RANGKAIAN MIKROKONTROLER at89s51 JAM DIGITAL

RANGKAIAN JAM DIGITAL MIKROKONTROLER at89s51

A digital clock is 1 that displays time digitally. The circuit explained here displays time with two ‘minutes’ digits and two ‘seconds’ digits on four seven segment displays. The seven segment and switches are interfaced with 8051 microcontroller AT89C51. This circuit may be used in vehicles, houses, offices and many others. The moment the Vcc supply is supplied to this circuit, the clock begins from 00:00. Time is displayed on four 7 segments (in frequent anode configuration) by utilizing the notion of multiplexing. That is reached by utilizing timer interrupt (Timer0) of AT89C51 which is configured to refresh 7 segments. The segments are refreshed numerous periods in the 2nd for simultaneous show. The clock runs which has a delay of precisely a single 2nd. Timer1 is used to produce a time delay of a single second. The info pins (a-h) of the many segments are interconnected and get signal from port P2 in the microcontroller. The control or allow pins (popular anode) are connected to pins 1-4 of port P1 (P1^0 - P1^3).

The number on 4th section (displaying the unit digit of 2nd) is incremented as soon as in the 2nd since it goes from 0 to nine. The range on 3rd section is incremented just after every 10 seconds from 0 to 5. Hence seconds are displayed different from 00 to 59. The digit to the 2nd section variations after every 60 seconds (a minute) from 0 to nine etc. So the clock runs for an hour and following that it resets to zero once more

source:engineersgarage.com

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AT89S8252 Electronic Voting Machine Circuit Diagram

AT89S8252 Electronic Voting Machine Circuit Diagram

Now-a-days Electronic voting machines are being used effectively. The confidence of the voter in its flawless working is gradually building up and these machines are thus becoming quite popular throughout the country.

Features of the electronic voting machine include avoidance of invalid votes and reduction of counting time and the consequent expenditure incurred on manpower deployment. By using the Microcontroller the voting machine can be built up easily and it will make simple to operate.

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Electronic Safety Lock with Phonecard

Electronic Safety Lock with Phonecard

Circuit description

This ambit its not address any abstracts to the telecard. The ATtiny26 apprehend the 16 aboriginal bytes of telecard and afresh abundance them to centralized eeprom of ATtiny26.

Back you admit any telecard to the aperture (telecard`s base) it will apprenticed the about-face SW1. The ATtiny it will acquire that new agenda admit in the aperture and go to apprehend it. Temporary will save the 16 aboriginal bytes of the agenda to the RAM and afterwards the ATtiny will chase in centralized eeprom to see if this telecard is registered to the system. if not, it will aces the Red LED. The ATtiny acquire 8 groups of 16 bytes each, arbitrary 8*16=128 bytes of eeprom memory.

The ATtiny of this ambit its alive with centralized RC oscillator at 1MHz, that is the absence ambience from the factory.

1. Annals a telecard to the system:

With any telecard in to the slot, columnist the SW2 to annals the agenda to the system. The ATtiny will chase the centralized eeprom for abandoned anamnesis accumulation (1 group=16 bytes with $0F values). If there is abandoned group, it will apprehend the 16 bytes from RAM and abundance them to the eeprom. Then, the ATtiny will reboot, displace the telecard, apprehend it afresh and analysis if the agenda is registered (by analyze the 16 bytes of telecard, with 1 accumulation at the time, with centralized eeprom) .

Now it will awful the Red LED and aces the blooming LED because we acquire annals this telecard to the system. At the aforementioned time it will arm the broadcast affiliated to PB6 pin via BC547.

The centralized eeprom of ATtiny26 is 128 bytes. So, we can annals up to 8 telecards (keys) to this memory.

(8 telecards)*(16 bytes for anniversary telecard)=128 bytes of centralized eeprom

2. Unregister an registered telecard from the system:

If for some acumen we don't appetite to use any of 8 registered telecard, we can unregister it from the system. We acquire to admit this agenda to the slot, the ATtiny acquire it (by aces the blooming led). If we columnist the SW3, the ATtiny will chase to centralized eeprom to acquisition were the 16 bytes are stored and annul them by address the amount $0F to this anamnesis group. Now the ATtiny will reboot, apprehend afresh the telecard, analyze the aboriginal 16 bytes of the agenda with the centralized eeprom and because we acquire unregister this agenda it will aces the red LED. This telecard is unregistered now. We can annals the agenda afresh if we appetite to, by chase the footfall 1.

