A couple of months ago I started playing with Eagle. Something I had always wanted to try but never had the time or courage to get started. After playing with Arduino’s and a Dagu Red Back Spider I had the idea to design a board with the ATmega328P-PU and a powerful 3A 5V switchmode regulator. That way I could easily attach a lot of servos to the board and not need to worry about how to power them.
I chose the LM2576 regulator because of its price, only 0,58$ @ Tayda electronics. It took me quite some time to learn Eagle and design what I wanted. I changed the design a dozen times, retraced the board a couple of times. But now I can say it was worth it. As you can see in the video the board can power 12 small micro 9G servos without trouble. The 5V line stays pretty stable. I was worried that the servos might cause the ATmega to reset, for that reason I put a lot of capacitors on the board. I don’t know if they really make a difference, but I had a lot of capacitors in my parts box so I might as well use them.
There is also a 3,3V low dropout voltage regulator on the board to power 3,3V devices. I also put a fuse on the board, I did not put it on the board to protect the ATmega. It has more to do with the fact that I will use a Lipo battery to power the board in my next robot. I’ve started designing a small hexapod with 2 DOF legs. The hexapod will use 12 micro 9G servos. So now that I have the electronics figured out it’s time to get the mechanical design ready.