Arduino is a tool for making computers that can sense and control the physical world through your computer. It is a development platform open-source physical computing, based on a simple microcontroller board and a development environment for creating software (programs) for the board.

Arduino can use to create interactive objects, reading data from a variety of switches and sensors and control many types of lights, motors and other physical actuators. Arduino projects can be stand alone or communicate with a program (software) running on your computer (eg Flash, Processing, MaxMSP). Board can be mounted alone or buy a ready to use software development and you can download it for free. The Arduino programming language is an implementation of Wiring, a similar physical computing platform, which in turn is based on Processing, multimedia programming environment.

Why should Arduino?
There are many other microcontrollers and microcontroller platforms available for physical computing. Parallax Basic Stamp, BX-24 from Netmedia, Phidgets, MIT Handyboard, and many others offer similar functionality. All these tools organize the complicated work of programming a microcontroller-friendly packages. Arduino can simplify the work with a microcontroller, offering several advantages over other systems for teacher, student and amateur. Here are some advantages of Arduino:

• Affordable – The Arduino boards are more affordable compared to other microcontroller platforms. The most expensive version of an The Arduino module can be mounted by hand, and even mounted and costs much less than 60 €
• Multi-Platform – The The Arduino software runs on Windows operating systems, Macintosh OSX and Linux. Most environments for microcontrollers are limited to Windows.
• The programming environment simple - Arduino is easy to use  programming environment for beginners and flexible enough for advanced users. Teacher thinking is based on the Arduino programming environment Procesing with students to learn to program in this environment will feel familiar with the Arduino development environment.
• Software upgradeable and open-source - The Arduino software is published under a free license and ready to be extended by experienced programmers. The language can be extended through C + + libraries, and if you are interested in learning more about the technical details, you can jump into the programming language C in which AVR is based. Similarly can be added directly in AVR C code in your programs if you wish.
• Scalable hardware and open source – Arduino is based on ATMEGA168 microcontrollers, ATMega328 and ATmega1280. The planes of the modules are published under Creative Commons license, so experienced circuit designers can make their own version of the module, expanding or optimizing. Even relatively inexperienced users can build the development board version to understand how it works and save some money.

Ports of the microcontroller – this I / O devices, allowing the microcontroller to send or receive data. The default port of the AVR microcontroller has eight bits of data that can be transmitted or received simultaneously. Each grade (or bit) corresponds to the output (pin) microcontroller. The legs of the microcontroller is also called pins. To designate ports use letters A, B, C, etc. Number of I / O ports varies depending on the model of the microcontroller. Any port of the microcontroller can be configured as input or output.

To do this, you should write to the corresponding port register DDRx desired value. In addition, as an input or output can be configured separately, any output (pin) port. In any case, if  you want to configure all port or a single output, you will need to work with DDRx register.

DDRx – direction data register. This register determines whether one or the other output port of input or output. If a discharge register DDRx contains a logical unit, the corresponding port pin is configured as an output, otherwise – as an input. The letter x in this case should designate a port name with which you work. Thus, for this will be port A register DDRA, Port B – DDRB register, etc.

Using the AVR GCC , written in the appropriate register a certain value can be one of the following methods.

For all the ports at once.

DDRD = 0xFF;

All D port pins are configured as outputs.

0xFF – hexadecimal representation of ff, where 0x is the prefix used to write hexadecimal numbers. In decimal representation this will be number 255, and in binary it would look like 11111111. That is, all bits of DDRD register will be written to logic one.

In AVR GCC to represent binary numbers use the prefix 0b. Thus, the number 11111111 to be presented in the program as 0b11111111. We can write the previous command for better readability.

DDRD = 0b11111111;

While such a record and is more obvious when you configure the ports made ​​to use the hex representation of numbers.

In order to configure all port pins as inputs D, you should write down all the bits in the register DDRD logical zeros.

DDRD = 0×00;

in DDRD register can be written and the other numbers.  For example:

DDRD = 0xb3;

0xb3 – hexadecimal representation of the number 179. In binary it would look like 10,110,011. That is part of the output port D is configured as outputs, and some – as inputs.

PD0 – 1 (out)
PD1 – 1 (out)
PD2 – 0 (input)
PD3 – 0 (input)
PD4 – 1 (out)
PD5 – 1 (output)
PD6 – 0 (input)
PD7 – 1 (out)

Each bit registers DDRx can be installed separately. For example, to configure a separate output PD2 as output, we need a corresponding bit in DDRD register to record 1. To do this, use the following construction.

DDRD | = 1 <<2;

1 <<2 – performs the shift left 2 bits, that is to the right added two zero bits, and turns 100, and the sign “|”, standing in front of the sign of the assignment “= “performs bitwise logical operation of addition.

With the addition of a logical 0 +0 = 0, 0 +1 = 1 1 +1 = 1 . The logical addition in another operation called OR

Thus, the bits stored in register DDRD, added to a binary 100, presented at the 8-bit microcontroller register as 00,000,100, and the result is written back to register DDRD.

To configure the output PD2 separately as an input, we need a corresponding bit in DDRD register write 0. To do this, use the following construction.

DDRD & = ~ (1 <<2);

In this case, the result of shifting units at two positions to the left is inverted by inverting the bit-operations, denoted by a ” ~ . ”

When we get the inversion instead of zeros, but instead of ones – are zero. This logical operation is also called the operation NOT.

Thus, when one bit inversion 00,000,100 11,111,011 we get. (For information about working with numbers in the microcontroller, see the sidebar below.)

The resulting number by performing a bitwise logical multiplication is multiplied by k number stored in the register DDRD, and the result is written into the register DDRD.

When the logical multiplication of 0 * 0 = 0, 0 * 1 = 0, 1 * 1 = 1 . The operation of logical multiplication operation is also called AND.

