There are a number of standard microcontroller families which are used in various applications as per their competence and possibility to perform the preferred task, most common microcontrollers are 8051, AVR and PIC microcontroller. In the year 1996, AVR was developed by Atmel Corporation. The architecture of this microcontroller was developed by “Alf-Egil Bogen” and “Vegard Wollan”. The term AVR derives from its developers and stands for Alf-Egil Bogen Vegard Wollan RISC microcontroller, also known as “Advanced Virtual RISC”. The first microcontroller AT90S8515 was based on the AVR architecture, but the first microcontroller to hit the salable market was AT90S1200 in the year 1997. In this article, we will present you to this basic of microcontroller, and its applications.
Generally, we all known about shift register, combinational circuits and the other important element in the digital electronics is a counter. The counter circuits are used for counting purposes, and it is also used for measuring the frequency and time. The counter circuits are designed especially for synchronous sequential circuits. The state of the counter is equal to the count held in the circuit by the flip flops. The counters will calculate the number that how many times an event occurred. The counters are the crucial hardware components and they are also known as timers and these are the best examples of the flip flops. These are also used to design programmable timers.
What is a Counter Circuit?
Generally, the counter circuits are constructed by using a number of flip-flops which are connected in cascade. The manufacturing of counter circuits is separate integrated circuits and it is inbuilt in the part of larger integrated circuits. The counter circuits are widely used in the digital circuits. There are different types of counter circuits like synchronous counters, asynchronous counters, decade counters, ring counters, and Johnson counters.
Pin Configuration of AVR Atmega8 Microcontroller
The AVR Atmega8 Microcontroller consists of 28 pins and all the pins of the microcontroller will support two signals except 5 pins. From the 28-pins of microcontroller the port B pins are 9,10,14,15,16,17,18,19, the port C pins are 23,24,25,26,27,28, &1, and the port D pins are 2,3,4,5,6,11,12. The following image shows the pin configuration of the AVR Atmega8 microcontroller and description of each pin is described below.
Pin-1: RESET pin. If we apply low-level signals for a longer time than the minimum pulse length will produce the RESET pin
Pin-2 & 3: A serial communication in the USART
Pin-4 & 5: An external interrupt. From these two pins, one of the pins is active when an interrupt flag bit of the status register is set and the other pin will be active as long as the intruder condition succeeds.
Pin-9 & 10: An external oscillator pins as well as timer counter oscillators. The crystal oscillator is associated with the two pins directly. The pin-10 is used for lower frequency crystal oscillators or the crystal oscillators.
Pin-19: Used for the SPI-channel as a Master CLK o/p, slave CLK i/p.
Pin-18: A CLK I/P, slave CLK O/P.
Pin-17: Used for the SPI-channel as a Master data o/p, slave data i/p. When it is allowed by the master, it is used as an i/p when it is improved by the slave & bidirectional. This pin can also be utilised as an o/p compare with match o/p, which helps as an external o/p for the timer/counter.
Pin-16: Used as a timer or counter1 comparatively by ranging the PB2-pin as an o/p. It is also used as a slave choice i/p.
Pin-15: Used as an external o/p of the timer or counter compare match A.
Pin-23 to 28 is used as an ADC channel. Pin-27 is used as a serial interface CLK and pin-28 is used as a serial interface data.
Pin-12 &13: Analog Comparator Inputs.
Pin-6 & 11: Timer/counter sources.
Frequency Counter Circuit By Using ATmega16
The following circuit shows frequency counter circuit using the ATmega16 microcontroller. This frequency meter or counter is used to measure the frequency up to 4MHz because we are using an 8MHz clock for the ATmega16 microcontroller. The working operation of this circuit is to count the number of pulses of a signal in one second is simply the frequency counter circuit.
To count the pulses of a signal, we are using the timer1 of the ATmega16 and it will measure the frequency by using the normal mode. When we are starting the count pulses it makes a delay of one second, then we stop the timer and read it in the register which contains the number of pulses. If the timer1 is made an overflow then we are enabling the overflow interrupt of timer1 then we are going to count the number of overflows which are which are made by the timer1. The overflow means the timer1 has made 2^16 count. Therefore, by using the following equation the number of pulses in one second can be calculated.
Frequency = i*2^16 + TCNT1
From the above equation
It is used to calculate the number of overflows in one second. Reading the frequency meter is updated for every second.
Digital Stop Watch Using Atmega8 Microcontroller
The following schematic diagram shows the digital stopwatch using an Atmega8 microcontroller. The operational principle of this circuit is, in the starting stage the stopwatch is in the STOP condition and it is identified by through the blinking display. Generally, the counting stats from 00:00, if we press the START button then the count starts. If the watch is in the running condition then the display will not blink and the display will be on.
