Micro SD Card Adapter Module With SPI Interface for Arduino

Specifications

• Operating Voltage: 4.5V - 5.5V (Onboard 3.3V LDO voltage regulator)
• Logic Level: 3.3V & 5V Compatible (Onboard level shifting circuitry)
• Supported Card Types: Micro SD (up to 2GB) & Micro SDHC (up to 32GB)
• Interface Type: Standard SPI (Serial Peripheral Interface)
• Mounting: 4x M2 positioning holes for easy enclosure integration
• Dimensions: ~ 42mm x 24mm x 12mm
• Pinout: VCC, GND, MISO, MOSI, SCK, CS (Chip Select)

Applications

• Environmental Data Logging: Record temperature, humidity, and GPS coordinates onto a text file.
• Audio Playback: Build a custom doorbell or prop using the TMRpcm library to play .wav files.
• IoT Web Servers: Store heavy HTML, CSS, and image files for an ESP32-hosted web server.
• CNC & 3D Printing: Feed G-code commands to stepper motor drivers without tying up a PC.

New Capabilities

• Past Projects: If you've mastered reading sensor data and printing it to the Serial Monitor, you are ready for this upgrade.
• Feature Upgrade: This module unlocks persistent memory. Instead of losing all your sensor readings when the power goes out, this product allows your hardware to log historical data indefinitely and transport it physically to a computer via the SD card.
• Effort Level: Intermediate. You will need basic knowledge of SPI communication and the standard Arduino SD.h library.

Virtual Technician & Wiring Guide

• ⚠️ Safety Warning: SD Cards natively operate at 3.3V. This module is Probots™ Logic-Safe, featuring a built-in level shifter IC (like the 74LVC125A). This safely drops your Arduino UNO's 5V logic signals down to 3.3V. However, you must supply 5V to the VCC pin so the onboard regulator functions correctly.

Arduino UNO Wiring:

• VCC ➔ 5V Pin (Do not use 3.3V)
• GND ➔ GND
• MISO ➔ Pin 12
• MOSI ➔ Pin 11
• SCK ➔ Pin 13
• CS ➔ Pin 4 (Default for most sketches, can be changed in code)

Package Includes: 

• 1 x Micro SD Card Adapter Module With SPI Interface for Arduino

Frequently Asked Questions (Technical FAQs)

• How should I format my Micro SD Card for this module?
  Always format your SD card to FAT16 or FAT32. The standard Arduino SD library cannot read exFAT or NTFS formats.
• What is the maximum storage size supported?
  The module supports Micro SDHC cards up to 32GB. Cards larger than 32GB (SDXC) typically use exFAT and are not natively supported by basic microcontroller libraries.
• Why is my SD.begin() function failing?
  The three most common reasons are: the SD card is not formatted to FAT32, the CS (Chip Select) pin defined in your code does not match your physical wiring, or the wiring is loose.
• Can I use a 3.3V microcontroller like an ESP32 or STM32?
  Yes. While the module is designed for 5V inputs (using an onboard regulator), it typically accepts 3.3V logic signals perfectly fine via the SPI bus. Feed 5V to the VCC pin if available.
• What is the default CS (Chip Select) pin?
  It depends entirely on your code, but the default Arduino examples use Pin 4. You can change this to any available digital pin by calling SD.begin(yourPinNumber).
• Can I use multiple SPI devices on the same board?
  Yes, SPI is a bus protocol. MISO, MOSI, and SCK can be shared among multiple devices (like an RFID reader and this SD module). However, each device must have its own unique CS (Chip Select) pin.
• Why does my Arduino reset when it tries to write to the SD card?
  Writing to an SD card can draw sudden spikes of current (up to 100mA-200mA). If your power supply is weak (like running directly off a cheap USB hub), the voltage drops, causing the Arduino to reset. Use a robust external power supply.
• Can I read standard-sized SD cards with this?
  No, the physical slot on this module only accepts Micro SD and Micro SDHC form factors.
• Can I hot-swap the SD card while the Arduino is running?
  It is highly discouraged. Pulling the card out during a write cycle will corrupt your files. If you insert a new card, you must call SD.begin() again in your code to initialize it.
• How fast can I log data using this module?
  Write speeds depend heavily on the microcontroller's SPI clock speed and the specific SD card's write latency. On a standard 16MHz Arduino UNO, expect a few kilobytes per second. Use the SdFat library for higher performance.
• Does this module work with Raspberry Pi Pico?
  Yes, wire the SPI pins to the Pico's hardware SPI pins and use a compatible MicroPython/C++ library to initialize the FAT file system.
• Can I play MP3 files using this module?
  Yes! You can store .wav files and play them back using the TMRpcm library, or interface this alongside a dedicated MP3 decoder chip for better audio quality.
• Are all the pins level-shifted?
  Yes, the onboard level shifter IC translates the logic levels for the critical SPI communication lines (MOSI, SCK, CS) from 5V down to 3.3V to protect the SD card.