3. Abolish absolute centralized eeprom of ATtiny26:

If we acquire annals 8 telecards to the arrangement and will try to annals 1 added (9th), back we columnist SW2 to annals the card, the ATtiny it will beam the Red and Blooming LEDs 4 times alternately. The alone way to annals some added telecard, is to unregister some one of 8 registered cards (step 2.) or to abolish absolute eeprom (writing the amount $0F to all locations). To abolish absolute eeprom (128 bytes 0-127) we acquire to columnist the SW3 button with NOT any agenda central to the slot, for 2 seconds, to ensure the ATtiny that we are not columnist the button SW3 by asccident . At this case the ATtiny it will beam the Red LED 4 times. Afterwards that, the centralized eeprom of ATtiny it will cleared.

The ethics of absence centralized eeprom bytes are $FF. If we admit the telecard with amiss pins position (reversely), the ATtiny will apprehend 16 bytes with $FF ethics because of centralized pullup resistor of PB4. If we let the eeprom to absence amount ($FF), back we admit any agenda (anything with telecards dimensions) aloof to columnist the about-face SW1, the ATtiny will apprehend 16 bytes with $FF amount (because centralized pullup resistor of PB4) and will arm the relay. By set the eeprom to $0F value, at the appearance of programming the safety_lock.eep book of ATtiny, we assure the arrangement from this mistakes.

You can alter the $0F amount of the antecedent cipher with the amount of your choice, for archetype $AB or $CF etc. Remeber to alter all the $0F ethics of the antecedent code, not alone the 128 bytes of eeprom. The telecard abject and the capital ambit are body them to altered boards for added article .

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Oscilloscope Based on PIC18F2550 Microcontroller

Oscilloscope Based on PIC18F2550 Microcontroller

Description

The operating voltage of the ambit is 12V DC. By this voltage, the ability accumulation is bearing 2 voltages. +8.2V for IC1 and +5V for IC2 and IC3. This ambit can admeasurement from +2.5V to -2.5V or from 0 to +5V abased by S1 position (AC or DC input). By application delving with 1:10 analysis you can admeasurement about 10 times college voltages. Moreover, with S2 you can accomplish an added analysis by 2 the ascribe voltage.

Programming The ATmega32

Burn the ATmega32 with AVR_oscilloscope.hex and baddest alien bright at the fuses section.

After that, you Must attenuate the JTAG interface from your ATmega32 microController. If you don't do that, the mega32 will appearance you the antecedent awning and back it go to the oscilloscope awning it will restart anon to the antecedent awning and it will break there for ever.

Calibrations

The alone 2 things you accept to calibrate is the LCD adverse trimmer P2 and the P1, to move the axle at the centermost of the LCD. To do that, administer alone the ability accumulation to the ambit and acclimatize the P2 up to the point you will see bright the appeared pixels on the screen. Then, acclimatize the P1 up to the point the axle is confused at the average of the LCD (at the accumbent band of the cross).

Usage

You can move the axle up or bottomward the awning by acute the buttons S8 or S4 appropriately to admeasurement the voltage of the signal. 1 volt is demography up 1 aboveboard height. With S7 and S3 you can access or abatement the altitude speed. This oscilloscope has an automated trigger. That means, if you accept a connected arresting (ex a triagle waveform) the auto activate will assignment perfect. If your arresting is not abiding (ex a consecutive transmittion) you can benumb the awning by acute S6 switch. At his case you can get a snapshoot of your measurment signal. By the time you absolution the S6, the snapshoot will end.

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Interfacing 7-segment Display using 7447 decoder

The Light Emitting Diode (LED), finds its place in many applications in this modern electronic fields. One of them is the Seven Segment Display. Seven-segment displays contains the arrangement of the LEDs in “Eight” (8) passion, and a Dot (.) with a common electrode, lead (Anode or Cathode). The purpose of arranging it in that passion is that we can make any number out of that by switching ON and OFF the particular LED’s. Here is the block diagram of the Seven Segment LED arrangement.

Pin configuration of a seven segment display:

LED’s are basically of two types:

1. Common Cathode (CC)
   All the 8 anode legs uses only one cathode, which is common.
2. Common Anode (CA)
   The common leg for all the cathode is of Anode type.

For the discussion purpose, we use CC LED, where by just reversing the logical voltages we can implement the same for CA LED also.

