The raspberry pi is a credit card size single board computer developed in the United Kingdom by the raspberry pi foundation. By using this, the foundation can develop the teaching of basic computer science in the schools. The price of the raspberry pi board is very low and it is portable. Mostly the raspberry pi is used in the mobile phones and there is a huge increase in the mobile technologies. Maximum percentage, i.e is 98% of the mobile phones were using the ARM technology. The raspberry pi is used in the computers like video games, WordPress, and spreadsheet and also in the HD videos.
The Stepper motor is a brushless motor and the total number of steps are divided into steps. There are many applications for the stepper motor in the field of robotics and Mechatronics. The angle of the step is called as the stepper angle and there are two types of stepper motors, they are discussed in the article. The most common used stepper motor in the electronic hobbyists is the unipolar stepper motor. In this article, we have discussed briefly the interfacing stepper motor with the 8051 microcontroller. In this, the integrated circuit is AT89C51 which is from the microcontroller family.
What is a Stepper Motor?
A stepper motor is a brushless DC electric motor. It divides the full rotation into the equal no. of steps. Without any feedback sensor the position of the motor is moved and hold on one of these steps. The applications of motors are in respect to the torque and speed. The switched reluctance motors are large stepping motors with the help of the reduced pole count and they are generally closed loop. Stepper motors are also known as the step motor or stepping motors.
Different Types of Stepper Motors
The stepper motors are mainly divided into three types which are following
- Permanent magnet stepper
- Hybrid synchronous stepper
- Variable reluctance stepper
Two Phase Stepper Motor
The two-phase stepper motor has two basic winding arrangements with the electromagnetic coil are unipolar and bipolar.
Unipolar Stepper Motor
From the word of unipolar the “uni” means the current flow in one direction and this motor has two winding per phase, for each direction of the magnetic field. The following diagram shows the unipolar stepper motor.
The unipolar stepper motors are used in three modes of operations which are wave drive, full drive, and a half drive. The description of each drive is described below and it has its own advantages and disadvantages thus we can choose the required drive according to the application.
In the wave drive mode, there is only once electromagnetic is eager at a time. The generated force will be less when it is compared with the full drive in which the electromagnets are eager at the time and however the power consumption is important the torque. The wave drives are used rarely and the sequence of the wave drive stepping is following
In the full drive modes, there are two electromagnets are energized at one time, hence the torque generated is more when it is compared with the wave drive. The power consumption of full drive is higher than the other modes. The sequence of full drive stepper motor is shown in the following table.
The half drive is a combination of both drives which are wave drive and full drive. In the half drive mode, there is one and two electromagnets are energized. The half drive mode is used commonly to increase the angular resolution of the motor except the force will be less around the 70% at the half step position. When we use the half drives we can observe the angular resolution double. The sequence of the half drive stepping is shown in the following table.
Bipolar Stepper Motor
The bipolar stepper motor has a single winding per phase. From the word of bipolar the Bi means the current in the winding to reverse a magnetic pole, thus the driving circuit is complicated, typically with an H-bridge arrangement. The following diagram shows the bipolar stepper motor.
Stepper Motor Working
The working principle of the stepper motor is electromagnetic. The construction of the stepper motor is shown in the following figure. It consists of the rotor which is a permanent magnet and a stator with electromagnets. Currently, if we give power supply to the stator’s winding there will be a development of the magnetic field in the stator. With the help of the permanent magnet, the rotor of the motor is made. This is the basic working principle of the stepper motor.
Circuit Diagram of Stepper Motor
The following circuit diagram shows the four-stage stepper motor circuit and it is similar to the two-stage stepper motor. By observing the circuit diagram the reset pin is connected to the transistor Q2 and opened transistors are Q2, Q3 pins are connected to the other two transistors to generate the four pulses driving and to run the four stage stepper motor. Therefore, it is clear that we can make up to ten stage stepper motor. The diodes are connected to the collector terminal of the NPN transistor and the diodes are used to protect the transistors from the inductance spiking of the stepper motor. If the diodes are not placed there may be a risk to glow the transistors.
The diodes are connected to the collector terminal of the NPN transistor and the diodes are used to protect the transistors from the inductance spiking of the stepper motor. If the diodes are not placed there may be a risk to glow the transistors.
Interfacing Stepper Motor with the 8051
The components of stepper motor interfacing with the 8051 microcontrollers are an AT89C51 microcontroller, ULN2003A motor, resistor, capacitor, Crystal oscillator. The AT89C51 is a low power, high performance, 8bit COMS and it is from the 8051 microcontroller family. The microcontroller has 32 programmable I/O lines and it also has the 4K bytes of flash programmable and erasable memory. The crystal oscillator is connected externally to the 18 and 19 pins of the microcontroller. The stepper motor is connected to the port2 of the microcontroller with the help of the driver IC.
