Roboduino Tank Tread Base
We finally have our base for the Roboduino. I made a post to our site at: http://arduinofun.com/blog/2009/03/01/roboduino-base/
The Robot Rover for Arduino (Tank Kit) we ordered came in this weekend. Its designed for use with the Arduino and DC motors. Since we wanted to use servos with our Roboduino, we had to make a slight hack to the frame. I have added a few pictures to this post to show the modifications.
In photo 1, you can see the side of the base with holes that were designed for the DC motors. We made a template of the servo hole from the top of the base and then traced it onto the side. Once you make this cut, you will not be able to use the DC motors with this base easily anymore.
In photo 2, we used a Dremel and cut out the slot for the servo to fit into. Its better to cut inside the line and then file it down to fit afterwards. As you can see, the bottom is very close to the edge and can easily be bent with slight pressure so be careful. After we made the cut, we marked off where the holes to mount the servo would be and then drilled those out.
Carefully file down any areas that are rough and stop the servo from easily sliding into the mounting hole. You will need to use some mounting hardware to hold the servo in place. Since the base was designed for DC motors, it will not have these. We used 4-40×1 Flat slotted with nut bolts from Lowes. Now that you have the rear servos mounted you can add the front track wheel and treads. You will notice that the front wheels are closer to the base since there is no servo here. To easily fix that, just add a few washers and they will now be parallel with the rear track wheel. If you were using the DC motors, each track uses 20 treads. With your servo modification, you will use 19. Lay the base down, place the Roboduino on top where you would like to mount it, mark of the drill holes, and then drill those out and add some standoffs to secure the Roboduino to the top.
I will post more progress as we go along. In the main photo you can see we added a small breadboard to put the Xbee on. Our next step is to start testing controlling the robot with a Will Nunchuck and wireless. We will have the Arduino Duemilanove hooked up to the Wii Nunchuck and sending the commands to the Roboduino for navigation. At least that is what we hope to do!