Arduino: Nano
Modules: RTC DS3231, SD card Module, and RFID RC-522
I am very new to Arduino and currently building my first project, a device to that allows you to log times in order to clock in and out of a location. My code and circuit appear to working, however after the first time I return the SD to my computer, the data file will no longer update when I plug it back into the SD module. If i reupload the code to the Arduino, this solves the problem until the next time I remove the SD. In other words, I will upload the code, and be able to scan my RFID, this gives me the data for that RFID UID along with the time and date down to the minute. As long as I keep the SD card in its module the SD will still save data from new RFID scans. However, once I remove the SD card and place it in my computer, check the file, then return the SD to the module, any new scan I do of the RFID does not save its data on the SD card, unless I completely reupload my code to the Arduino. What can I do to fix this?
I derived my device and code from a similar project that I found a tutorial for online:
Here's my variation of the code:
#include <MFRC522.h> // for the RFID
#include <SPI.h> // for the RFID and SD card module
#include <SD.h> // for the SD card
#include <RTClib.h> // for the RTC
// define pins for RFID
#define CS_RFID 10
#define RST_RFID 9
// define select pin for SD card module
#define CS_SD 4
// Create a file to store the data
File myFile;
// Instance of the class for RFID
MFRC522 rfid(CS_RFID, RST_RFID);
// Variable to hold the tag's UID
String uidString;
// Instance of the class for RTC
RTC_DS1307 rtc;
//Variable to hold user check in
int userCheckInHour;
int userCheckInMinute;
// Pins for LEDs and buzzer
const int greenLED = 7;
void setup() {
// Set LED as outputs
pinMode(greenLED, OUTPUT);
// Init Serial port
Serial.begin(9600);
while(!Serial); // for Leonardo/Micro/Zero
// Init SPI bus
SPI.begin();
// Init MFRC522
rfid.PCD_Init();
// Setup for the SD card
Serial.print("Initializing SD card...");
if(!SD.begin(CS_SD)) {
Serial.println("initialization failed!");
return;
}
Serial.println("initialization done.");
// Setup for the RTC
if(!rtc.begin()) {
Serial.println("Couldn't find RTC");
while(1);
}
else {
// following line sets the RTC to the date & time this sketch was compiled
rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
}
if(!rtc.isrunning()) {
Serial.println("RTC is NOT running!");
}
}
void loop() {
//look for new cards
if(rfid.PICC_IsNewCardPresent()) {
readRFID();
logCard();
}
delay(10);
}
void readRFID() {
rfid.PICC_ReadCardSerial();
Serial.print("Tag UID: ");
uidString = String(rfid.uid.uidByte[0]) + " " + String(rfid.uid.uidByte[1]) + " " +
String(rfid.uid.uidByte[2]) + " " + String(rfid.uid.uidByte[3]);
Serial.println(uidString);
// Light LED when a card is read
digitalWrite(greenLED, HIGH);
delay(2000);
digitalWrite(greenLED,LOW);
}
void logCard() {
// Enables SD card chip select pin
digitalWrite(CS_SD,LOW);
// Open file
myFile=SD.open("DATA.txt", FILE_WRITE);
// If the file opened ok, write to it
if (myFile) {
Serial.println("File opened ok");
myFile.print(uidString);
myFile.print(", ");
// Save time on SD card
DateTime now = rtc.now();
myFile.print(now.year(), DEC);
myFile.print('/');
myFile.print(now.month(), DEC);
myFile.print('/');
myFile.print(now.day(), DEC);
myFile.print(',');
myFile.print(now.hour(), DEC);
myFile.print(':');
myFile.println(now.minute(), DEC);
// Print time on Serial monitor
Serial.print(now.year(), DEC);
Serial.print('/');
Serial.print(now.month(), DEC);
Serial.print('/');
Serial.print(now.day(), DEC);
Serial.print(' ');
Serial.print(now.hour(), DEC);
Serial.print(':');
Serial.println(now.minute(), DEC);
Serial.println("sucessfully written on SD card");
myFile.close();
// Save check in time;
userCheckInHour = now.hour();
userCheckInMinute = now.minute();
}
else {
Serial.println("error opening data.txt");
}
// Disables SD card chip select pin
digitalWrite(CS_SD,HIGH);
}(Code tags added by Moderator)