Autonomous ARDUINO-based robot with remote control. Robot Circling and avoiding obstacles

IR sensor obstacles for robots-machines YL-63 (FC-51)
Smart Car Obstacle Avoidance Sensor Module Infrared Tube Module Reflective PhotoElectric Sensor

The contactless sensor YL-63 detects objects in the range of distances almost from zero and to the established limit without entering them into direct contact. Different manufacturers are assigned different names to the same device. Some refers to the name sensor by the name YL-63 Other FC-51. The sensor is designed for use when information is not required to the object to the object, but only about its availability or absence. Limit reception depends on the setting. The YL-63 sensor has a discrete output. This is an optical sensor registering an increase in the intensity of reflected infrared (IR) radiation in the controlled space. The change in the reflected radiation occurs due to moving parts of the mechanisms or the movement of the surrounding items. YL-63 can be placed on a moving object to determine the situation in the surrounding space. It is used to detect the obstacle when driving wheel and tracked automata. The sensor can be part of a visual manual for students in the field of control and automation systems.
The device contains a source of IR radiation and a photodetector. Radiation is reflected from the obstacle and is recorded by the photodetector. It transmits a signal to the LM393 comparator, which is configured to trigger at a certain illumination level of the photodetector. The comparator generates a signal at the output of a low or high logical sensor of the YL-63 sensor.

The Optical Sensor YL-63 refers to the diffusion class. The name of the sensor group arose due to the underlying operation of the radiation reflection sensor on the sets of directions - diffusion of emissions by reflective surface.
The operation of the device is to determine the illumination of the photodetector. Since YL-63 fixes the reflected radiation, then the measurement error occurs, caused by various reflectivity of the surfaces of objects made from a variety of materials.

Distance coefficients for reflection from various materials.

White matte paper	1
Cotton fabric	0,6
Gray polyvinyl chloride	0,57
Wood
Few colored	0,73
Unproinited	0,4
Plastic
white	0,7
the black	0.22
Black rubber	0,2-0,15
Matte aluminum	1,2
Stainless polished steel	2,3

Various reflection and absorption of radiation of various materials are used to work the tachometer perceiving node. Suppose we have. It is required to know the number of revolutions per minute of the engine shaft. We will rescue YL-63. It is enough to glue a fragment of white paper to the flywheel, send the beam of the sensor to the flywheel and get a tachometer perceive knot.
To reduce the consequences of various interference, the processing microcontroller accumulates data from the sensor in a short period of time and averaging is performed. The YL-63 sensor can operate in devices that do not have MK.

Parameters

Power supply 3.3-5 V
Remote detection to reflective white matte plane 0.02-0.3 m
35 ° detection angle
Dimensions 43 x 16 x 7 mm

Contacts

Obstacle sensor YL-63 It also FC-51 has a plug of connectors from three contacts:
VCC - nutrition,
GND - shared wire,
Out - exit.

Indicators

There are two indicators on the module board. Glow green reports power on. The red LED glows if an object is located in the detection zone.

Setting distance of the response

The device setting facilitates the operation of the detection indicator. This allows you to configure the YL-63 in the same FC-51 for triggering in real conditions. The sensitivity sensitivity setting is performed using a variable resistor installed on the board. The obstacle is installed on the desired removal from the sensor photo devices. By turning the mobile contact of the variable resistor on the board of the YL-63 module, the operation of the response distance is performed, the red LED is turned on. Then check the remoteness of the response to the displacement of the reflective object. The setting is repeated at least three times.

Arduian signal processing programY.L-63.

The sensor signal is fed to contact 12 Arduino.

Void setup () (
Serial.begin (9600);
Pinmode (12, Input);
}
void loop () (
Serial.print ("Signaal:");
Serial.printLN (Digitalread (12));
Delay (500);
}

Sensors play in robotics one of the most important roles. With the help of various sensors, the robot feels the environment and can navigate it. By analogy with a living organism, these are sense authorities. Even the usual homemade robot cannot fully function without the simplest sensors. In this article, we will consider in detail all types of sensors that can be installed on the robot, and the usefulness of their use.

Tactile sensors

Tactile sensors give the robot to respond to contacts (forces) arising between it and other objects in the working area. Typically, these sensors are equipped with industrial manipulators, as well as medical robots. Machines equipped with tactile sensors effectively cope with assembly and control operations, that are, the functions requiring the subjects of work.