In a CC LED, all the 8 legs (’a’ through ‘h’) are of anode type and the common cathode will be connected to the GND of the supply. By energizing any of the legs with +5 Volts will lead to switch the correspondent segment ON. In the microprocessor binary system, 0Volts will be considered as Binary 0, and 5Volts will be considered as Binary1. Considering these two condition, we can make an arrangement as the microcontroller gives OUT the 0s and 1s through its ports, which is connected to the 8 legs of the LED. Of course, we can control the Port Output; implicitly we can Switch-ON required legs of the display.

There 2 methods of interfacing LED with the Microcontroller Intel 8051/8951.

1. Using lookup table. This uses 7 output pins of microcontroller
2. Using 7447 decoder. This method uses 4 output pins of microcontroller

The difference between the two main methods is simple and clear. In both the cases, microcontroller communicates with external world through its ports. But, in the 1st case, we connect all the 8 pins of the port directly to the LED and control the voltage through the ports manually to display the desired number. But, in the second case, we send the BCD of the number that we wanted to display to a middleware IC 7447, the BCD to LED code converter, which by itself gives out the correspondent 7 segment codes to the LED.

Here we explain using lookup table. Click here for the method “using 7447 decoder”

Using 7447 decoder:

The IC7447 is a BCD to 7-segment pattern converter. This setup is the advanced form of the setup where we entered the patterns manually to display the desired character. Here in this case, the IC7447 takes the Binary Coded Decimal (BCD) as the input and outputs the relevant 7 segment code. We connect first four pins of the microcontroller Port 2 to the 7447 and the Output 8 pins of 7447 to the 8 legs of the LED as shown in the figure. Te circuit diagrams are shown below, the first figure is interfacing the CA LED where as the second is of CC LED. The number required to display is sent as the lower nibble of the Port 2 of the Microcontroller. The 7447 converts the four input bits (BCD) to their corresponding 7-segment codes. The outputs of the 7447 are connected to the 7-segment display.

Circuit diagram for interfacing Common Anode 7-Segment Display

Circuit diagram for Common Cathode 7-Segment Display

Program:

This program displays characters 0 through 9 on seven-segment display
using IC 7447 as the middle wear.

 again: mov a,#00h                  ; Start form zero
    up:  mov p2, a                  ; Move to Port 2
         mov r3,#255                ; Delay
    D1:  mov r1,#255
     D:  djnz r1,D
         djnz r3,D1
         inc a
         cjne a,#0ah,up
         sjmp again

Via : http://electrofriends.com/

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8951 Microcontroller Robotic Car Project

Robotic Car is a miniature prototype car powered by batteries whose various movements can be control either manually or automatically, or the combination of both. Here the command is given through keyboard; it would have been better if we used IR remote control or something of that kind rather than using keyboard for commanding. However, by realizing the complexities we have made simple using keyboard.

Block diagram of the project:

Some photographs of this model:

Robotic car model

Robotic car model

Project Description:

Keyboard section:

There are six switches in this section. They are

1. Turn left.
2. Turn right.
3. Stop.
4. About turn.
5. Park left.
6. Park right.

Circuit diagram of keyboard is shown bellow.

Keyboard circuit of the Robotic car

Car section:

There are many sub sections in this section. They are

Motor:

We are using a 5V dc motor to drive the vehicle. The speed of the vehicle and its strength is controlled by the proper use of pulley. The rear wheel of the vehicle is connected to this motor through a pulley. This motor is meant for moving the vehicle both in forward and backward direction. Microcontroller (8051) controls the forward and backward movement of the vehicle in the following manner:

Circuit diagram of Motor connection

Here in the above circuit, T1, T2, T3, T4 are the NPN power transistor (2N3055). A0, A1, A2, A3 are the signals coming from the micro controller. With the specific combination of A0, A1, A2, A3 we can change the direction of rotation of motor as follows:

Case I: When A0=high; A3=high; & A1=low; A2=low
The motor rotates in clockwise direction

Case II: When A0=low; A3=low; & A1=high; A2=high
The motor rotates in anti-clockwise direction

Case III: When A0=low; A3=low; A1=low; A2=low
The motor stops the rotation.

Via: http://electrofriends.com

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Water Level Indicator Cum Controller

The present concept implements controlling of pump which pumps water from the sump (underground tank) to the overhead tank, using 8951 microcontroller.