So we shifted to the left by two positions ones transformed with inversion at zero and multiplied by the corresponding bit which stored in register DDRD. When multiplied by zero, we get zero. Thus, the PD2 bit is zero.

However, despite the fact that many of the humanoid robot called human-or, in reality they are like us only vaguely. However small team of scientists achieved a breakthrough of the National Institute of Advanced Industrial Science and Technology (AIST) with his trademark wards robot HRP-4C, which already was very similar to human, or rather a pretty girl.

Balancing robot on two wheels is a little complicated in design realization for some people, this is partly true. Making such robots require accelerometers, gyroscopes and sophisticated software. But in fact, a simple balancing robot can even be built from Lego parts using a relatively simple sensors and a set of Lego Mindstorms. It’s like a Lego robot that was built in 2003, by Steve Hassenplug. Steve called it LegWay Lego robot and uses two optical proximity sensor EOPD (Electro Optical Proximity Detector) from HiTechnic. Lego robot device is easy to understand just by looking at the photo above. Two sensors mounted in such a way as to control the distance to the surface along which the robot moves. If the distance to the surface beneath the sensor is reduced or, conversely, increases, the robot produces the appropriate motion with the flattening of the engine. Steve Hassenplug Lego robot is able to balance, to walk in a line or circle on the ground.

A more stable structure of the proposed James Matthews in November 2004. He uses standard LEGO sensors that respond to reflected light, put them in front of and behind the robot. This design allows the robot Lego to create a more stable balance, but in order to run on the phone, you should use additional sensors. The code that controls the robot is very simple. James Mafius write with NQC, using BricxCC software environment. Maybe if you use this code you will need an individual sensor calibration.

# Define SENSOR_3_THRESHOLD 49
# Define SENSOR_1_THRESHOLD 45

Task main ()
{
/ / Setup

/ / Now balance!
until (false) {
if ( SENSOR_1 > = SENSOR_1_THRESHOLD) {
OnFwd ( OUT_A );
OnRev ( OUT_C ​​);
Wait (1);
}
if ( SENSOR_3 > = SENSOR_3_THRESHOLD) {
OnRev ( OUT_A );
OnFwd ( OUT_C ​​);
}
}
}

Balancing Lego robot can be constructed from a set of Mindstorms NXT. Philippe Hurbain proposed the construction of a robot using only one sensor. The robot called Philip NXTway .

To write a program used by NBC and BricxCC programming environment. Compiled program can be download here. To load a compiled program in the NXT using the download button on the panel in a standard programming environment, Lego Mindstorms NXT. In February 2007, Ryo Watanabe of Waseda University, who inspired design lego-robotics Hassenplug and Hurbain, has created a sophisticated version of the balancing robot using a gyro-sensor. Robot named NXTway-G.

Here are some examples of the type of BEAM robots :

Solaroller – a small robot on wheels that moves through the energy produced by solar batteries. The functioning of the robot consists of two phases: phase accumulation of energy in a capacitor and a phase when the capacitor is rapidly discharged into the electric motor. Depending on the design, solarroller on a single charge can travel from a few millimeters to a few steps.

Photovore – these are two solarroller’a connected together. The basis of such robots is Photovore response of phototropism, which causes them to move to the brightest source of light. The main sensors are photoelectric sensors such robots, to determine the direction of the light source. Often, robots equipped with tactile sensors to detect and circumvent obstacles encountered on the road. Mechanical scheme Photovore usually very simple: robots do not use gears and move directly on the axes of the two motors.

Walker – walking robot, referring to the most numerous class of BEAM-robots. The most common robots in this class have four legs driven by two motors. Number of legs and modes of transportation in walker’ov not limited. The electronic circuits are most commonly used neural circuits built on the oscillators. This is not a complete list of classes BEAM-robots that can be counted more than two dozen. There are also stationary robots.

Pummers, which accumulate energy during the day, which they use after dark to colorful lighting effects. Like nothing on earth.

Turbots , moving on curved “arms”, and many others.

Biology

Electronics – used to control the BEAM-robot. One feature of BEAM-style is a minimalist approach in the use of electronics, which allows you to create automatic graceful creations that mimic living creatures using only some parts of a solution. On again fairly simple schemes can achieve complex behavior and reactions to the world. Often neural chain can give much more adapted behavior than ten lines of code.

Aesthetics – means that the BEAM-robots should look good. “I’m an engineer, but even I appreciate the beautiful design” – says Tilden. The design must be “beautiful”, not only in terms of design, but also on their design decisions. In addition, if the design looks “clean”, it is more likely that it will work well and it seemed easier to test and debug than a confused and rebellious design. “Do it nicely and it will work better.”

Mechanics – is often the secret of good design BEAM-robot. Using the “clever” design, you can reduce the complexity of the rest of the robot (for example, reduce the number of actuators or sensors). Even the most simple design can be varied in behavior, if we apply the interesting mechanical solution.

Despite the fact that the acronym BEAM (Biology Electronics Aesthetics Mechanics) is well established and proposed by Tildenom in the BEAM-community there are a number of popular acronym with the word BEAM, such as these:

Building Evolution Anarchy Modularity
(Creating a Modular Evolution of Anarchy)

Biotechnology Ethnology Analogy Morphology
(Biotechnology Ethnology Analogy Morphology)

There is also every reason to believe and what is triple the acronym BEAM, that is just mean

Biology Electronics Aesthetics Mechanics
Building Evolution Anarchy Modularity
Biotechnology Ethnology Analogy Morphology

BEAM-robots, in contrast to conventional robots, based on digital technology and microprocessors are created by analog circuits. Instead of a discrete program of behavior of robots is given by the analog neural circuits capable of flexibly choose the way around obstacles and respond to the world.