The SD Card Module for Arduino Projects

What is an SD Card Module?

An SD (Secure Digital) card module, also known as an SD card reader or SD card interface, is a hardware component that allows you to interface an SD card with a microcontroller or other embedded systems like Arduino. 

Here’s some information about the SD card module:

  • Purpose: The primary purpose of an SD card module is to enable data storage and retrieval on SD memory cards. SD cards are commonly used for data storage in various applications, including data logging, file storage, and data transfer.

  • Compatibility: SD card modules are designed to work with standard SD, SDHC (High Capacity), and SDXC (Extended Capacity) cards. They typically support different card sizes, including standard-size SD cards and microSD cards through the use of adapters.

  • Interface: SD card modules typically use the SPI (Serial Peripheral Interface) protocol for communication with microcontrollers like Arduino. SPI is a common serial communication protocol that allows for high-speed data transfer between the microcontroller and the SD card.

  • Power Supply: SD card modules require a 3.3V or 5V power supply, depending on the specific module. Make sure to check the voltage requirements of your module and provide the appropriate power.

  • Data Pins: These modules have pins for connecting to the microcontroller, including data pins (MISO, MOSI, SCK) for SPI communication, a chip select (CS) pin, and sometimes a voltage level conversion pin to interface with 5V microcontrollers.

  • Card Slot: The module typically includes a slot where you insert the SD card. Some modules have a locking mechanism to secure the card in place.

  • Level Shifting: Many SD card modules incorporate level shifting circuitry to allow them to work with both 3.3V and 5V microcontrollers.

  • Library Support: Arduino and other microcontroller platforms often have libraries available that simplify reading and writing data to SD cards using these modules.

  • Applications: SD card modules are commonly used in data logging projects, where they store sensor data or other information over time. They can also be used for file storage, such as storing images, audio files, or configuration data.

  • File Systems: SD cards are typically formatted with a file system (e.g., FAT16 or FAT32) to organize data. When using SD card modules, you often work with this file system to create, read, and write files.

When working with an SD card module and Arduino, you’ll typically use libraries like the “SD.h” library to interact with the SD card, making it relatively straightforward to implement data logging and file storage functionality in your projects.

Where to Buy:

You can pick some up from Amazon here: SD Card Modules

Don’t forget to pick up an SD Card too: SD Card

SD Card Module Connections

SD card module

If you already own the SD Card module, your pins may look slightly different but don’t panic, they are easily defined.

    • CD = Card Detect.

    • DO, SD-DO, MISO = SPI Master in slave out

    • GND = Ground

    • SCK, SCLK, Serial Clock = SPI Clock

    • VCC = Power input

    • DI, SD-DI, MOSI = SPI Master out slave in

    • CS = Chip select

Testing the SD Card and Module:

Assemble your components to the Arduino just like the image below, use the above descriptions if your pins read differently.

sd build 1

First, format your SD-card to Fat-32 on your home computer. Here is a great SD-Card formatting program SDHC formatter.

Once formatted to Fat-32, insert your newly formatted SD-card into the SD-card module.

The Cardinfo Sketch:

Now, open your Arduino IDE and follow this path:

File > Examples > SD > Cardinfo.

The Cardinfo sketch should open. Now upload this sketch to your Arduino board and then open the serial monitor.

good Card

Take a close look at the image above. If you received this message, everything worked.

format Card

Take a close look at the image above. If you received this message, the wiring was correct, the SD was detected but the filesystem is wrong. Try formatting it again with the Fat-32 filesystem.

bad Card

Take a close look at the image above. If you received this message, either your card is bad, or your wiring is incorrect. Check all connections and format SD card again with the Fat-32 filesystem.

If problems persist, double check your wiring connections, mistakes happen. Try a different Arduino, try a different SD card, try a different SD card module, to eliminate the cause of the problem.


The Elegoo Super Starter Kit

If you don’t already own any Arduino hardware, we highly recommend this kit as it has everything you need to start programming with Arduino. You can find out more about this kit, including a list of its components here: Elegoo Super Starter Kit

You can find this kit on Amazon here: Elegoo Super Starter Kit

The 0.96-inch Mini-OLED Display

We highly recommend this mini-OLED bundle of five 0.96-inch OLED displays. We have bought these before and they all worked perfectly. You can read more about the mini-OLED here: Mini-OLED

You can find this bundle on Amazon here: OLED Displays

Elegoo Nano (Arduino Compatible)

We have bought these Nano boards many times and can highly recommend them. There are three Nano boards in this pack making them a total bargain for everyone.

You can find this pack on Amazon here: Arduino Nano


Luke Barber

Hello, fellow tech enthusiasts! I'm Luke, a passionate learner and explorer in the vast realms of technology. Welcome to my digital space where I share the insights and adventures gained from my journey into the fascinating worlds of Arduino, Python, Linux, Ethical Hacking, and beyond. Armed with qualifications including CompTIA A+, Sec+, Cisco CCNA, Unix/Linux and Bash Shell Scripting, JavaScript Application Programming, Python Programming and Ethical Hacking, I thrive in the ever-evolving landscape of coding, computers, and networks. As a tech enthusiast, I'm on a mission to simplify the complexities of technology through my blogs, offering a glimpse into the marvels of Arduino, Python, Linux, and Ethical Hacking techniques. Whether you're a fellow coder or a curious mind, I invite you to join me on this journey of continuous learning and discovery.

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