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a Robot .pdf from Wiki


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This article starts you in the right direction to understanding some of the terminology connected with simple one and two motor solar-powered vehicles. As you will find out, they have the name BEAM and are the simplest yet most-functional designs to be produced. 
This article is intended to bring everyone together. There are links to hundreds of websites created by individual hobbyists, like yourself, and some of the fantastic photos on the sites have been reproduced to show you what has been designed. 

There are four electronic kits available in this section. They are "universal" kits and can be fitted to your own robot. 
The kits are:  Solar Engine
              Sun Eater 1A
              Sun Roller MkIII
              Robo Roller MkII

You will also need hardware items, wheels, motor(s), solar panel etc (if not included in the kit). 
Click HERE for details and comparisons between each kit.

Before we enter this wonderful world of "artificial life," let's go over the "frightening background" of robots and cover some of the terms used to describe these devices. 

Robots are not new. They have been portrayed in movies long before we had the ability to produce a "life-like" creature. The possibility of being invaded by Aliens, "Martians" or Robots fascinated movie producers in the early days and movie-goers were glued to their seats with the possibility of invasion by these robot-like creatures. 
The radio broadcast produced by Orsen Welles in the early 30's had such a devesting effect on the audience that a protocol for broadcasting came in soon after. 
The basis of his terrifying "stunt" was to produce a normal news program and then have a "live" incident where unknown creatures actually entered the studio and caused havoc. 
The terror and horror was played out by actors but in the early days of broadcasting the audience had never experienced a "trick" like this and the phone lines ran hot. People ran into the street in panic. It created so much chaos that similar broadcasts were banned from that day on. 
The word Robot comes from the word Robotnic - to work, however the word Robot and Automation was been introduced into the world with a lot a fear. 
Not long ago, the word automation struck absolute fear into almost the entire world of factory workers. 
With the advent of electronics, the transistor, and mechanics came some of the earliest attempts to produce devices that appeared to carry out the job of a factory worker. It was portrayed that the factory worker would soon become redundant. 
Although crude and almost non-functional, these robot-like inventions gave the impression that a simple program could be produced to make a robot perform almost any task currently carried out by a worker - especially a repetition operation. 
The immediate impression was for all jobs to be taken over by "machines." 
It was soon realised that a universal robot to do the simplest operation was not easy to produce and the fear gradually subsided. 
However a lot of dangerous and simple operations were converted to machine operation and this introduced the generally-unknown era called the Automation Revolution. 
This is not to be confused with the Industrial Revolution of the early 18th Century where machines were invented to carry out a task. These early machines were quite often of steel and wood construction and driven by a system of overhead pulleys and belts with a power plant (a steam engine) at one end of the factory. The machines were turning, cutting, weaving and sewing and produced shoes, clothing, cooking utensils, implements and the like. 
The Automation Revolution is much more recent and much more subdued. It was introduced much more quietly and covertly. 
Many of the old-style machines performed a single operation and required banks and rows of machines to complete a task. The inefficiency and cost of this method of production was soon realised and smart new machines were invented that allowed the raw material fed into one end and the finished product taken from the other. 
In most case a number of machinists were taken over by a single "new-invention" and due to the automatic nature of the operation, the output was more-than-doubled in the process! 
As you can see, the history of Robots and anything to do with automation has had a fearful introduction and it only the younger generation that looks on these devices with glee. Ask your grandparents and find out how they saw the possibility of robots taking over their livelihood.
Hopefully the era of trepidation has passed and we can now look upon this amazing world of "design-machines" with enthusiasm.
Undoubtedly, robotics is going to be the "science of assistance" in the future. Already we have robots carrying out dangerous tasks, tasks of assistance for the disabled and even research tasks where a small amount of intelligence is given to the robot and it has the capability of self-learning. 
The one thing that fascinates me with robotics is the combination of electronics with mechanics. 
I have a very strong interest in both areas and this is where a combination of talents can be expressed to its fullest. 
As you will find, the biggest difficulty with producing any type of device in this area is the mechanics. 
Electronic components are universal and readily obtainable. But the mechanical components are much more difficult to obtain. 
One of the solutions it to provide a kit and this will be answer to most of the projects we will be presenting. 
Don't think that robots are limited to a 3-wheeled "mice-like creature" that runs around the room in search of a light-source. This is only the start of a design. The knowledge gained by designing and combining electronics with mechanics can be expanded in all sorts of directions. 
It's only the advent of the web that has produced a whole network of enthusiasts and programmers for microcontrollers such as the PIC chip and maybe soon a network will be created for designers of electromechanical devices. 
This is needed due to the complex nature of the componentry. Mechanical items are very expensive when produced on a "one-off " basis but incredibly cheap when mass produced. 
This is the one factor that slows down inventiveness. 
What is needed is a pool of resources and a form of standardisation. 
This way such things as motors, gearboxes, actuators etc can be incorporated into new ideas at the lowest cost. 
It's an enormous task but it can be done. 
The way to do it to have "off-shoots" or clones of the currently-available robot kits and offer them as spares for expanding the kits. 
This way, working models can be produced cheaply. 
Another set of componentry can then be available for the full-scale design. This will obviously be larger, more rugged items.
Along these lines I have two pet inventions. 
One is a low-cost wheel chair and the other is a robot-arm that can be programmed to carry out a single operation. 
It is effectively a bench-top design where a conveyor belt passes a row of arms and such things as labelling, filling and sealing can be performed by the arms. 
They can then be easily re-programmed to pack a kits of components or add parts to a PC board. 
My other invention is a low-cost wheel chair. Mass production could bring these vehicles down to a few hundred dollars and at least make them travel in a straight line!
Again the power of the web will enable inventors to get together with manufacturers and produce a product that works and is much more affordable.
It will happen. It just takes time. The web is only new and is still sorting itself out. "Rings" are the first way to get people together and then we need a central administrator to get the financial side operational. 
So, if you think this topic is just for amusement, you haven't looked laterally. 
The potential is enormous and although I will be presenting some very interesting items from our own resources, there will also be a number of projects from other designers. There is a lot already on the web but it takes hours to "sort-through." I have done this "leg-work" for you and provided a number of links on everything I have presented.
In the main I have read the content of all the sites and created a "linear-approach" so the new reader can understand the technology of this field. 
The simplest robots fall into the BEAM classification and you will learn exactly what this work means and how to make your own models. 
Don't think of these things as a toy. They are really much more than a "powered vehicle." The electronics involved starts a simple level and becomes quite complex with the larger models. You can use this knowledge of circuity as a stepping-stone to other things in electro mechanics. 
Automation is everywhere and new designs are constantly in demand for everything from door openers to prosthetic actuators. Even if you don't consider yourself competent at designing something new, a re-design or improvement or cost-effective design could set you on your feet in the manufacturing world. 
This is an area for great inventiveness and I could go on for hours with ideas I have in the back of my mind. 
Simple things such as locks that bolt each door and window as soon as you leave the house,  over-bed cranes to lift disabled people to the bathroom, cars that lock themselves automatically when you are more than 2 metres away and unlock when you arrive. Car keys that tell you the direction of your car in a car-park! (it works on the increasing strength of the signal as you get closer to the car). 
These are all complex, expensive items, when made singly but in mass production, they will be economically viable. Look at the Ford motor car. Look what mass production did to the price. Cars have continued along these lines ever since. 
Almost everything hand-held has followed the same path. Now it's time for some of the larger items to see a price fall by becoming mass produced.
It's a "catch-22" situation. 
The price has to fall but to be able to offer a low price, it has to be mass produced. But to produce it in large quantities, the sales have to be high. 
So, where do you start?
Start HERE. 
Get your grounding with us and become an industrialist. 
You never know where a small robot will take you . .  .

