UPDATE 2: For everyone still having problems finding the previous versions of the software, please refer to this page: https://www.arduino.cc/en/Main/OldSoftwareReleases#previous
UPDATE: This tutorial will work on Arduino IDE 1.0.1, the recent 1.0.5 makes some changes on the ISP sketch so I'm not sure if it will work (I just bought 2 ATMega328 and burned both on 1.0.1).
Please use 1.0.1 to eliminate any problems. Click Here
I had one remote controlled project that needed an Arduino running 24/7 but I didn’t want to leave my $32 Arduino UNO, so I decided to buy some pieces and created my own Arduino. The most important part was buying the microcontroller. These were my options:
ATMega328P-PU with Optiboot ~ $5.50 (Sparkfun) / $5.19 (Digikey)
ATMega328P-PU ~ $3.16 (Digikey)
ATMega328-PU ~ $2.88 (Digikey)
Obviously I bought the cheaper one, huge mistake. After some research I found that my first option was the straight one. Just plug it as a normal Arduino, the last two needed something else.
The last two options were missing something called a bootloader. A bootloader is “a small program that has been loaded on to the microcontroller. It allows you to upload code without using any additional hardware.”
So first if you were to do anything on those microcontrollers you need a bootloader burned on those chips. As you may have notice, the difference between the second and the third is just a mere P after the 328. This P means pico for picopower which is a technology ATMEL has developed that allows the microcontroller to run with less power.
Well if you see the microcontroller on your Arduino UNO you will find out that it is using the picopower micro, not the normal one. I bought 3 normal ones. OMG then I’m totally screw. Well no, you just have to make a pair of changes on your Arduino files to make it work.
This tutorial will teach you how.