Micro SD Card Reader Module – Arduino Compatible User’s Guide

Overview

This module allows your Arduino to read and write data to a microSD card using the SPI interface. It’s perfect for data logging, sensor storage, and lightweight file handling.

Features

• MicroSD card slot (supports FAT16/FAT32 formatted cards)
• Voltage regulator (accepts 3.3 V or 5 V input, outputs 3.3 V for SD card)
• Level shifters for safe 5 V → 3.3 V logic conversion
• 6‑pin header for easy connection to Arduino

Pinout

Setup Steps

1. Connect Pins:
   • CS → D10
   • SCK → D13
   • MOSI → D11
   • MISO → D12
   • VCC → 5 V (or 3.3 V if preferred)
   • GND → GND
2. Insert microSD Card (formatted FAT16/FAT32).
3. Install Arduino Library: SD.h (built‑in).
4. Upload Example Sketch:

   #include <SD.h>
   
   const int chipSelect = 10;
   
   void setup() {
     Serial.begin(9600);
     if (!SD.begin(chipSelect)) {
       Serial.println("SD card initialization failed!");
       return;
     }
     Serial.println("SD card ready.");
     File logFile = SD.open("log.txt", FILE_WRITE);
     logFile.println("Hello, SD card!");
     logFile.close();
   }
   
   void loop() {
     // Add sensor logging here
   }
   

5. Check Serial Monitor for confirmation.
6. Remove SD Card and read files on your computer.

Troubleshooting

Tips

• Keep SPI wires short (<10 cm) to avoid noise.
• Use shielded wires if logging in noisy RF environments.
• Always call logFile.close() after writing to prevent corruption.
• For multiple modules, assign different CS pins.