Working out modern humanoid robots, manufacturers equip them with these sensors to make cars even more "animated", capable of perceiving information about the world literally to the touch.

Optical sensors

When building a robot, just do not do without optical sensors. With the help of them, the device will "see" everything around. These sensors work with a photoresistor. Reflection sensor (emitter and receiver) allows you to determine white or black sections on the surface, which allows, for example, a wheel robot move along the drawn line or determine the proximity of the obstacle. The source of light often serves an infrared LED with a lens, and the detector is a photodiode or phototransistor.

Special attention deserves camcorders. In fact, this is the eyes of a robot. This type of sensors to today is widely used due to the growth of technologies in the field of image processing. As you understand, except for robots, applying camcorders are enough: the system of authorization, recognition of images, detection of motion in case of security activities, etc.

Sound sensors

These sensors serve for the safe movement of robots in space by measuring the distance to the obstacle from several centimeters to several meters. These include a microphone (allows you to fix sound, voice and noise), rangefinders, which are sensors measuring the distance to the nearest objects and other ultrasound sensors. Ultrasound is particularly widely used in almost all branches of robotics.

The operation of the ultrasonic sensor is based on the principle of echolocation. This is how it works: the dynamic of the device makes up the pulse at a certain frequency and measures the time until it returns to the microphone. Sound locators emit directed sound waves, which are reflected from objects, and some of this sound enters the sensor again. At the same time, the receipt time and the intensity of such a return signal bear information about the distance to the nearest objects.

For autonomous underwater devices, underwater hydrolytators are predominantly used, and on Earth, sound locators are mainly used to prevent collisions only in the nearby surroundings, since these sensors are characterized by a limited range.

Other devices alternative to sound locators include radars, lasers and lidars. Instead of sound, in this type of rangefinders, a laser beam reflected from the obstacle is used. These sensors have gained wider use in the development of autonomous cars, as they allow the vehicle to more effectively cope with the road movement.

Position sensors

This type of sensors is mainly used in unmanned vehicles, industrial robots, as well as devices requiring self-balancing. The position sensors include GPS (Global Positioning System), landmarks (play the role of the lighthouse), gyroscopes (definition of rotation angle) and accelerometers. GPS is a satellite navigation system that measures the distance, time and determining the location of the robot in space. GPS allows unmanned ground, air and water vehicles to find its own route and easily move from one point to another.

Gyroscopes in robotics also a common thing. They are responsible for balancing and stabilizing any device. But due to the fact that this item is relatively inexpensive, it can be installed in any homemade robot.

Accelerometer is a sensor that allows the robot to measure the acceleration of the body under the action of external forces. This device is similar to a massive body capable of moving along some axis and connected to the body of the device with springs. If such an instrument to push to the right, then the cargo will shift along the guide to the left from the center of the axis.

Sensors inclination

These sensors are used in robots, where you need to control the tilt, to maintain equilibrium and to avoid the coup of the device on the uneven surface. There are both with analog and digital interfaces.

Infrared sensors

The most affordable and simple type of sensors that are used in robots to determine the approximation. The infrared sensor independently sends infrared waves and, catching the reflected signal, determines the presence of an obstacle.

In the "Lighthouse" mode, this sensor sends permanent signals by which the robot can determine the approximate direction and distance of the beacon. This allows you to program the robot so that it always follows in the direction of this lighthouse. The low cost of this sensor allows you to install it almost on all homemade robots, and thus equip them with the ability to leave obstacles.

Temperature sensors

Temperature sensor is another useful device that is often used in modern devices. It serves to automatically measure the temperature in various environments. As in computers, in robots, the device is used to monitor the temperature of the processor and its timely cooling.

We looked at all major sensors that are used in robotics and allow the robot to be more agile, maneuverable and productive.

Unlike a person, robots are not limited to vision, hearing, touch, smelling and taste. Robot sensors are different types. First of all, robots use various electromechanical sensors to explore and understand the world around them and themselves.

Playing the senses of the living being at the moment is very difficult. Because of this, researchers and developers resort to alternatives to biological feelings.

What people can feel, but can not feel robots?

With the help of cameras, robots can "see", but have difficulty with understanding what they see. The robot can get an image from millions of pixels from the camera. But without complicated programming, he will not know that any of these points is denoted.

