This example shows how to log data from three analog sensors to an SD card using the SD library.
The circuit: * analog sensors on analog ins 0, 1, and 2 * SD card attached to SPI bus as follows: ** MOSI - pin 11 ** MISO - pin 12 ** CLK - pin 13 ** CS - pin 10
created 24 Nov 2010 updated 2 Dec 2010 by Tom Igoe
This example code is in the public domain.
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#include <SD.h>
// On the Ethernet Shield, CS is pin 4. Note that even if it's not // used as the CS pin, the hardware CS pin (10 on most Arduino boards, // 53 on the Mega) must be left as an output or the SD library // functions will not work. const int chipSelect = 10;
void setup() { Serial.begin(9600); Serial.print("Initializing SD card..."); // make sure that the default chip select pin is set to // output, even if you don't use it: pinMode(10, OUTPUT);
// 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() { // make a string for assembling the data to log: String dataString = "";
// read three sensors and append to the string: for (int analogPin = 0; analogPin < 1; analogPin++) { int sensor = analogRead(analogPin); dataString += String(sensor); if (analogPin < 2) { dataString += ","; } }
// 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(dataString); dataFile.close(); // print to the serial port too: Serial.println(dataString); } // if the file isn't open, pop up an error: else { Serial.println("error opening datalog.txt"); } }
