How many memory do I need?

If I want to use SD card and use library…
for example I will use this SDWebBrowse/SDWebBrowse.pde at master · adafruit/SDWebBrowse · GitHub
(it is from

There are such lines
#include <SdFat.h>
#include <SdFatUtil.h>
#include <Ethernet.h>

What is their weight?

I must use Arduino Mega2560 (256KB) or Uno (32KB) is enough?

Also I will use RFID … and I will use library for working with it!

Guys, please, tell me. What do you think? :’(

  1. your talking about storage space on the chip not the amount of ram on the chip (the 328 has 32kb of storage, and 2k of ram for instance)

  2. really depends on what your doing, if your just nabbing a little bit of data and storing it to SD then it does not matter much as your sketch probably will not eat up a bunch of storage or ram, more complex applications will

more info please

My application will receive IDs from ethernet and store them on SD card. And in the same time it will check RFID reader... and if there was read ID of card... then try to find this ID in SD card... and if ID is there then open the door.

Program will check in loop the passed time... and each 1 minute will check server on new IDs. I need to know how many place located standard application that use RFID library (just for getting ID) and also library for SD card (FAT or something like this ) for finding ID and for write new and delete old ID.

Guys, please, tell me. What do you think?

I think you should copy a sketch that uses both SDcard and ethernet and press compile button. You don't need a board to test compile what you want. Just download the IDE (select a board) and compile.

From my mind I would say both libs use about 8-10 KB so a 328 - 30K NB 2K bootloader - an UNO has a even smaller bootloader.

If I listen to your requirements I expect it to fit in a 328 but it depends on your coding skills too :)

Here's my take: If you expect to expand your current project drastically beyond 3000 lines of code (rough estimate), you should use a MEGA. I have, in a project, used EEPROM, liquidcrystal, wire, sprintf, and few other libraries. I expect to fill my 328 chip FLASH when I reach about 3000 lines. Well for that project, I've got 2,500 lines already. I only have space for about 500 more lines. Compile your current code, discount the compiled bytes and roughly count each line of code you add as 10 bytes.

If you run complicated calculations with lots of layers of variables (especially arry) and subroutines, you should be concerned with SRAM, which is only 2KB for 328 and 8KB for MEGA(right?)

Thanks guys and girls... I have done it... This example take 16KB ... it is half of Arduino Uno memory ... so!!! I need just her!!!! ;D

I included library SdFat and all have compiled nice! I am genius (right?).

Just hold your victory dance right there, make sure you have called all the library functions that you will be using in your actual code. Even when you include a library, the functions that are not called are not compiled. Later in your actual code if you use these functions, they start to count in the final size.