It will start counting and the mini seconds are displayed. By pressing the halt key the digital stopwatch is stopped, in the halt state the counting freezes and the display starts blinking. By pressing again START key the digital stopwatch starts from the resume counting. The RESET key is used to reset the clock and the clock starts from 00:00 i.e. 0 minute and 0 Sec.
Applications of Counters
- The counters are used widely in the flip-flops.
- It is used in the cricket stadiums to count the number of people entering & leaving the stadium or room or auditorium.
- The operations of microwave ovens and washing machines are by using the counters
- The counters are used in the digital electronic devices like the digital clock, analogue to digital converts, and digital triangular wave generators.
The information in this article is about simple counter circuits AVR Atmega8 microcontroller. I hope by reading this article you have gained some basic information on the counter circuits. If you have any queries about this article or about the implementation of electrical and electronic projects, please feel free to comment in the below section. Here is the question for you, what is the function of the counter circuit?
Nowadays, in several complex systems, there is a simple problem for car parking systems. There are various lanes of vehicle parking, So to park a car one has to search for the lanes. Moreover, there are a lot of labor men involved in this procedure for which there is lots of investment. To overcome this problem, here is a system which specifies the parking slot is vacant in any lane. This project includes IR transmitter, IR receiver in every lane and also a LED and LCD displays at the outside of the car parking gate. So the person entering into parking area can see the display board and can select which lane to enter so as to car parking.
In the year 1997, the electronic eye security system was found and base of processes in New Delhi. There are different organizations under these systems,such as electronic eye Pvt.Ltd, IIST (Indian institute of science and technology), electronic eye systems, and Mahamahi Exims. The electronic eye security system creates an entire collection of surveillance products and high-tech security. These Systems work on the integration of system and project execution at the customers place for numerous surveillance products.The electronic eye security systems which are available in the market are expensive, and programming is very problematic for a microcontroller based system. Here is a simple and inexpensive electronic eye security system that you can build easily.
Photo-sensing (LM393) based Electronic Eye Security System
The main goal of this project is to design an electronic security system based on a photo-sensing arrangement. It uses a double comparator LM393 that is extensively used in several profitable applications. Here, it is used to detect the input signal through a LDR (light-dependent resistor). The output of the comparator drives a relay and a buzzer. This concept is very beneficial as a burglar warning in public places such as banks, hotels jewelry stores, malls, and homes.
What is LM393?
The LM393 is a dual independent precision voltage comparator accomplished by single or split supply process. These devices are intended to let a common mode range-to-ground level with the only supply operation. Input offset voltage conditions as low as 2.0 mV make this device a superb collection of several applications in buyer automotive and industrial electronics. The features of LM393 include the following.
- Single supply ranges from 2.0 Vdc to 36 Vdc
- Split Supply Range: +/-1.0 Vdc to +/-18 Vdc
- Low Current Drain Independent of Supply Voltage: 0.4 mA
- Low i/p Bias Current is 25 nA
- Low i/p Offset Current: 5.0 nA
- Power Supply Voltage and differential i/p voltage range both are equal
- O/p voltage is compatible with ECL, DTL, MOS, TTL, and CMOS Logic Levels
- ESD locks on the i/ps
- ESD Locks on the i/ps increase the roughness of the device without disturbing performance
Circuit and Working of the Electronic Eye Security System
The circuit diagram of an electronic eye security system using LM393 is shown below. The following circuit is built with various electrical and electronic components like around 12V-0-12V, X1-(750mA secondary transformer), 1N4007 rectifier diodes (D1 through D3), LDR , C1 and C2 filter capacitors, 5V IC17805 voltage regulator, IC2 (dual comparator LM393), 12V PZ- (multi-tone high-gain buzzer), T1 transistor for driving PZ1, T2 transistor BC547 for driving 12V, relay (1C/O) for controlling a bulb (B1), and 10-kilo-ohm potentiometer VR1.
When the light drops on light dependent resistor (LDR1), its resistance extremely falls, which leads to activating an alarm to alert the user.The proposed system is appropriate for locking lockers, cash boxer, etc. This circuit is located in the locker or cash box in such a way that, when the robber opens it and uses a torch light to discover the valuables, light falls on light dependent resistor (LDR1), which performs as an electronic eye.
The signal o/p from the light dependent resistor (LDR1) is fed to IC2. The o/p from IC2 triggers the alarm when light falls on light dependent resistor during a robbery attempt.Similarly, bulb-B1 glows as a visual aware to prevent the burglary attempt.