The control panel, i.e. the main control unit of the system which consists of the primary control switches, pump indicator, siren and level indicators. The visual example of how switches And the indicators can be placed as shown the figure below.

Front view of the model

In the figure shown above there are total of nine LEDs, four of which indicates the water level in the tank, another four indicates the water level in the sump and one LED indicates whether the pump is ON/OFF. It also consists of three switches.

1. Switch 1 is the main power switch which is used to activate the system.
2. Switch 2 is used to select whether to operate the pump in AUTO or MANUAL mode.
3. Switch 3 comes to picture only when the system is operated in MANUAL mode. It controls the direct activation of the pump.

Description :

As you can see in the above diagram, port 0 is exclusively used as an input port which takes the information regarding the water level in the sump as well as in the overhead tank.

Port 1 is used as output port which is connected to the indicator that indicates the water level in both the tanks.

Port 2 is used as in/out port, it takes the input from switch 2 and switch 3 and gives the output which is connected to pump indicator, siren and the relay which controls the switching of the pump.

Working of the system:

There are two modes of working for the system

1. Manual mode
2. Auto mode

Which is controlled by switch 2 (refer control panel diagram)

Manual mode:

When the system is active and in manual mode, it only indicates the water levels in the tanks and it doesn’t control any working of the pump. To activate the pump in manual mode switch 3 is used.

In this mode the operator should manually control the working of the pump. As in case if the tank is full, operator should switch of the pump which is not the case when compared to auto mode.

Auto mode:

When the system is active and in auto mode, it only indicates the water levels in the tanks and it controls the working of the pump.

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Rangkaian Mikrokontroller AT89C2051 Digital Code Lock

A project called ‘Digital Code Lock using AT89C2051′. LCD is used for display and a keyboard is used to input the keys. This project source code is written in C. Both the C files and hex files are given for download.

A Brief Description:

This a simple project with efficient hacking prevention from Brute Force etc. The basic user lock is of 5 Digits and Master Lock is of 10 digits so its not easy for an intruder to break the lock unless you keep the code simple.

The input is taken from a 4×3 Keypad (please see the schematic for more information) and Display the user input on a 2×16 LCD. A pin is assigned as output for activating and deactivating the lock. For demonstration i have connected an LED to that pin.

From user side:
The user has two options either he/she can use its own 5 digit code or use the default 5 digit code. If user has to do setup his own code, then he has to enter “12345″ and press ‘#’. After this.. controller will ask for 10 Digit master password which is preprogrammed in the controller. Entering master lock, user can enter the new 5 digit code for the lock and press ‘#’ to save it.

Using the Keypad:
Keypad has 12 keys (4×3) starting from 1,2,3,4,5,6,7,8,9,*,0,# (please see the schematic for layout). Numeric keys are used for entering numbers. ‘*’ is used as the Cancel key and ‘#’ is used as the Enter key.

Download File Information:

1. LCD.C – 4-Bit LCD Drivers
2. LCD.H – LCD function prototypes and other declerations
3. Lock.C – code for lock functioning
4. LOCK.H – lock function declarations
5. KEYPAD.C – Keypad drivers
6. KEYPAD.H – Function declarations
7. DELAY.C – Delay Functions
8. DELAY.H – Function Prototypes only
9. MAIN.C – Main function!
10. Digital Code Lock Schematic – PDF file of orcad schematic

Download the source codes by clicking here

By Ajay Bhargav
http://rickeyworld.info

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Real Time Clock CAT89C4051 Circit Diagram

Real Time Clock CAT89C4051 Circit Diagram

here is a clock project where CAT89C4051 is used as RTC. LCD is used for display. Using CGRAM area of LCD you cn create cistome characters. Here you will be able to see big and better digits in LCD. The digits are twice the size of the normal digits.

PCB design for project is also given below. A nice PCB with single layer design. This PCB is recommended for the above project

The silk screen is not so good. but you can edit it as you want and make it look better.

Here the program is written in C and hex file is generated using Keil C compiler. You can directly use ‘Clock.hex’ file.

Download the source codes by clicking here

By Ajay Bhargav
http://rickeyworld.info

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AT89Sxx Cheap and Simple Learning Board

A Circuit or learning MCS-51 Microcontrollers.

The AT89Sxx learning board features,

• Designed for new ISP chips, 89S51, 89S52, and 89S53, 40-pin DIP,
• In System Programmable (ISP) through the 6-pin header and a jumper, (no need external programmer),
• TxD and RxD serial port for communicating with serial devices,
• 32 bit GPIO,
• Onboard rectifier and +5V DC voltage regulator,
• Single Sided PCB design.

