note that only one file can be open at a time,
 // so you have to close this one before opening another.
 File dataFile = SD.open("datalog.txt", FILE_WRITE);
 // if the file is available, write to it:
 if( dataFile ){
 dataFile.println(string);
 dataFile.close();
 Serial.println( string );
 }else{
 // if the file isn't open, pop up an error:
 Serial.println("error opening datalog.txt");
 dataFile.close();
 }
 }else{
 Serial.println("Out of range...");
 }
 delay(50);
}
int readDistance(){
 digitalWrite(trigPin, LOW); 
 delayMicroseconds(2); 
 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10); 
 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);
 distance = duration/58.2;
} 

Output:

rror opening datalog.txt
rror opening datalog.txt
error opening datalog.txt
rror opening datalog.txt
error opening datalog.txt
error opening datalog.txt
error opening datalog.txt
error opening datalog.txt
error opening datalog.txt

How do I solve this to save the readings to SD card?

• Chris Stratton: Re-opening the file each time through the loop seems like a bad idea. Unfortunately file system abstractions don't map very well to what you want to do. You may want to write a number of readings, then re-open a file, perhaps with a different name in an incrementing pattern. Or you could skip the filesystem and write to raw blocks. Most practically, have a look at the code typically used with Arduino-based uSD data loggers and see what you can learn from how they handle it.
• Maxthon Chan: I think you have fried your SD card. Those cards operate at 3.3V and may not be 5V tolerant.

Answer 1

Is there any print out based on this;

Serial.print("Initializing SD card...");
// see if the card is present and can be initialized:
if (!SD.begin(chipSelect)) {
 Serial.println("Card failed, or not present");
 // don't do anything more:
 return;
}
Serial.println("card initialized.");

Solution;

Try change

const int chipSelect = 4; // change value to 10

If not, try change the above code to;

Serial.print("Initializing SD card...");
if (!SD.begin(10)) {
 Serial.println("Initialization failed!");
 while (1);
}
Serial.println("Initialization done.");