CONTENTS INTRODUCTION COMPONENT USED 8051 MICROCONTROLLER ARCHITECTURE STEPPER
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CONTENTS • • • • INTRODUCTION COMPONENT USED 8051 MICROCONTROLLER ARCHITECTURE STEPPER MOTOR DIODE RESISTOR CRYSTAL OSCILLATOR VOLTAGE REGULATOR CAPACITOR MOMENTARY SWITCH LCD CIRCUIT DIAGRAM BIBLIOGRAPHY
INTRODUCTION • The microcontroller based Door locker is an access control system that allows only authorized persons to access a restricted area. The system is fully controlled by the 8 bit microcontroller AT 89 C 2051 which has a 2 Kbytes of ROM for the program memory. • The system has a Keypad by which the password can be entered through it. When the entered password equals with the password stored in the memory then the gate gets open. If we entered a wrong password then the Alarm is switched on. • The default password is set. There is an button which should be placed inside the door so that the person inside can open/close the door.
SR. NO. COMPONENT USED QUANTITY 1. 89 C 51 MICROCONTROLLER 1 2. DIODE(4007, . 7 V) 4 3. ULN 2003 1 4. STEPPER MOTOR 1 5. RESISTANCE(10 K-OHM) 6 6. RESISTANCE(4. 7 K-OHM) 7 7. CRYSTAL OSCILLATOR (12 MHZ) 1 8. TRANSFORMER(220 V, 909) 1 9. ELECTROLYTIC CAPACITOR (100 MICROFARAD, 470 MICROFARAD) 1, 1 10. VOLTAGE REGULATOR (7805)(+5 V) 1 11. LCD(2*16, JHD 162 A) 1 12. MOMENTARY SWITCHES 17 13. CONNECTORS (16 PIN, 5 PIN, 2 PIN) 1, 1, 1
89 C 51 MICROCONTROLLER • 89 C 51 • The AT 89 C 51 is a low-power, high-performance CMOS 8 -bit microcomputer with 4 K • Bytes of Flash programmable and erasable read only memory (PEROM). • The device is manufactured using Atmel’s high-density nonvolatile memory technology and is Compatible with the industry-standard MCS-51 instruction set and pin out. • The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional non-volatile memory programmer. • By combining a versatile 8 -bit CPU with Flash on a monolithic chip, the Atmel AT 89 C 51 is a powerful microcomputer which provides a highly-flexible and cost-
89 c 51 PIN DIAGRAM
FEATURES • The AT 89 C 51 provides the following standard features: 4 K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16 -bit timer/counters, five vector two-level interrupt architecture, a full duplex serial port, and on-chip oscillator and clock circuitry. • In addition, the AT 89 C 51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. • The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. • The Power-down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset. • The AT 89 C 52 implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a parallel address space to the Special Function Registers. • That means the upper 128 bytes have the same addresses as the SFR space but are physically separate from SFR space. • When an instruction accesses an internal location above address 7 FH, the address mode used in the instruction specifies whether the CPU accesses the upper 128 bytes of RAM or the SFR space. Instructions that use direct addressing access SFR space. new features. • In that case, the reset or inactive values of the new bits will always be 0.
STEPPER MOTOR • A stepper motor (or step motor) is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps. • The motor's position can be controlled precisely without any feedback mechanism (see Open-loop controller), as long as the motor is carefully sized to the application. • Stepper motors are similar to switched reluctance motors (which are very large stepping motors with a reduced pole count, and generally are closed-loop commutated. )
Stepper Motor Driver IC ULN 2003
CHARACTERISTICS OF STEPPER MOTOR • Stepper motors are constant power devices. • As motor speed increases, torque decreases. • The torque curve may be extended by using current limiting drivers and increasing the driving voltage. • Steppers exhibit more vibration than other motor types, as the discrete step tends to snap the rotor from one position to another. • This vibration can become very bad at some speeds and can cause the motor to lose torque. • The effect can be mitigated by accelerating quickly through the problem speeds range, physically damping the system, or using a micro-stepping driver. • Motors with a greater number of phases also exhibit smoother operation than those with fewer phases.
DIODE • A diode is a two-terminal electronic component that conducts electric current in only one direction. • The term usually refers to a semiconductor diode, the most common type today, which is a crystal of semiconductor connected to two electrical terminals, a P-N junction.
RESISTANCE • The electrical resistance of an object is a measure of its opposition to the passage of a steady electric current. • An object of uniform cross section will have a resistance proportional to its length and inversely proportional to its cross-sectional area, and proportional to the resistivity of the material.
CRYSTAL OSCILLATOR • A crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. • This frequency is commonly used to keep track of time (as in quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. • The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits designed around them were called "crystal oscillators".
VOLTAGE REGULATOR • A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. • It may use an electromechanical mechanism, or passive or active electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.
CAPACITOR • A capacitor or condenser is a passive electronic component consisting of a pair of conductors separated by a dielectric (insulator). • When a potential difference (voltage) exists across the conductors, an electric field is present in the dielectric. • This field stores energy and produces a mechanical force between the conductors. • The effect is greatest when there is a narrow separation between large areas of conductor; hence capacitor conductors are often called plates
MOMENTARY SWITCH • In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another. • The most familiar form of switch is a manually operated electromechanical device with one or more sets of electrical contacts.
LCD • The JHD 162 A LCD is fully compatible with the HD 44780 LCD. • Hence, the same set of codes will work for both. It is a 16× 2 LCD module i. e. it has 16 columns and 2 rows for display. • It can operate in either 8 bit mode or 4 bit mode. • In 8 bit mode, an 8 bit is data is sent to the LCD from the MCU whereas in 4 bit mode, 4 bits of data are sufficient to operate it.
• FEATURES • Display construction………………. . . • Display mode………………. . • Display type………………. • Backlight…………………. • Viewing direction……………. • Operating temperature……………… • Driving voltage……………. …. • Driving method……………. . • Type……………………… • Number of data line………… • Connector…………………. . 16 Characters * 2 Lines TN/STN Positive Transflective LED(B/5. 0 V) 6 o’clock Indoor Single power 1/16 duty, 1/5 bias COB (Chip On Board) 8 -bit parallel Pin
CIRCUIT DIAGRAM • BLOCK DIAGRAM
• BASIC CIRCUIT
BIBLOGRAPHY • SEDRA SMITH • INTRODUCTION TO 8051 MICROCONTROLLER … MAZIDI • INTRODUCTION TO 8051 MICROCONTROLLER … AYALA • www. wikipedia. com