Distance sensors indicate the distance to the object, but it is necessary that the robot does not crash into an obstacle or object. Researchers and companies are experimenting with various approaches to robots sensors. Additionally, the sensors are developed, which allows the robot not only to "see" but "understand" what he sees.

This may take a long time before it can distinguish objects located in front of it on the table. Especially if they are located not as in the database of objects.

Robots are very poorly distinguished by the taste or smell.

A person can tell you, "it is the taste of sweet" or "it smells badly", while the robot needs to analyze the chemical composition. Then you need to look for substances in the database to determine that a person has a taste as "sweet" or on the smell as "bad."

Such robot sensors as flavor sensors and smell have been developed little. First of all, because there was no big demand for a robot, which can distinguish the taste or smell.

People have many nervous endings on all their skin, and we know when we touched someone to any subject or something touched us. Robots are equipped with buttons or simple contacts placed in strategically important places. For example, on the front bumper to determine if it comes into contact with the object.

Robots of the "Pets" type can have contacts or a group of sensors located on the head, legs or back, but if you try to touch the zone where there is no sensor, the robot will not understand what it concerned, and will not react. Since research in the field of humanoid robots continues, possibly such robots sensors as "electromechanical skin" will develop.

What can robots feel, but people can not feel?

The robot cannot tell you a pleasant tool or smell substance. Although the stages of the chemical analysis may give it much more information than a normal person can know about its properties. If the robot is equipped with carbon monoxide sensor, then it will be able to detect carbon monoxide.

This will increase safety as the carbon monoxide does not have color and smell for humans. The robot will also be able to tell you the level of the pH of the substance. Therefore, it can determine, it is acidic or alkaline, and much, much more.

People use a pair of eye to get visual information, although many people cannot determine exactly the distance to the object. A person can tell you that before the tree is about 20 meters. At the same time, the robot equipped with distance sensors can tell you that before the tree is 21.1 meters.

In addition, robots can give accurate values \u200b\u200bof various environmental factors, which people do not know or are not able to perceive.

For example, a robot can tell you what is its exact angular or linear acceleration. Although most people most people most likely determine that it moves or turns.

A person can tell you on the basis of his experience that the subject is hot or cold, without touching him. While the thermal imager can provide 2D thermal image in front of it. Although the person has five major feelings, robot sensors can have a practically infinite amount of varieties.

What sensors are needed for your robot?

So, what types of sensors are available, and what sensors do you need your robot? You must first ask yourself, for what purposes you need a robot and what it should measure. Then below can be viewed which types of sensors for robots.

There is a high probability that you will not suit any of them listed below categories, so try to determine the basic elements of the robot and break the task to the components.

Sensors for robots are:

1. contact
2. distance
3. positioning
4. reactive
5. using rotation
6. other

Contact sensors.

- Button / Contact Switch.

Switches, buttons and contact sensors are used to detect physical contact between objects, and not limited to people pressed by the buttons.

The robot bumper can be equipped with a touch sensor or button. Additionally, the "mustache" (as well as in the animal) can be used to detect an object at different distances.

• Benefits: Very low price, simplicity of integration, reliability.
• Disadvantages: The measurement distance is limited.

- Pressure measurement sensors

The button that offers one of the two possible readings (ON or OFF). As a result, the robot sensor produces an output signal proportional to it attached to it.

• Benefits: Allows you to measure how much power is applied.
• Disadvantages: May be inaccurate and more difficult to use than simple switches.

Remote sensors

- Ultrasound sensors

Sensors that use ultrasonic signals to measure the time between sending the signal and the return of its echo signal are called ultrasound. Robot sensors in this case are based on the study of volatile mice, dolphins and other animals.

Ultrasonic range finders can measure distance range, but used, in particular, in air and depend on the reflectivity of various materials.

• Benefits: Measuring the average range (several meters).
• Disadvantages: Surface and environmental factors may affect the testimony.

- Infrared sensors

Infrared range can also be used to measure distance. Some infrared sensors measure one particular distance, while others provide an output signal proportional to the distance to the object.

• Benefits: Low cost, fairly reliable and accurate.
• Disadvantages: A wider range than ultrasonic sensors.

- Laser.

Lasers are used when high accuracy is required, or a large distance to the object, or when both factors are present. Scanning laser rangefinders use spin lasers (ultra-free lasers) for two-dimensional scanning distance to objects.

