Micro SD Card Reader Module SPI Interface

The Micro SD Card Reader Module is a compact storage interface that allows microcontrollers to read and write files on a microSD memory card using Serial Peripheral Interface (SPI) communication.

It provides a convenient way to add removable data storage to Arduino projects, electronic monitoring systems, data loggers and embedded devices without requiring a computer to remain connected.

The module features a microSD card socket, six connection pins, an onboard 3.3V voltage regulator and signal-interface circuitry for communicating with compatible microcontrollers.

Whether you are building a temperature monitoring system, recording sensor readings, developing a smart agriculture project or creating a standalone data logger, this module makes it possible to save information for later retrieval and analysis.

Key Features

• SPI Communication: Uses the standard SPI protocol to communicate with a microcontroller.
• MicroSD Storage: Allows compatible microSD and microSDHC memory cards to store project data and files.
• Read and Write Functions: Supports creating, opening, reading and writing files through compatible software libraries.
• Onboard Voltage Regulation: Includes a 3.3V regulator for supplying the microSD card from the module’s external power input.
• Signal Interface Circuitry: Provides interface-level circuitry for integration with supported microcontroller systems.
• 6-Pin Header: Clearly labelled CS, SCK, MOSI, MISO, VCC and GND connections.
• Compact PCB Design: Suitable for embedded electronics and custom project enclosures.
• Four Mounting Holes: Provides convenient mounting points for securing the module.
• Arduino Library Support: Works with the standard Arduino SD library for file handling and data logging.

Technical Specifications

Pin Description

Applications

1. Arduino Data Logging

Record sensor readings automatically to a microSD card for later analysis. This is useful for school projects, engineering experiments and electronic measurement systems.

For example, connect the module to the Arduino Uno R3 Development Board to build a simple temperature or environmental data logger.

2. Temperature and Humidity Monitoring

Save temperature and humidity measurements at regular intervals without maintaining a continuous computer connection.

The recorded measurements can be stored in CSV format and later opened in Microsoft Excel or other data analysis applications.

3. Agriculture and Irrigation Projects

Store soil moisture readings, water level measurements and irrigation activity records for agricultural monitoring and automation projects.

4. Time-Stamped Data Recording

Combine the Micro SD Card Reader Module with the DS3231 RTC Real-Time Clock Module to attach accurate dates and times to recorded sensor measurements.

This is particularly useful for environmental monitoring, experimental research and automated equipment logs.

5. IoT and Embedded Systems

Provide removable local storage for supported embedded systems, including recording measurements when an internet connection is unavailable.

6. Robotics Projects

Store robot movement records, navigation information, configuration settings and other operational data for later analysis.

7. Electronic Instrumentation

Create simple recording instruments that save electrical measurements, event logs and experimental data for research or classroom demonstrations.

Connecting the Micro SD Card Module to Arduino Uno

The module communicates with Arduino Uno through the SPI pins.

To make wiring easier, use Male-to-Female Jumper Wires available from DIYGH.

After connecting the module, insert a compatible FAT16/FAT32-formatted microSD card and initialize it using the Arduino SD library.

The library provides functions for creating files, saving sensor readings, reading previously stored information and managing files on the card.

For additional programming information, consult the official Arduino SD Library documentation.

Important Usage Information

• Use a suitable, regulated 5V supply for this module’s onboard voltage regulator.
• MicroSD memory cards operate internally at 3.3V. Do not apply 5V directly to a bare memory card.
• For ESP32 and other 3.3V microcontrollers, verify the module’s supply and signal-level compatibility before wiring. Do not assume the regulator-equipped board operates correctly from a 3.3V VCC input.
• Format the memory card using a file system supported by the selected software library. FAT32 is a common choice for microSDHC cards.
• Avoid removing the memory card while data is being written.
• Close files properly in software to reduce the risk of corrupted data.
• Use a stable power supply to avoid unexpected interruptions during file operations.

Package Includes

• 1 x Micro SD Card Reader Module with SPI Interface

MicroSD memory card is not included.

Available from DIYGH Tech Hub, Apatrapa Junction, Kumasi, Ghana, for Arduino projects, robotics, IoT systems, electronic instrumentation and STEM education.