In it's shortest form the Philosophy of BEAM Robotics is:

• Use minimalist electronics,
• Recycle & reuse components out of technoscrap, and
• Use radiant energy like solar power.

Why build a robot around these guidelines? Well, because it's inex- pensive, robust, effective, and radiant energy like solar power means no batteries. And since an average BEAM robot costs under $20, it's an excellent way of making the first steps in Robotics.

Building small BEAM robots is easy, but can still become highly com- plex, and building larger ones is not as simple as it looks.

Acronym BEAM
The acronym BEAM is standing for: Biology, Electronics, Aesthetics, Mechanics. In relation to this robotical approach the terms have the meaning as follows:

• Biology: We look to the nature for inspirations, keeping in mind that it didn't have some of the techniques we have available, like wheels and bearings, but more important found fascinating solutions for many problems.
• Electronics: Electronics is the only available technology to us other than eg. microsurgery on living organisms to get our creations to do what we want.
• Aesthetics: Aesthetics means that something "looks cool". Sure, something crappy may work, but it's worth the extra effort to get it as nice as can be. You never see a forest critter roaming around with a leg duct-taped on.
• Mechanics: This is the secret of many successful BEAMbots. With an intelligent design, you don't require additional sensors to get around without optical or touch switches, for example.

Basic Principles
The basic principles of BEAM rest on the fact that to build smart machines one must first build smart bodies and that this approach primarily relies on simple analog circuits instead of microprocessors or microcontrollers.

Simple Analog Circuitry
To think that just because BEAM robots are electronically simpler than an average wristwatch implies they aren't capable is wrong, indeed they are. Robots as complicated as 8-jointed, 4-legged walking spiders have been built following the philosophy and using the principles of BEAM.

The two most common technologies are Solar Engines and Nervous Networks (Nv Nets).
The simplest of BEAM robots can be constructed around a two tran- sistor circuit called the Solar Engine, which ingests light and turns it into bursts of movement at the frequency of anywhere from some bursts a second to a burst a day, depending on how it is configured.
More complex BEAMbots are based on Nervous Networks (Nv Nets), in which a BEAM neuron is a resistor-capacitor network and a logic gate.

Publication

• Hasslacher, Brosl and Tilden, Mark W.: Living machines [PDF]