Robotics has its own terms and terminology to describe the range of devices it incorporates. 
Robots are not simply called robots but  'bots. Then we have the coined name for a range of very simple designs: BEAM. It's best to let Eric Seale describe these, from his list in Solarbotics Encyclopaedia.  This is only a few terms from his library, but it's enough to get you started.

BEAM is a school of robotics, starting from simple reflexes, in a "bottoms-up" approach. The majority of BEAM robots are non-computerized (although simple CPUs can be used to drive them, in a "horse and rider" sort of way). Unlike many traditional processor-based robots, BEAM robots are cheap, simple, and can be built by a hobbyist with basic skills in a matter of hours. Because of this, BEAM is an excellent way of getting started in robotics, and of learning about electronics. BEAM is the brainchild of Mark W. Tilden who is currently working as a researcher at Los Alamos National Laboratory.

BEAM is an acronym for Biology, Electronics, Aesthetics, Mechanics:

Biology -- It's tough to beat 4 billion years of evolution; the world around us is a wonderful source of inspiration and education. Bear in mind, of course, that unlike Mother Nature, you also have the advantage of gears, motors, bearings, and good glues!

Electronics -- It goes without saying, but this is what we'll use to drive our creations. BEAM robotics, though, strives for rich behaviours from simple circuits. Here's the key: simple and understandable circuits, surprisingly complex in behaviour.

Aesthetics -- This just means your creations should look good. I'm an engineer, but even I appreciate a good-looking design. Besides, if a design looks "clean," it's more likely to work (and easier to test / debug) than a design that's tangled and unruly.

Mechanics -- This is the less-than-obvious secret of many successful BEAMbots -- with a clever mechanical design, you can reduce the complexity of the rest of your robot (reducing the number of motors and sensors, for example).

