SD Cards (Part 3)
Other posts on same subject Part 1, 2, 3, 4, 5, 6
Following the idea of minimizing the extra components required for building smart Arduino applications, here are some illustrations of the additional SD Card module that I am using for testing prototyping purposes (Pevious post).
This is the electronic schematic which makes use of simple resistor dividers to make the 5V output from Arduino compatible with the 3.3 V tolerated by the SD card. The Data out line from the SD Card goes straight to the Arduino without booster. The SD Card is supplied by the 3.3 V taken from the FTDI USB/Serial interface chip (cheap!). I could not manage to get errors out of this configuration in spite of intensive testing.
Note: If you plan to use multiple SPI devices on the same bus, consider feeding these devices with a separate +3.3V regulator wired tothe +5V
And this is a picture of the module. The socket has been hacked from a cheap card reader (1€ or so)
