I also started building my own clones. I've built some based on the ATmega328P and on the ATmega1284P. I'm not a fan of shields and don't use any. Shields wont fit in my boards. But it makes it easier to design a board I play a lot with servos, 3.3V I2C sensors and wireless nRF24L01 modules. So I designed a board with a 3A switch mode power supply, an I2C logic level converter and a header for the nRF24L01 module. And I put a row of 5V and GND pins next to most I/O pins. Makes it a lot easier to connect servos and sensors to the micro controller. I designed my boards in Eagle, not that hard to learn, and had the PCB's made by Seeedstudio. http://www.bajdi.com/wp-content/uploads/2012/12/bajduino-mega-3A.jpg
I play a lot with servos, so I designed my own board to make it more easy to test code and connect servo to the ATmega328. http://www.bajdi.com/bajduino/bajduino-3a-3/ It has 3A switch mode regulator so it can power a couple of servos without trouble. Has 3 rows of male pins for every input/output.
Cool walking action, that is quite an accomplishment.
LOL, so it can't carry it's own battery and so has to drag it along? Good thing it's not an aircraft.
The servos have enough torque to carry the battery. But the chassis is to small to fit my big 3S 3000mAh Lipo battery and all the electronics. I'm planning to use a slightly bigger chassis so the electronics and battery all fit inside/on top of the chassis.
This is my small hexapod with 2 DOF legs, it uses an ATmega328 to control the 12 servos of the legs. Another ATmega328 handles the wireless control (nRF24L01) and controls 1 servo (to sweep the ultrasonic sensor). The first ATmega measures the current drawn from the lipo battery via an analog sensor and measures the lipo voltage through a voltage divider. The second ATmega328 controls 3 RGB leds via transistors, measures the temperature of an LM2576 voltage regulator that powers the servos. It runs a PID loop that pwms a mosfet that powers a small fan to keep the regulator cool. Can't remember to which ATmega the ultrasonic sensor is hooked up The 2 ATmegas talk to each other over hardware serial. I've used almost all the pins on both ATmegas. I now very little about programming and used the standard servo library. It uses a very simple walking gait, no fancy coding.
I'm currently working on a bigger beast with 18 standard sized metal gear servos (MG996R). The servos are controlled by an Arduino Mega 2560. I've spent the last weeks understanding inverse kinematics and managed to write a walking gait only recently. The Mega has no problems controlling 18 servos. And its calculating a lot of floating point math for the inverse kinematics. I made the following video yesterday:
I bought a PCI5-S GPS module and antenna on Ebay for less then 15$. Tried it out last week and it works I soldered some wires to the PCIe card and connected it to an ATmega328 running at 3V3/8MHz. Uploaded one of the examples of the tinygps library and after 10 minutes it gave the right position. http://www.bajdi.com/my-15-gps-module/
I bought myself a Rigol DS1053E oscilloscope a couple of months ago. Very happy with it, I use it regularly. Sometimes just as an "advanced multimeter". I also have an Open Workbench Logic Sniffer. I bought it because I am playing with several I2C sensors and IC's. It's a very handy tool to debug code.
Oops I hadn't seen the pdf file I've just read it and cut the trace on my board. It was connected to ground just like yours. I've just uploaded the calibrate sketch and it works. Thanks for making the library and writing the pdf file. Not many libraries are that well documented