The spider robot at the moment is simply a platform. I don’t have a purpose for it yet. I saw the designs on Instructibles.com and had to make one. The original platform was called Terra Spider. Its original purpose is to perform sampling of contaminated areas that may be too hazardous for humans to work. The concept is a group of these Terra Spiders would be delivered to an area via drone, or quadcopter. Once there they would work cooperatively to cover the area and sample the environment. I don’t have a use or interest in sampling but the platform intrigued me, so I modified it for my own use.
The robot is powered by two geared DC motors. These particular motors are from an inexpensive kit of geared motors put out by Make. I picked them up at, the now defunct, Radio Shack as they were shutting down their stores. They came in three gear ratios; fast with little torque, medium speed and torque, and slow with more torque. The fast ones didn’t work because there was too little torque. The high torque ones worked but were slow. So, I compromised… and run them at 12 volts instead of the intended 6. I don’t expect these to last very long before I replace them with something significantly better. These motors turn a gear in the center which turns another to which the legs are attached. Through a system of levers and the gears a walking motion is created.
The chassis is laser cut from 3mm and 6mm acrylic and bolted together using 6-40 and 1/4-20 screws and bolts. The acrylic makes for a nice light frame and is readily available from several suppliers in town. However I am finding the crystalline structure of the acrylic to be a bit brittle for this application. The parts are under a lot of torque both from the walking motion and side to side as it moves. This has caused one leg (currently super-glued together) and one of the levers (replaced) to snap. Ideally this would be cut in aluminum or another, less brittle material.
At the heart of the robot is an Arduino mictrocontroller and an Arduino motor controller shield. The Arduino is super easy to program and expand. Numerous shields, sensors, or other actuators are available to give this little robot any number of functions. At the moment it simply walks back and forth. If I can find a better material to use with this design I may make a number of them to walk around. To what purpose I don’t know yet. But they are fun.
For information and plans to build your own go to http://www.instructables.com/id/Terra-Spider-Autonomous-Remediation-Robot/?ALLSTEPS