If the reference voltage at pin-3 of IC2 is less than sensor voltage at pin -2 of IC2, o/p goes low routinely. This specifies that no light is dipping on the light dependent resistor. Low o/p of IC2 is fed to T1&T2. As a result, both are in cutoff state, so no flow of current through the beeper, keeping it in silent mode. Likewise, no flow of current in the relay, and so bulb B1 do not glow.
If the reference voltage at pin-3 of IC2 is superior than sensor voltage at pin-2 of IC2, o/p goes high automatically. This indicates that light is falling on LDR1. High o/p of IC2 is fed to T1 and T2. As a result, both transistors are in on (active) state. The flow of current through the buzzer & relay. The buzzer generates a loud alarm to alert you or people around you and, at the same time, bulb B1 glows as the circuit finishes through relay RL1’s contacts.
Operation of Electronic Eye Security System
- Initially, connect the circuit of the electronic eye security system as shown in the above circuit diagram on the bread board.
- Now connect the battery for the supply voltage of 9v.
- Place the LDR (Light Dependent Resistor) in the light.You can detect no sound is generated from the buzzer.
- Place the light dependent resistor in the dark, then the buzzer starts buzzing. Light emitting diode connected to the buzzer also starts flashing.
- As the light intensity dropping on the LDR growths sound generated by the buzzer increases.
Applications of Electronic Eye Security System
- This system can be used in door bell circuits.
- This can be used in a garage door opening and closing circuits.
- This system can be used in security applications.
Thus, this is all about electronic eye security system using photo-sensing (LM393). We hope that you have got a better understanding of this concept.Furthermore, any doubts regarding this concept or to implement any electrical and electronic projects, please give your valuable suggestions by commenting in the comment section below. Here is a question for you, What is the function of LM393?
There are different types of projects based on the temperature indicator. Now, here we are explaining about the temperature indicator with the LED display by using a temperature sensor. This project shows the use of a V/F converter monitoring temperature in degree Fahrenheit (F). The benefits of the LED temperature indicator are it can calculate the room temperature, atmospheric temperature, and body temperature. This article discusses the block diagram & circuit diagram of the LED temperature indicator.
During traveling on the bus or the train, we carry many things like luggage and costly things, but we have the fear that somebody might steal the luggage. So to guard our luggage, we usually lock our luggage through the old methods with the help of lock and chain. After all these, we still stay in fear that any thief may break the chain and take away all the valuable things. To overcome this problem, here is a system, namely luggage security alarm circuit which is based on the NAND gate. The main aim of this system is to generate an alarm when any unauthorized person tries to steal your luggage. This system is very useful when you travel in the night time. Another application of this luggage security alarm system is, you can use in your home for the security from the theft.
The term biometric is derived from Greek words such as bio (life) and metric (to measure). The Biometric is used to recognize his or her behavior characteristics of a person. This kind of identification is preferred over traditional methods, comprising PIN numbers and passwords for its accuracy and case sensitiveness. Based on the development, this system can be used as an identification system. These systems are divided into various types like fingerprints, vein pattern, DNA, hand geometry, voice pattern, signature dynamics, iris pattern, and face detection. This article discusses new infrared LED for biometric identification applications.
Generally, in any kind of work, several tasks need to be done in the progression of meeting the purposes and goals intended at accomplishing through that effort. In addressing “what type of task need to be achieved”, numerous inputs and outputs and the complete contents of these tasks are defined and planned in a logical manner, which is jointly stated to as the “process”. In order to complete the expansion of software as a product, several types of tasks need to be achieved with layers like in any other productions. The activities estimated necessary in the making of a software development process will jointly become the so-called embedded systems development process when they are planned in a logical manner.
The programmable timer is a simple circuit in the series of a timer. This timer circuit is used to switch ON/OFF a device. The time period of this circuit is from 8 seconds to 2 hours. The programmable timer works with the single input and in some other conditions, it may use a pair of signals. Based on the timer event the timer will exist in many processors. The digital timers are used in several types by LCD, LED and gives longer service. The programmable timer is used for measurement, display.
What is a Programmable Timer?
The programmable timer is a device which is used for loading a switch ON and OFF after a predetermined delay as per the condition. According to the user personal specs, the delay timings are adjustable. The ON time delay and OFF time delay are independently capable of setting and it has become the most important feature of a programmable timer circuit.
Programmable Timer Circuit using 555 Timer IC
This circuit is constructed by two integrated circuits. The integrated circuit IC1 is a 555 IC and the IC2 is a 7442 IC. The 555 IC is used as a monostable mode, therefore when the output is low the pin-2 of the trigger is high and vice-versa.
