Page 270 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

gearbox motor. The circuit reads the level of illumination that the
robot sees. If the light level is high enough, it turns on the motor to
the gearbox. The trip level of the circuit is user adjustable using
potentiometer V1.
Gearbox
Before we get into the construction of the robot, let’s first look at
the gearbox (see Fig. 12.3). Physically, this gearbox is smaller than
many gearboxes and is easier to fit inside the sphere. It has a
1000:1 gear ratio. The higher the gear ratio, the slower the robot
will move.

Vcc Vcc Vcc Vcc

R3 C1
R1 .0047 Motor
33K

2
7 6 Tip
4 120
5
1
3 7 Q1
V1 249
4.7K R2 R4
15K 15K

12.2 Schematic of solar-ball circuit

12.3 Gearbox 1000:1 ratio
Team LRN Solar-ball robot