The ULN2003A is used to force the current of the stepper motor and it requires more than the 60mA of current. It is a current driver integrated circuit and it consists of the seven pairs of Darlington arrays with the common emitter. The total no. of IC pins are 16 in which 7 pins are input pins, other 7 pins are out pins and remaining two pins are connected to the ground and Vcc. The first four pins of ULN2003A are connected to the microcontroller and the output pins are connected to the stepper motor.
The stepper motor consists of 6 pins in this the two pins are connected to the power supply with 12V and remaining four pins are connected to the output of the stepper motor. By the given step angle the stepper motor will rotate, each rotation of step has a fraction of the full cycle and it depends on the mechanical parts and the driving method.
The stepper motor has the stator and rotor. The rotors have the stable magnet and the stator has the coil. The basic structure of a this motor has the 4 coils with the 90 degrees rotation and the four coils are in the cyclic order. There are different methods like full drive, half drive and wave drive is described starting with the article.
Advantages of the Stepper Motor
- The consumption of power is less
- The stepper motor requires low operating voltage
Applications of the Stepper Motor
- The circuit of the stepper motor is used in the robotic applications.
- It is also used in the mechanical applications. The stepper motors are also used in the disk drives, matrix printers and etc.,
This article describes the interfacing stepper motor with the 8051 microcontroller. I hope by reading this article you have got some basic knowledge about the stepper motor interfacing with the microcontroller. If have any queries about this article or about the interfacing microcontroller with the liquid crystal diode projects, please feel free to comment in the below section. Here is the question for you, What are the functions of the stepper motor?
In earlier, the most important and critical component used in an electronic device is a vacuum tube, used to control the flow of an electrical current. Vacuum tubes are bulky and need high power consumption, yield lower efficiency, higher operating voltages and also used electron materials which emit electrons for operation. So, that ended up as heat, which reduced the life of the tube itself. To overcome these complications, Walter Brattain, William Shockley and John Bardeen were developed a transistor at “Bell Labs” in the year of 1947. The transistor was a much smarter solution to overcome several of the essential limitations of vacuum tubes. This article gives an overview of transistor construction, types, applications,etc.
The Basic requirement of safety can be conquered by designing several door locks for security like electrical locks and mechanical locks. The designing of these door locks can be designed with one or multiple keys, but for securing a big area we need various locks. Normally, old-style locks are weighty and that are not solid as they can harm simply by using some gears. Electronic locks are superior over mechanical locks, to resolve the problems of security that are allied with the mechanical locks. Nowadays, every device uses digital technology. For a sample, door lock system using digital technology, recognition of digital device using a token, automatic door closing and opening, RFID door lock systems, etc. These kinds of systems are used for movement controlling of a door without using a key.
The resistor is a passive two terminal electrical components, that are used in most of the circuits. The resistors act as the lower voltage levels within the circuit and it is also used for reducing the current. The high power resistors can drive may watts of electrical power like heat. It is used for the motor controls in power distribution system. By using the temperature, time, and operating voltage can change the resistance of a fixed resistance. In the circuit elements the variable resistors are used in the form of light, sensing device to heat, chemical activity, and force. In the electrical networks and in electrical circuits the resistor is the common components. The different types of resistors are present everywhere in the electronic equipment and in the integrated circuits the resistors are implemented. If the practical resistors are discrete components, then it collects different types of components. The resistor of electrical function is specified by the resistance. The manufacture of resistors has a range of more than the nine orders of magnitude. By using the tolerance the value of the resistor is indicated.
What is a Resistor?
The resistor is a component, designed to find the known values of resistance. The resistors are also known as the passive components. The resistors are used for reducing the current in the circuits. The basic symbol of the resistor is shown in the below.
Different Types of Resistors
There are some different types of resistors in the electronic circuits. Depending upon the manufacture and contraction the resistance has different properties. It makes the difference in their applications. The resistors are available in different sizes and shapes in the market. The different types of resistor are discussed in the following section.
- Linear resistors.
- Non-linear resistors.
The resistor values are changed with the help of the temperature and applied voltages are called linear resistors. If the resistance of the current value is directly proportional to the applied voltage is called the linear resistance. The linear resistors are two different types of resistor which are the following.
- Fixed resistors
- Variable resistor
The name itself says that fixed resistor. So the values of the specific resistor cannot change in the fixed resistor. There are different types of the resistor which are in the following.
- Led arrangement
- Carbon composition
- Carbon Pile
- Carbon film
- Printed carbon resistor
- Thick and thin film
- Metal film
- Metal oxide film
- Wire wound
- Foil resistor
- Ammeter shunt
- Grid resistor
- Special verities
Carbon Composition Resistor
The carbon composition resistor is made from the mixer of granulated or graphite, insulation filter and a resin binder. The actual resistance of the resistor is determined by the ratio of the insulation material. The shape of the insulating binder is in the shape of roads and there are two metal caps at both the end of the roads. At both ends of the resistor it has two wire conductors for easy to connectivity in the circuit design. There are different colors which are printed on the resistor to find the value of it and the road is covered with the plastic coat.
