Remote ac power control by android application with lcd display

Remote AC Power Control
by Android Application
with LCD Display

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Remote AC Power Control by Android
Application with LCD Display
Introduction
 The project is designed to control AC power to a load by using firing angle
control of thyristor. Efficiency of such power control is very high compared
to any other method. Remote operation is achieved by any smart-
phone/Tablet etc., with Android OS, upon a GUI (Graphical User Interface)
based touch screen operation. The project uses zero crossing point of the
waveform which is detected by a comparator whose output is then fed to
the microcontroller.

Block Diagram

Hardware Requirements
 8051 series Microcontroller
 LM358
 Opto isolators
 SCRs
 Push Button
 Transformer
 Diodes
 Voltage Regulator
 Resistors
 Capacitors
 Crystal
 Lamp
 Bluetooth Device

Software Requirements
 Keil compiler Languages:
 Embedded C or Assembly
 Android Application.

Embedded Systems
 A combination of hardware and software which together form a
component of a larger machine.
 An example of an embedded system is a microprocessor that controls an
automobile engine.
 An embedded system is designed to run on its own without human
intervention, and may be required to respond to events in real time.

Embedded Systems

Micro Controller
 Compatible with MCS- 51 Products
 8K Bytes of In-System Programmable (ISP) Flash Memory
 4.0V to 5.5V Operating Range
 Crystal Frequency 11.0592MHZ
 Three-level Program Memory Lock
 256 x 8-bit Internal RAM

Micro Controller
 256 x 8-bit Internal RAM
 32 Programmable I/O Lines
 Three 16-bit Timer/Counters
 Eight Interrupt Sources
 Full Duplex UART Serial Channel
 Watchdog Timer

Liquid Crystal Display (LCD)
 Most common LCDs connected to the microcontrollers are 16x2 and 20x2
displays.
 This means 16 characters per line by 2 lines and 20 characters per line by 2
lines, respectively.
 The standard is referred to as HD44780U
 It refers to the controller chip which receives data from an external source
(and communicates directly with the LCD.

AT89S52
 AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller
with 8K bytes of in-system programmable Flash memory.
 The device is manufactured using Atmel’s high-density nonvolatile memory
technology.
 It is compatible with the industry-standard 80C51 instruction set and
pinout.
 The on-chip Flash allows the program memory to be reprogrammed in-
system or by a conventional nonvolatile memory programmer.

PIN Diagram Of AT89S52

MOC3021 ( OPTO COUPLER )
 Opto-couplers are made up of a LED and a light sensitive device, all
wrapped up in one package.
 No electrical connection between the two devices.
 The light sensitive device may be a photodiode, phototransistor, or more
esoteric devices such as thyristors, triacs etc.

Pin Description of MOC3021

LM 358 (OPAMP)
 Internally frequency compensated for unity gain.
 Large dc voltage gain: 100 Db.
 Wide bandwidth (unity gain): 1 MHz (temperature compensated)
 Wide power supply range:
• Single supply: 3V to 32V
• or dual supplies: ±1.5V to ±16V

LM 358 (OPAMP)
 Very low supply current drain (500 µA)-essentially independent of supply
voltage.
 Low input offset voltage: 2 mV
 Input common-mode voltage range includes ground.
 Differential input voltage range equal to the power supply voltage.

LM 358 Pin Diagram
1- Output 1
2- Inverting input
3- Non-inverting input
4- VCC
5- Non-inverting input 2
6- Inverting input 2
7- Output 2
8- VCC+

Thyristor
 A thyristor is a solid-state semiconductor device with four layers of
alternating N and P-type material.
 It acts exclusively as a bistable switch, conducting when the gate receives
a current trigger.
 Continuing to conduct while the voltage across
the device is not reversed (forward-biased).

Thyristor
 In the normal "off" state, the device restricts current to the
leakage current.
 When the gate-to-cathode voltage exceeds a certain
threshold the device turns "on" and conducts current.
Modes of Operation:

SCR
 A silicon-controlled rectifier (or semiconductor-controlled rectifier) is a
four-layer solid state device that controls current.
 The name "silicon controlled rectifier" or SCR is General Electric's trade
name for a type of thyristor.
 An SCR consists of four layers of alternating P and N type semiconductor
materials.
 Silicon is used as the intrinsic semiconductor, to which the proper dopants
are added.

SC
R  The doping of PNPN will depend on the application of SCR, since its
characteristics are similar to those of the thyratron.

What is Android?
 Android is an open-source operating system which means that any
manufacturer can use it in their phones free of charge.
 It was built to be truly open.
 For example, an application can call upon any of the phone’s core
functionality such as making calls, sending text messages, or using the
camera.

Android
 Android is built on the open Linux Kernel.
 Furthermore, it utilizes a custom virtual machine that was designed to
optimize memory and hardware resources in a mobile environment.

LED Android
 Android is open source and Google releases the code under the Apache
License.
 This open-source code and permissive licensing allows the software to be
freely modified and distributed by device manufacturers, wireless carriers
and enthusiast developers.
 Additionally, Android has a large community of developers writing
applications ("apps") that extend the functionality of devices, written
primarily in a customized version of the Java programming language.

AC Controller
 MOC3051 can control the signal voltage transmitting from the
mocirocontroller to the TRIAC which isolates the AC and DC supply.

Working Principle
 To control AC power to a load by using firing angle control of thyristor.
 Efficiency of such power control is very high compared to any other
method.
 Remote operation is achieved by any smart Interface) based touch
screen operation.
 Comparator whose output is then fed to the microcontroller.
 The triggering control to a pair of SCRs through opto isolator interface.

Working Principle
 Finally the power is applied to the load through the SCRs in series.
 This project uses a microcontroller from 8051 family which is interfaced
through a Bluetooth device
 It receives signal from Android application de load.
 A lamp is used in place of an induction motor whose varying intensity
demonstrates the varying power to the motor.

Working Principle
 The varying power results in variation in speed of the motor.
 The project can be further enhanced by using direct 230 volt supply
instead of 12 volt AC to the bridge rectifier for achieving higher voltage
control for charging number of batteries in series.

Applications
 Low energy consumption.
 High thermal insulation.
 Superior performance.
 Long functional life.

Conclusion
 We have been discussing about project uses a microcontroller from 8051
family which is interfaced through a Bluetooth device, which receives signal
from Android application device for increasing or decreasing the AC power
to the load with LCD display. A lamp is used in place of an induction motor
whose varying intensity demonstrates the varying power to the motor.

Remote ac power control by android application with lcd display

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