Simple, Cheap Robot (Video)
Okay, we want to buy or build a humanoid robot with movable hips, body, shoulders, and elbows. In terms of our design budget, how many degrees of freedom and servos, how sophisticated a controller, and how much money should we budget?
Would you believe zero servos, no controller, and a total budget of just under two dollars?
About a week ago we were wandering the back streets of "AKIBA" - the well known Akihabara district of Tokyo, and happened to pop into a small, hole-in-the-wall, recycle toy shop. Of course, we're a total sucker for anything that even faintly resembles a robot, and two small toys immediately caught our eye.
The shop keeper assured us that the cute little robot toys were designed in Japan quite a few years ago, though we wouldn't be surprised to find out that they were manufactured in China or someplace else around Asia. Unfortunately there is absolutely no marking anyplace on the robots.
It didn't take any encouragement on his part for us to open our wallet and immediately buy both of the robots he had available. Of course the price was right - only 100 yen each - so less than a dollar per robot toy.
Like many of the toys and toy robots we enjoyed as kids, the robots are powered by a windup key motor. They don't run long - usually less than 30 seconds or so, and there is no governor mechanism, so as the windup spring tension drops the robot just goes slower and slower. Still, they are a lot of fun to play with.
The linkage design that gets the movement from the body mounted motor out to the legs and arms is a really neat design. Robust enough to stand up to kids playing with it, and forgiving when people with large hands, like us, grab it and try to move things in directions they were never intended to go.
We even tried staging a little one-on-one fighting action, ROBO-ONE style. It was fun, but getting and keeping both robots going at the same time was a major challenge.
Here's what they look like in action:
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