- The composition resistor is used in the high energy pulses.
- It has a relatively small size.
- High voltage power supplies
- High power
This type of resistor is prepared with the stack of compressed disk between two metal plates which are in contact. These resistors are integrated in automatic voltage regulators and it controls the field current to maintain the constant voltage. The symbol of the carbon pile resistor is shown below.
- These are used in the speed control small controls small motor in home appliances.
- This type of resistors is available in carbon microphone.
- Carbon pile resistors are used in the adjustable load resistors if it requires like radio transmitter or automatic batteries.
The carbon film resistor is formed by cracking the hydrocarbon in a ceramic former and the temperature coefficient is from the -100 to -900 ppm/°C. The carbon film resistors are not using in the market because of the superior resistors are available in the market. These resistors are obtainable in small wattage levels. The symbol of the carbon film resistor is shown below.
The carbon film resistors are available in High plus stability.
Printed Carbon Resistor
The name itself says that the “printed” so this type of resistors are used on the printed circuit boards. These types of resistors are mostly common in hybrid PCB modules. The tolerance of these resistors is quite large and it is in the order of 30%. The symbol of this resistor is shown below.
- This type of resistors is used in the standard fiberglass in PCB’s.
- It has non critical pull up resistor.
Thick and Thin Film
In 1970s the thick film resistors are more popular and nowadays this type of resistors is in surface mount device. The thick film is 1000 times thicker than the thin films with resistive elements. The principal of both, the difference is in film applied to cylinder surface mountain device resistor.
The thin film resistors are prepared by a method of vacuum deposition and the resistive material are through the insulating substrate. The old process of making the printed circuit board is in film etched. The surface is covered with a photosensitive material and covered with a pattern film, irradiated with ultraviolet light and exposed to the sensitive coating. The manufacture of the thick film resistor is by using the screen and a stencil printing process.
- Thin film is usually used in precision applications.
- The thin film resistance features have a relatively high tolerance.
- The inductance and capacitors are generally low in thin film resistors.
- The thick film resistors are used in case of high tolerance.
- The thick film resistors are available in low price and it can handle low power.
- Thick film resistors have a wider range of resistors.
Metal Film Resistor
The construction of metal film resistors is similar like carbon film resistor. Instead of carbon there are a metal and metal is a mixture of nickel, chromium, metal glaze and metal oxides. The temperature coefficient of metal film resistor is very low and the value is +-2ppm/C. The symbol of metal film resistor is shown below.
- The tolerance of metal film resistor has good characteristics.
- The low voltage coefficient of this resistor has high linearity and low noise.
- In bridge circuit and active filter this film resistors are used.
Metal Oxide Film Resistors
The preparation of metal oxide film resistor is with the help of metal oxides and these resistors are fixed from the axial resistors. These resistors are confused with the metal oxide Caristors which are made with the help of zinc oxide, silicon carbide. The chemical deposition methods are produced with the help of metal oxide resistor. The pure metal gases like high temperature and low pressure involve in the deposition process.
- The application of metal oxide film resistors is mostly similar to the metal film resistor.
- The metal oxide film and metal film are the predominant resistors.
Wire Wound Resistors
This type of resistors is made up of the insulating the core to a resistive wire. The resistive wire is tungsten, manganese, nickel is allowed. These resistors are very costly and sensitive to test. This resistor is available in the range of 2 watt to 100 watt resistors. The wire wound resistors of Ohmic values are from the 1 ohm to 200l ohm.
- It has high security
- Accurate measurement and balance current control is required.
There are different types of variable resistors are following
- Adjustable resistor
- Resistance and decade boxes
- Special devices.
The adjustable resistors are also known as a rheostat. These resistors are two or three terminal device and used for the current limiting purpose through the manual operations. The accessible range of these resistors is from 3 to 200 watts. The power rating is between the 5 to 50 watts.
- It is a power control device.
- Speed of motors.
The potentiometers resistor will have an additional screw and it has a better efficiency of operation. The potentiometer resistors are also known as trimmers. By changing the position of the screw by rotating through small screw driver then the value of resistor can be changed. These resistors are made of carbon composition, carbon film, and wire materials. The range of this resistor is from 50 ohms to 5mega ohm.
- These are used in wide range of industries.
- It can be used in control input and position measurement.
The lead arrangements are from the through hole technology. The component of through –hole will have the leads. The body of leads is leaving axially the first one is in a line parallel with the past and having longest axis. The other one is leaving the body in radically. The other component is surface mount technology. In earlier days the through hole technologies are totally replaced with the point to point construction.
Thus, this is all about the different types of resistors and its application.We hope that by reading this article you have got a better understanding of the concept of different types of resistors and its applications. If you have any queries regarding this article or to implement electrical and electronic projects, please comment in the below section. Here is a question for you, what is the function of the Resistor?