Fluffy

Fluffy was my first walking robot, and I think one of my most successful robots over all. Fluffy is built off a crust-crawler quadruped kit that has since been discontinued. On top of the kit I added a lexan sheet cut to hold a spin studio board above the main frame, and a rotating Ping ultrasonic sensor below the board in front.

I think the success of this robot comes from combining crust-crawler frame with the spin studio board. The frame kit is really meant to be a hexapod. They have stopped selling it with four legs, and I can understand why. Of servo based walking robots, hexapod designs are by far the most functional. Because they can walk with an alternating tripod gate they are easy to keep stable. Because they have six legs, they tend to be able to carry a fairly large payload with even weak servos. If you are thinking about putting any sensors or extra electronics on a walking robot, I recommend starting with a hexapod.

I was interested in doing a quadruped robot because I thought it would be more challenging to write walking code for, and it was. A lot of my professional background is in software development, so I am much more comfortable with math and software than anything mechanical. I often wish that somewhere along the way in my life I had taken a shop class! I am terrible with tools. But the challenge of programming a four legged robot to walk around has never been too bad.

The other successful element has been the Spin Studio card. The Propeller chip from Parallax is an excellent chip for hobby robots, particularly walking ones. Because you have eight processors all running with consistent timing, it is easy to set one processor to manage the servos, one to monitor the sensor, one to monitor the compass, and so on. The Spin Studio card is nice because you can switch out boards or create your own. It is easy to reuse or exchange electronic components.

For fluffy I made a board with a compass to aid in navigation:

Because of the good setup for input and output, and the abillity to exchange components, I sometimes use Fluffy as a test bed for software. You can see a good example of this when I was testing GWS gyro.