BEAM robotics basically starts from 3 philosophical tenets:

  • Use minimalist electronics
    This keeps complexity from "snowballing", and keeps costs down
  • Recycle & reuse components out of technoscrap
    This keeps things cheap, and avoids a lot of trips to parts stores; virtually all the parts required to make a BEAM robot can be found in broken electronics (ovens, walkman's, CD players, VCRs, pagers...).
  • Solar power your critter if possible
    While less powerful than even a small battery (and, up-front, more expensive), solar cells last for years; solar-powered BEAMbots don't require constant battery replacements or down-time for battery recharging.

While BEAM robots are often simple (consisting of a solar cell, motor, 2 transistors, and capacitor), robots as complicated as 8-jointed, 4-legged walking spiders have been built using the principles of BEAM.

A simple circuit, designed to gather energy from light, store the energy, and then release that energy in bursts to drive a motor, coil, or some other circuit. Solar engines can "trigger" (release their stored energy) based on a voltage, time, or charge-rate threshold.

At the heart of most solar-powered robots is a circuit called the solar engine (variously called Solar Engines, Solarengines, SEs; a.k.a relaxation oscillators). The purpose of a solar engine is to act like a power "savings account" -- a small trickle of incoming energy is saved up until a useable amount is stored. This stored energy is then released in a burst, in order to drive some useful (if only sporadic and incremental) work.

The solar engine has a number of advantages:

  • A solar-powered robot can be made to work in even low light levels.
  • Solar cell size is minimized
    • Saves money
    • Saves weight
    • Allows room for the solar cell to be ruggedized.
  • Four types of solar engines can be built:

    • Type 1 - voltage controlled trigger. This is by far the predominant form of solar engine, since they are "efficient enough" for most uses, and pretty simple to build.
    • Type 2 - time controlled trigger. These aren't terribly efficient, but are handy for 'bots that need activity at specific times.
    • Type 3 - charge curve differentiated (i.e., it triggers when the charge rate of the capacitor slows down). These are theoretically the most efficient, though type 3 designs are still in their infancy.
    • Nocturnal -- These solar engines charge up when it's light, and discharge (i.e., power a load) when it's dark.

    FLED (Flashing LED)
    Flashing LED; also, by extension, the name of a solar engine based on a flashing LED. A flashing LED is just an LED with a built-in microcircuit to cause it to flash periodically. Since the FLED draws current when it flashes, we can use FLEDs to drive a number of time-dependent circuits (via the fact that it periodically becomes conductive).

    Like other LEDs, FLEDs are (very slightly) light-sensitive, and so flash faster in brighter light. Note that some FLEDs need 3v minimum to work. They don't require current-limiting resistors when used up to 9v. They have a built-in resistor.

    A simple two-motor phototropic photovore. Movement either toward or away from the brightest available light source (a function of the 'bot's design) is accomplished by sporadic differential firing of two small motors.

    See the BEAM Bestiary model on photopoppers here

    Literally, a "light eater," this term properly describes all solar-powered BEAM robots. Note that this term is often inaccurately used to denote photopoppers and other phototropic BEAMbots. Bear in mind, though, that not all photovores are photopoppers, and not all photopoppers are photovores. In particular, photovores are not necessarily phototropic.

    Solarrollers are basically just simple solar powered drag racers. These are powered by a single solar engine, and have a single motor driving one or more wheels.
    More information on Solarrollers, including a gallery with links to existing creations of this type, is available on the BEAM Bestiary Solarroller pages.

    -tropic, -trope
    Goal seeking, "turning toward" (literally "turn / turning," but generally used to describe "turning toward," rather than "turning away from"). Many BEAM robots are 'tropes of one kind or another:

    Audiotropes seek out sound sources
    seek out light sources (these are the most common
                 form, as many BEAMbots are also photovores)
    seek out RF sources
    seek out heat sources

The simplest robot is a motor, battery and switch. Turn on the power and it moves until it hits something. 
This type of design doesn't hold much excitement, however it does provide a starting point for connecting a supply to a motor and watching the action.
Some of the toys of this type in "hobby shops" are very low cost and provide a motor,  housing (chassis) and gearbox.
This is one path for a design but is not the path we follow in this discussion.
The designs on the toy-market generally include a gearbox but this luxury is not available for the home constructor. Instead, the home-brew designs need to rely on the shaft of the motor making contact with the ground.
This provides very little grip and is generally just sufficient to move the project along a flat surface. If you want to follow the designs for the robots in the BEAM category, you will need to construct something like the one in the photo below. It consists of two motors, two sets of electronics and a solar-cell. This project is called


A simpler design uses a single motor. It is called SOLAROLLER:


Another 2-motor design is called PhotoPopper:


All these designs have one thing in common. The electronics consist of a Solar Engine Circuit for each motor. 
This circuit is designed to take the low current from a solar panel and charge an electrolytic. At a threshold voltage, the energy in the electrolytic is passed to the motor. Some designs need one set of components, others needs two. On the next page we describe the Solar Engine Circuit.

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