After playing with Arduino for a while I thought about making my own PCB’s. I installed Eagle and tried to design some simple PCB’s. I actually learned to work with Eagle by watching Eagle tutorials on Youtube. I’ve had all my boards made in China so far. And I can’t complain, prices are very low and the quality seems very good. All my recent PCB’s have been made by Seeedstudio. They provide a DRC file for Eagle so it’s easy to check if your board complies with their standards.
The first board I designed was a simple “undershield” for an Arduino Nano. More info here.
This was the first PCB I designed that had a micro controller on it. I had already designed the above undershield. So the next thing I wanted to try was to make my own Arduinos.
The result is a simple break out board for the ATmega328P-PU or other ATmegas in DIP28 format. It has an FTDI and ICSP header to program the micro controller. There is also a led on pin 13 just like the real Arduinos All the digital and analog pins are brought out to male and female pins making it very easy to connect things to the ATmega.
I’ve used this design as a basis for my other PCB designs based on the ATmega328. As the board only has the basic components to make the micro controller work.
I did not bother to make it as small as possible, all the components are through the hole making it easy to solder. The board is not shield compatible with the original Arduinos.
The Arduino Duemilanove and Uno are based on the Atmel ATmega328P-PU micro controller, this chip comes in a 28 pin DIP format. Which is easy to solder, just put a socket on the board and plug the chip in. The biggest chip Atmel makes in DIP format is the ATmega1284. It is available in a big 40 pin DIP format and in SMD. And there is an Arduino bootloader for it So I could not resist and got me a whole bunch of these big chips I designed a simple break out board for it, the Bajduino 1284. Click on the image for more info about this board.
The Arduino boards are great for prototyping. They come with female headers which makes it easy to connect them to a breadboard. But when I started planning to built my first robot, the Dagu Rover 5 I realized that they aren’t very practical to built in to a project. I then bought a Dagu Red back spider controller, which is based on the Arduino Mega 1280. On this board every pin of the ATmega1280 is brought out to male pins, with a 5V and GND pin next to it. The Red back spider robot controller also has a big 3A 5V switch mode voltage regulator. This inspired me to design similar boards, hence the Bajduino 3A.
Bajduino Mega 3A
After building the Bajduino 1284 and 3A I made a new design combining the best of the 2 boards, with some extras. Combining an ATmega1284 with a powerful 3A switch mode regulator (LM2596). I also added a header for a wireless nRF24L01 module. Since that needs 3.3V I added a linear LM1117-3.3 voltage regulator. I have bought quite a number of I2C devices, some working at 3V3. So I added an I2C logic level converter consisting of 2 small mosfets and 4 resistors. The board is quite big, I did not put any time in making it as small as possible. This board has become my favorite prototyping platform. I always have one on my desk to to try out new stuff.