• Benefits: Very accurate with a very large range.
• Disadvantages: Much more expensive than ordinary infrared or ultrasound sensors.

- Encoders

Optical encoders often use a pair of LED photodiode. A disc with holes are installed on the shaft, through which the signal from the LED falls onto the photodiode and the number of pulses is read.

A certain amount of holes corresponds to the full corner traveled by the wheel. Knowing the radius of the wheel, you can determine the total distance traveled by this wheel. Two encoders give you a relative distance in two dimensions.

• Benefits: If there is no slip, then high measurement accuracy. It is often installed on the rear shaft of the engine.
• Disadvantages: Additional programming requires more accurate optical encoders can cost expensive.

- linear potentiometer

The linear potentiometer is able to measure the absolute position of the object.

• Benefits: Accurately measures the absolute position.
• Disadvantages: Small range.

- Sensors of stretching and bending

The stretch sensor consists of a material, the resistance of which changes depending on how much it is stretched. The bend sensor is usually a sandwich from materials, where the resistance of one of the layers varies depending on how long it is bent.

They can be used to determine a small angle or turn, for example, how many fingers were bent.

• Benefits: It is useful when the axis of rotation is internal or inaccessible.
• Disadvantages: Small accuracy and possibility of measuring only small angles.

- stereocamera

Like human eyes, two cameras, located at a distance from each other, can provide information about the depth (stereo waiting). Robots equipped with cameras may be one of the most capable and complex robots.

The camera, in combination with the correct software, can provide good color recognition and objects.

Advantages: The ability to provide detailed information and good feedback.

Disadvantages: Complexity in programming and using information.

Positioning sensors

- Localization indoors (navigation in the room)

The internal localization system can use several beacons for triangulation (determining the relative position of the points on the surface) of the position of the robot position, while others use the chamber and landmarks.

• Benefits: Great for absolute positioning
• Disadvantages: It requires complex programming and use of markers.

- GPS.

GPS uses signals from several satellites rotating around the planet to determine their geographic coordinates.

GPS devices can provide geographic positioning with an accuracy of 5 meters, while more complex systems that include data processing and error correction, thanks to the use of other GPS units or go, may have accuracy of up to several centimeters.

• Benefits: Does not require markers or other links.
• Disadvantages: Can only work in the open space.

Sensors of rotation

- Potentiometer

The rotary potentiometer is, in fact, the voltage divider and provides analog voltage corresponding to the angle of rotation of the handle.

• Benefits: Easy to use, inexpensive, fairly accurate, provides absolute readings.
• Disadvantages: Most of them are limited to 300 degrees of rotation.

- Gyroscope

The electronic gyroscope measures the speed of the angular acceleration and supplies the corresponding signal (analog voltage signal, a serial communication channel, with I2C, etc.). Piezoplastins are used in the electronic gyroscope.

• Benefits: The lack of "mechanical" components.
• Disadvantages: The sensor is always exposed to angular acceleration, while the microcontroller can always receive a continuous input signal, that is, the values \u200b\u200bare lost, which leads to the "Draif" values

- Encoders

Optical encoders use mini-infrared transmitter / receiver pairs. The number of tears of the infrared beam corresponds to the full corner traveled by the wheel.

The mechanical encoder uses a very thinly processed disk with a sufficient number of holes to read certain angles. Therefore, mechanical sensors can be used both for absolute and relative rotation.

• Benefits: accuracy.
• Disadvantages: In optical encoders, the angle of rotation is relative (not absolute) from the initial position.

Robot sensors reacting to environmental conditions

- Light sensor

The light sensor can be used to measure the intensity of the light source, whether natural or artificial. Usually its resistance is proportional to the intensity of light.

• Benefits: Usually very inexpensive and very useful.
• Disadvantages: Could not distinguish the source or type of light.

- Sound sensor

Sound sensor is, in fact, a microphone that returns the voltage proportional to the level of ambient noise. More complex boards can use microphone data for speech recognition.

• Benefits: Cheap and reliable sensor.
• Disadvantages: In order to decipher important information requires complex software.

- Temperature sensors

Temperature sensors can be used to measure the ambient temperature or in difficult conditions, for example, in heating elements, furnaces, etc.

• Benefits: Can be highly.
• Disadvantages: More complex and accurate sensors may be more complex to use.