This circuit is constructed by two integrated circuits. The integrated circuit IC1 is a 555 IC and the IC2 is a 7442 IC. The 555 IC is used as a monostable mode, therefore when the output is low the pin-2 of the trigger is high and vice-versa. The preset time output is high when it is determined by the value of capacitor C1 with its corresponding preset through the switch SW5.
The IC 7442 is a second integrated circuit (IC2), it is used for selecting the time duration period. There are 10 outputs from the programmable timer are connected to the 3-volt relay respectively. Where preset VR1 to VR10 are connected to an RL1 trough RL10 respectively. The following table shows the approximate binary codes. The resistor values of R1, R2, R3, R4, R6, R7 is equal to the 10Kohms. The capacitor values of C1 and C2 are 220 µF/25V, 0.01 µF respectively.
|Preset||SW4 8||SW3 4||SW22||SW1 1|
Programmable Digital Timer Circuit
A timer is a type of clock used for measuring the time intervals. The timers are classified into two different types like counting upwards and counting downwards. The designs of the timer are completely needed in the industry that means keeping time on certain devices and the timers are the mechanical devices used in the clockwork mechanisms. In the market, the digital logic circuit has more popular with less price and individual timers are implemented with the single chip circuit design. The development of two electromechanical timers is designed to produce more precise time measurement.
The first one is the principle of heat extension to increase the temperature of metal finger prepared by two different metals varying the rate of thermal expansion. If the current flows through the metal, therefore heat will start and on one side of the metal, the heat will produce more quickly than the other side of the metal. Thus, there is a move of electrical contact away from the electrical switch contact. The second one is the small AC motor, which is a predetermined rate suitable for the applications of alternating current.
The following circuit diagram shows the adjustable digital timer circuit by using the microcontroller of PIC16F628A. It is a programmed to plan the ON and OFF operations of an electrical appliance. The digital timer circuit consists of three parts like power supply, display and control circuit. The applied voltage is depending on relay voltage and the range of the voltage is from 5V to 12V. If you use 5V power supply then you can’t use the LM7805 regulator IC and 5 volts is applied directly. If you are applying less than 12 volts or greater than the 5 volts, therefore, you have to use the regulated IC and PIC is used as an internal oscillator.
To display the numbers there are two variations like 4dg_tmr_min.hex and 4dg_tmr_hr.hex. The first file is used to display the minutes and seconds and timer is from 1 second to 60 minutes. The other file is used to display the minutes and hours and it is from 1 minute to 24 hours and hours and minutes are displayed on the seven segment layer.
Simple Programmable Timer Circuit
This timer circuit is build by using the versatile IC 4060. The circuit has very easy configuration by using the versatile IC’s and the circuit requires a minimal number of components to get the running unit. The two IC’s are wired up with the two independent modes, therefore, timing is different for two sections. These two integrated circuits are coupled with each other and their initializing has become interconnected.
The output of the upper IC is united to the reset input of the lower IC through the transistor in such way that the output goes high for an upper IC and it triggers the operation of the lower timer. The lower IC starts counting, its output goes high. Stops the upper IC counting, it will reset to its original state and the process is initiated from the starting. Simply we can say that as long as the upper ICs timing does not fall the lower IC remains idle. Even though upper IC’s lapses and its output became high and it switches the output load and lower IC operation. The upper IC is used for determining how long the load will be switched ON and lower IC is used for determining at what time the switch will be OFF.
Applications of Programmable Timer
- The programmable timer is used for the measurement purpose.
- Display and control in appliances that have variants.
Advantages of Programmable Timer
- In most of the timing applications, the 555 timers IC is used
- The 555 timer can generate pulse width modulation from kilowatts to megawatts
- The 555 timer can act as monostable, bistable and astable mode
- The complex circuit can avoid by using the IC4060
- The ic4060 circuit is more superior to the 555 timer IC
This article will describe the programmable timer circuit with their appliances. I hope by reading this article you gained some basic information about the programmable timer circuits. If you have any queries about this article or about electrical projects based on engineering please feel free to comment in the below section. Here is the question for you, What are the functions of programmable timer?
Simple Programmable Timer Circuit blogspot
The term PIC stands for the peripheral interface controller was developed in the year 1993 by “Microchip Technology”. Firstly, this controller was developed for supporting PDP computer to regulate its peripheral devices, and thus, termed as a peripheral interface device.PIC microcontrollers are very fast and executing a program can be made easy compared with other controllers. The architecture of this microcontroller based on “Harvard architecture”. The specifications of this microcontroller include wide availability, ease of programming, serial programming capacity, large user base, interfacing of microcontroller with other peripherals, etc.