Thephotovore 1249015012.pdf

Porcupine Series

The Photovore
A (not so) brief introduction
Salvador Garcia Jul. 30, 2009

Copyright©, 2007, 2009 Noemi and Salvador Garcia Some material was copied from diverse sources on the ‘Net. Links to source, specifically the circuits and the pictures at the end of this text, provided where possible. Copyright covers all original text and images. Images, pictures and text obtainedfrom external sources is clearly indicated and copyrighted by their original owner/designers.

Introduction
The Photovore is a BEAM robot that is in most cases powered by the sun or artificial light, although there are some that use batteries. What is a Photovore? A Photovore is any thing that seeks out light. Have you seen how moths are attracted to the light? They can be called Photovores,although the more correct English word is phototropic. Obviously, in our case, a Photovore is a robot that seeks out light. This kind of robot usually does not use any kind of battery or an ON/OFF switch. Once it is built (or created?) it starts collecting energy from a light source and when it has enough it moves towards the light. It repeats this over and over again, always looking for a betterlight source.

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What is BEAM? BEAM is a certain way of thinking when building a robot. Most robots are built around a central “thinking” device. We could call it a very simple brain. Those that know about electronics call it a “processor”. The whole idea of a robot that uses a processor is that the builder assembles a bunch of instructions that tell the processor what to do. This bunch ofinstructions is called a “program” and this program is what tells the robot how to behave and react to external events. The BEAM philosophy is a group of concepts that describe a robot. This technology was patented by Mark Tilden. In 1989 he started experimenting with a methodology that could be used to design simple robots that did not use a processor, but still exhibited certain behaviors that werepreviously thought to need a central processing unit. He always saw the possibility of a machine using simple components (that is, no processor) and exhibiting life-like behaviors. BEAM tells us that a robot doesn’t really need a brain to behave a certain way. It goes further by saying that the simplest type of robot should react to its surrounding very much like animals do, specifically insects.Ok, pop quiz! What happens when you see a fly sitting somewhere and try to grab it with your hand? It flies away! The fly knows that something is getting close to it and reacts by flying away (better safe than sorry!) The idea of BEAM robotics is that the robot, without using a processor should have some behaviors that are similar to those of insects or other animals. And so, that gives us themeaning of the first letter, “B”. It stands for “Biology” which is the study of living things. The “E” stands for electronics. Of course, a robot is a thingy made out of electronic components. BEAM tells us that a robot should use electronic components to make it behave in some ways like an insect or other living things. Nobody likes an ugly robot! The robots that we build should look nice, isn’tthat what we want? Yes!!! So the “A” in BEAM stands for aesthetics. Whoa!! I can barely pronounce that! How was that again and what does that mean? No problem! Today we all learn a new word: Aesthetics – as-the-tics – “The study and philosophy of the quality and nature of sensory responses related to, but not limited by, the concept of beauty.” (Found on various sites by Googling “aesthetics”) Ok,that did not help; can you repeat that in English? Sure! It simply means having the ability to look nice. Is that something we want for our robots? Well, BEAM wants that too! Now we just need a definition for the last letter, “M”. This stands for mechanics. A robot needs electronics to have it do something, but without a motor, what exactly is it supposed to do? Mechanics describes the motors,...