- thermal imaging camera

The thermal imaging sensor (camera) of the infrared or thermal image allows you to get a complete 2D thermal image of everything that is located in front of the thermal imager camera. Thus, it is possible to determine the temperature of the object.

• Benefits: It is possible to measure the thermal activity of objects selectively at a distance.
• Disadvantages: high price

- humidity measurement sensors

Humidity sensors determine the percentage of water in the air and are often connected to temperature sensors.

- barometric pressure sensor

Pressure sensor (which can also be a barometric sensor) can be used to measure atmospheric pressure. Therefore, it can give an idea of \u200b\u200bthe height of the CAP (unmanned aerial vehicle).

- Gas sensors

Gas sensors are used to determine the presence and concentration of various gases. However, they only need specialized robotic complexes.

• Benefits: These are the only robot sensors that can be used to accurately detect the gas detection.
• Disadvantages: Cheap sensors can give false responses or somewhat inaccurate and therefore should not be used for critical tasks.

- Magnetometers

Magnetometers can be used to detect magnets and magnetic fields. Can also determine polarity.

• Benefits: Helps to detect ferromagnetic metals.
• Disadvantages: In some cases, sensors may be damaged by strong magnets.

Sensors using rotation

- compass

A digital compass can use the Earth's magnetic field to determine its orientation relative to magnetic poles. The slope of the compass is compensated and takes into account the fact that the robot cannot move strictly horizontally.

• Benefits: Provides absolute navigation.
• Disadvantages: Higher accuracy increases the price.

- Gyroscope

Electronic gyroscopes are able to determine the angle of inclination on one or more axes. Mechanical tilt sensors, as a rule, determine the slope of the robot with mercury in glass capsules or balls.

• Benefits: Electronic gyroscopes have higher accuracy than mechanical.
• Disadvantages: Higher cost.

- Accelerometers

Accelerometers measure linear acceleration. This allows you to measure gravitational acceleration or any other acceleration that is experiencing a robot.

It can be a good option for an approximate distance estimate if your robot cannot use the environment to clarify the coordinates.

Accelerometers can measure acceleration along one, two or three axes. The three-axis accelerometer allows you to measure all the angles of the sensor inclination in space.

• Benefits: They do not require any external references or markers for functioning, and can provide an absolute orientation with respect to the Earth's gravitational field or determine the relative orientation.
• Disadvantages: They only approximately evaluate the distance traveled and cannot accurately determine it.

- IIB

The inertial measuring unit combines a multi-axis accelerometer with a multi-axis gyroscope and sometimes a multi-axis magnetometer in order to more accurately measure the roll. The robot sensors are quite complex.

• Benefits: This is a very reliable measurement method without using external links (except for the magnetic field of the Earth)
• Disadvantages: It can be very expensive and difficult to use.

Other

Current and voltage sensors measure the current and / or voltage of a particular electrical circuit. It can be very useful for determining how much your robot can work (measure the battery voltage) or if your motors work too much (current measurements).

• Benefits: They do exactly what they are intended.
• Disadvantages: Can make changes to the measured voltage or current. Sometimes it is required to change the measured electrical circuit.

- Magnetic sensors

Magnetic sensors and magnetometers are able to detect magnetic objects and may require contact with an object, or must be relatively close to the object.

Such robot sensors can be used on an autonomous lawn mower for detecting a wire based on a lawn or to search for hidden wiring in the apartment.

• Benefits: as a rule, inexpensive
• Disadvantages: As a rule, should be placed relative to the object, and unfortunately, non-magnetic metals cannot detect.

- Vibration sensors

Vibration sensors are designed to detect an object vibration using piezoelectric or other technologies.

- RFID technology

RFID technology is a wireless data exchange technology by means of a radio signal between an electronic label, which is placed on an object and a special radio electronic device that reads the tag signal.

Radio-frequency identification devices can be used both active (with power) and passive (without meals) RFID labels usually having a size and shape of a credit card, a small flat disk or addition to keychain (other forms are also possible).

When the RFID label is at a certain distance from RFID reader, a signal is created with the tag identifier.

• Benefits: RFID tags usually have a very low cost and can be determined individually.
• Disadvantages: It is useless for measuring the distance, except when the label is within the range.

Practical part

A typical example demonstrating the autonomous work of the robot is a robot based on the LEGO EV3 set for a line of line with one or two color sensors. In this case, the robot sensors define the brightness of the reflected light.