Page 268 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

Solar-ball robot 12

THE INSPIRATION FOR THIS ROBOT ORIGINALLY BEGAN WITH
Richard Weait of North York, Toronto. Richard created a light-
seeking robot in a transparent globe (ball). More recently, Dave
Hrynkiw from Calgary, Canada, picked up the ball (so to speak)
and developed a series of light-seeking mobile solar-ball robots.
There are two features to this mobile robot that are interesting
(see Fig. 12.1). First is the method of locomotion. Inside the globe 247
is a gearbox. One end of the gearbox’s shaft is secured and locked
to the inside of the inner surface of the transparent globe. The
shaft being locked cannot rotate, which forces the gearbox itself to
rotate. The gearbox is heavy, which moves the center of gravity of
the sphere forward. In doing so, the sphere moves forward.
When at rest, the weight of the gearbox keeps it at bottom dead
center (the gearbox facing down), and the ball resists rolling.
When the gearbox is activated, the box begins to rotate inside the
globe. This moves the center of gravity of the ball forward, causing
the ball to roll forward.
The second feature relates to the power supply for the gearbox. The
original solar robots had an onboard power supply that provided
intermittent power to the gearbox. (For more information on this
type of power supply, see Chap. 3.) The onboard power supply
consists of a solar cell, a main capacitor, and a slow oscillating or
trigger circuit. When exposed to sunlight, the solar cell begins
charging the circuit’s main capacitor. When the capacitor reaches
a certain voltage, a trigger circuit dumps the stored electricity
through a high-efficiency motor connected to the gearbox, causing
the robot to move forward a little.

Team LRN Solar-ball robot

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