Arduino YL-30 SD Card

I’ve bought two Arduino SD Cards modules from and didn’t found any info for them – So I decided to try by my self.

Reading a bit about Arduino SD cards i found out that Arduino SD card uses SPI (Serial Peripheral Interface) to communicate with the SD Cards and with Arduino UNO (along with others – except Mega) those PINs are 11, 12 and 13.

SPI connections always have a master (usually a microcontroler) and a slave device.  Typically there are three lines common to all devices (and this SD card reader to):

MISO (Master In Slave Out) The slave line for sending data to the master
MOSI (Master Out Slave In) The master line for sending data to the peripherals
SCK (Serial Clock) The clock pulses synchronize data transmissions generated by the master

More info on the SPI, you can check the Arduino Documentation.

About the SD Card, must be FAT16 or FAT32 formated.

The YL-30 SD Card Reader



This SD Card reader – Arduino Compatible – has some perks.  All the PINS must be connected, even the 3.3V and +5V.

The wiring will be as follows:

YL-30 SD PINs Arduino PINs
SCK 13
CS 4 (It’s custom to be PIN 4)
3.3V 3.3V
+5V 5V



Now, just insert a SD card a let’s start Arduino IDE and write the code from Arduino tutorials about SD Cards – The Code is for a Ethernet Shield with a onboard SD Card – but it works perfectly here.

After compiling and uploading the code to the Arduino, here’s the result (I have no files in the card):



And here’s the finished contraption: