One of the earliest hobbyist uses for solar cells occurred in a phenomenon called BEAM (which stands for Biology, Electronics, Aesthetics, and Mechanics); these were analog robotics designed as if they were living things. Created in the 1990s by engineer Robert Tilden, BEAM was an attempt to make robots as simple as possible—no microchips or programs ran these bots. Instead, Tilden used discrete components, such as capacitors and resistors, to create sense-act behaviors. For example, the robot in Figure 4.3 senses light and then turns a motor.
FIGURE 4.3 This solar-powered robot spins when light strikes it.
Credit: Adam Wolf
The key to creating simple BEAM bots is tiny solar cells, which generate minute amounts of electricity; with the help of capacitors and other components, they generate enough electricity to move motors and turn on LEDs.
The biology aspect of BEAM comes into play because the robots frequently emulate insects and other living organisms. The circuits mimic the activities of biological neurons, and BEAM bots’ rudimentary control systems were intended to help the robots find food, just as a real being’s instincts might lead it to sustenance.
Tilden came up with three golden rules for BEAM robotics:
- Make your robot as simple as possible.
- Recycle and reuse junked electronics.
- Use solar power.
BEAM aficionados use scientific terms to describe the various types of robots. For instance, photophobes are robots that retreat from the light, whereas a thermophile is attracted to heat. They also describe the beam bots by locomotion style: crawlers, jumpers, rollers, and so on.