Servo - April 2013

www.servomagazine.com/index.php?/magazine/article/april2013_ThenNow

made completely from scratch with items such as 99-cent flashlights; he used soup cans for the eyes.

Dave told me, “I am always on the lookout for useful interesting things that I can use in my robots. The shoulders of Loki are made from carpet protectors that go under a couch’s legs. Loki’s drive wheels are lawnmower wheels I picked up at the hardware store. His tail-wheel is made from two inline skate wheels I caught on sale from a sporting good store. Trim around the robot is mostly door-edge molding from an auto parts store, as well as the decorative lighting on the sides of the robot. There are lots of interesting decorative lights at auto parts stores.” “I also scrounge the local surplus stores. Loki’s elbow rotation is supported by high quality bearing joints I picked up for $1 each. The shoulder motors use an expensive Kerr motor controller which I got surplus for $5, then learned how to program the thing from the company’s website. Loki’s blue shoulder brackets are also from the surplus store. Loki’s left hand was a gripper for picking up things I got from a drug store. His voice comes from an iPod dock speaker mounted just below the head. The grills on the side of the robot are florescent light cover panels from Home Depot, painted black. The grill on the font of the robot’s stomach is made from a bathroom vent cover (also painted black).” Dave uses a laptop computer as the brains for Loki, and also as a chest-mounted display. The PC uses Visual C++ and an onboard PIC relies on the CCS C compiler. Two Logitech laptop cameras serve as eyes for his stereo vision system.

Typical of most robot builders, projects never end as improvements are always envisioned and added. Figure 2 shows Loki's newer drive assembly using reliable Pittman gearmotors and a toothed belt to drive the wheels instead of the previous stepper motors.

There was a bit of machining required on the two 1/4” aluminum plates, but Dave used a heavy aluminum L extrusion to mount the plates. Iron angles would have interfered with the robot's compass.

That is the advantage of building your own robot from scratch — you can always change the structure and components as you locate better parts.

Dave has dramatically changed Loki from its birth in 2006 until now. Dave is a prime example of a robot builder who took common objects and made them fit into one of the finest robots that I have ever seen. Johnny Five from the film, Short Circuit was personable; however, I do believe Loki has far more actual personality than the movie action prop.

Dave and his daughter are 'Team Crash,' competing in the new SyFy series, Robot Combat League. For more information on Dave's many robotic creations, go to www.dshinsel.com.

Kenneth Maxon’s NeRP

I first met Ken at one of the Seattle Robotics Society's Robothons. He had a most amazing creation which is

FIGURE 2. New wheels and motors for Loki.

shown in Figure 3. His large bot, Max, had 12 stepper motors for motion and over 4,600 screws to hold it together. Figure 4 shows another remarkable robot that he has built.

Ken had a functional robot in mind when he designed it; one that could navigate around his block. Moreover, precision machining of the 6061-T6 aluminum stock into the shiny parts (shown in the figure) was critical to his design and to his desire for a truly beautiful work of art.

Figure 5 is a close-up of the robot's upper suspension. I could just stare at the robot for hours. Figure 6 shows four views of the robot’s ability to traverse obstructions using a rocker-bogey six-wheel system, similar to those used on the Mars rovers.