Hardware

The board design is kept as simple as possible so that everone can make the learning board easily. The schematic shown below shows the complete hardware schematic of the AT89Sxx learning board. PORT0, PORT1, PORT2, and PORT3 are available for interfacing external devices. P3.0 and P3.1 are being used for RS232 interface.

Components:

R1 330 1/4W +/-5%

R2 10K 1/4W +/-5%

R3-10 10K 1/4W +/-5% (for pull up on P0)

C1 1000uF/16V electrolytic capacitor

C2 100uF/16V electrolytic capacitor

C3 100nF multilayer or ceramic

C4 10uF/16V electrolytic

C5,C6 33pF ceramic

D1 1N4001 / 1N4002 silicon rectifier diode

D2 LED

U1 LM7805, voltage regulator

U1 AT89S51, AT89S52 or AT89S53

X1 Crystal 1MHz – 33MHz (11.0592MHz is suitable for standard BAUD rate generator using timer1, says 9600 )

DB25 parallel port, 25pins connector

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Home Security System Circuit Using AT89S52

Home Security System Circuit Using AT89S52

Security is a prime concern in our day-today life. Everyone wants to be as much secure as possible. An access control for doors forms a vital link in a security chain. The Microcontroller based Home Security System can be adopted at Home it has various type of Sensors. In our Project we have magnetic sensors, Wire Loop sensors, Fire sensors. The system is fully controlled by the 8 bit microcontroller AT89C52 which has a 8Kbytes of ROM for the program memory.

The Microcontroller will continuously monitors all the Sensors and if it found any security problem then the Microcontroller will switch on the Alarm until the Reset button was Pressed.

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FingerPrint Based Security System Using AT89S52

FingerPrint Based Security System Using AT89S52 Pcb

Personal Safes are revolutionary locking storage cases that open with just the touch of your finger. These products are designed as secure storage for medications, jewelry, weapons, documents, and other valuable or potentially harmful items.These utilize fingerprint recognition technology to allow access to only those whose fingerprints you choose. It contains all the necessary electronics to allow you to store, delete, and verify fingerprints with just the touch of a button. Stored fingerprints are retained even in the event of complete power failure or battery drain.These eliminates the need for keeping track of keys or remembering a combination password, or PIN. It can only be opened when an authorized user is present, since there are no keys or combinations to be copied or stolen, or locks that can be picked.

In this project the fingerprint module from Miaxis Biometrics is used. It can store up to 750 finger prints on its own memory. It can be controlled through its serial port.

The microcontroller AT89S52 interact with the module. You can Add a fingerprint, Delete a fingerprint and Identify the fingerprint.

To add a fingerprint, just show the finger on the module and press the ADD key. Now the microcontroller will send the ADD command to the module and the module will add it into the memory.
To delete the finger follow the same as above.

To identify the finger, press the Identify button and if the finger matches then the Relay is complemented. Also the fingerprint ID is displayed over the LCD display.

For more details about the Fingerprint module, please check the datasheet and you can get it from the datasheets page.

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Digital Visitor Counter With AT89C2051

Digital Visitor Counter With AT89C2051 Schematic

Digital visitor counter is a reliable circuit that takes over the task of counting Number of Persons/ Visitors in the Room very Accurately. When somebody enters into the Room then the Counter is Incremented by one and when any one leaves the room then the Counter is Decremented by One. The total number of Persons inside the Room is displayed on the seven segment displays.
The microcontroller do the above job it receives the signals from the sensors, and this signals operated under the control of software which is stored in ROM

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Digital Calender Using AT89C2051 Microcontroller

Digital Calender Using AT89C2051 Microcontroller Schematic

This Project Digital Calendar using Microcontroller is an advanced digital calendar, which displays the Date, Day, Month over the LED display. It has an 8 bit Microcontroller which runs on the Program embedded on its ROM. Separate LED’s are provided for the date, day, and month. The system has an battery backup so that it can run over all the time even during the power failure.

Totally there are 31 LED’s for indicating the date and 12 LED’s for indicating the Month and 7 LED’s to indicate the day. All the above systems are controlled by the Microcontroller. In our project we are using the popular 8 bit microcontroller AT89C2051. It is a 20 pin microcontroller.

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