CONTROL OF IRRIGATION PUMP THROUGH GSM TECHNOLOGY
CONTENTS
S.No. / Contents / Page1. / Abbreviations
2. / Figures locations
3. / Introduction
4. . / Block diagram
5. / Block diagram Explanation
6. / Schematic
7. / Schematic Explanation (pin to pin connectivity)
8. / Hardware components
a. Microcontroller (max 50 pages)
b. MAX 232
c. Power Supply
d. GSM
e. soil
f. dc motor
g. LCD
9. / Circuit Description
10. / Software components
a. About Keil
b. Embedded ‘C’
11. / Source Code / OUTSIDE
12. / Conclusion or Synopsis
13. / Bibliography
ABBREVIATIONS
Symbol / NameACC / Accumulator
B / B register
PSW / Program status word
SP / Stack pointer
DPTR / Data pointer 2 bytes
DPL / Low byte
DPH / High byte
P0 / Port0
P1 / Port1
P2 / Port2
P3 / Port3
IP / Interrupt priority control
IE / Interrupt enable control
TMOD / Timer/counter mode control
TCON / Timer/counter control
T2CON / Timer/counter 2 control
T2MOD / Timer/counter mode2 control
TH0 / Timer/counter 0high byte
TL0 / Timer/counter 0 low byte
TH1 / Timer/counter 1 high byte
TL1 / Timer/counter 1 low byte
TH2 / Timer/counter 2 high byte
TL2 / Timer/counter 2 low byte
SCON / Serial control
SBUF / Serial data buffer
PCON / Power control
FIGURES LOCATIONS
S.no Title Page no
1. Block diagram
2 Schematic diagram
3 Block diagram of controller
4 Memory types
5 Pin diagram of AT89c51
6 Serial communication
7 Keypad
8 Block diagram of LCD
9 Pin diagram of LCD
10 Power supply diagram
INTRODUCTION
Microchip has positioned itself to target the motor control market, where our advanced designs, progressive process technology and industry leading product performance enables us to deliver decidedly superior performance over our competitors, which includes the best of the industry. These products are positioned to provide a complete product solution for embedded control applications found throughout the consumer, automotive and industrial control markets. Microchip products are meeting the unique design requirements of the motion control embedded applications.
EMBEDDED SYSTEM:
An embedded system is a special-purpose system in which the computer is completely encapsulated by or dedicated to the device or system it controls. Unlike a general-purpose computer, such as a personal computer, an embedded system performs one or a few predefined tasks, usually with very specific requirements. Since the system is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost of the product. Embedded systems are often mass-produced, benefiting from economies of scale.
Personal digital assistants (PDAs) or handheld computers are generally considered embedded devices because of the nature of their hardware design, even though they are more expandable in software terms. This line of definition continues to blur as devices expand. With the introduction of the OQO Model 2 with the Windows XP operating system and ports such as a USB port — both features usually belong to "general purpose computers", — the line of nomenclature blurs even more.
Physically, embedded systems ranges from portable devices such as digital watches and MP3 players, to large stationary installations like traffic lights, factory controllers, or the systems controlling nuclear power plants.
In terms of complexity embedded systems can range from very simple with a single microcontroller chip, to very complex with multiple units, peripherals and networks mounted inside a large chassis or enclosure.
Examples of Embedded Systems:
· Avionics, such as inertial guidance systems, flight control hardware/software and other integrated systems in aircraft and missiles
· Cellular telephones and telephone switches
· Engine controllers and antilock brake controllers for automobiles
· Home automation products, such as thermostats, air conditioners, sprinklers, and security monitoring systems
· Handheld calculators
· Handheld computers
· Household appliances, including microwave ovens, washing machines, television sets, DVD players and recorders
· Medical equipment
· Personal digital assistant
· Videogame consoles
· Computer peripherals such as routers and printers.
· Industrial controllers for remote machine operation.
CROP FIELD SECTION:
BLOCK DIAGRAM EXPLANATION:
This Project mainly consists of Power Supply section, Microcontroller section, GSM, MAX 232, motor, LCD, soil.
Power Supply Section:
This section is meant for supplying Power to all the sections mentioned above. It basically consists of a Transformer to step down the 230V ac to 9V ac followed by diodes. Here diodes are used to rectify the ac to dc. After rectification the obtained rippled dc is filtered using a capacitor Filter. A positive voltage regulator is used to regulate the obtained dc voltage. But here in this project two power supplies are used one is meant to supply operating voltage for Microcontroller and the other is to supply control voltage for Motors.
Microcontroller (8052):
In this project work the micro-controller is playing a major role. Micro-controllers were originally used as components in complicated process-control systems. However, because of their small size and low price, Micro-controllers are now also being used in regulators for individual control loops. In several areas Micro-controllers are now outperforming their analog counterparts and are cheaper as well.
The purpose of this project work is to present control theory that is relevant to the analysis and design of Micro-controller system with an emphasis on basic concept and ideas. It is assumed that a Microcontroller with reasonable software is available for computations and simulations so that many tedious details can be left to the Microcontroller. The control system design is also carried out up to the stage of implementation in the form of controller programs in assembly language OR in C-Language
MAX 232 Sections:
The microcontroller can communicate with the serial devices using its single Serial Port. The logic levels at which this serial port operates is TTL logics. But some of the serial devices operate at RS 232 Logic levels. For example PC and GSM etc. So in order to communicate the Microcontroller with either GSM modem or PC, a mismatch between the Logic levels occurs. In order to avoid this mismatch, in other words to match the Logic levels, a Serial driver is used. And MAX 232 is a Serial Line Driver used to establish communication between microcontroller and PC (or GSM)
LCD Display Section:
This section is basically meant to show up the status of the project. This project makes use of Liquid Crystal Display to display / prompt for necessary information.
GSM modem Section:
This section consists of a GSM modem. The modem will communicate with microcontroller using serial communication. The modem is interfaced to microcontroller using MAX 232, a serial driver.
DC Motor:
DC motor is an output for this project. And DC motor is connected to microcontroller. And this motor controlled by the microcontroller with the respective inputs given by us. Its speed will be varied according to the speed set by the switches.
SCHEMATIC:
SCHEMATIC DESCRIPTION:
Firstly, the required operating voltage for Microcontroller 89S52 is 5V. Hence the 5V D.C. power supply is needed by the same. This regulated 5V is generated by first stepping down the 230V to 18V by the step down transformer.
In the both the Power supplies the step downed a.c. voltage is being rectified by the Bridge Rectifier. The diodes used are 1N4007. The rectified a.c voltage is now filtered using a ‘C’ filter. Now the rectified, filtered D.C. voltage is fed to the Voltage Regulator. This voltage regulator allows us to have a Regulated Voltage. In Power supply given to Microcontroller 5V is generated using 7805 and in other two power supply 12V is generated using 7812. The rectified; filtered and regulated voltage is again filtered for ripples using an electrolytic capacitor 100μF. Now the output from the first section is fed to 40th pin of 89S52 microcontroller to supply operating voltage and from other power supply to circuitry.
The microcontroller 89S52 with Pull up resistors at Port0 and crystal oscillator of 11.0592 MHz crystal in conjunction with couple of capacitors of is placed at 18th & 19th pins of 89S52 to make it work (execute) properly.
Port 0:
P0 is connected to the data pins of the LCD.
P2.5, P2.6, P2.7 are connected to control pins of the LCD.
PORT 2:
DC motor is connected to the port P2.1.
Soil is connected to the port P2.0.
Port 3:
GSm is connected to the port P3.0 & P3.1.
20th is connected to GROUND
40th is connected to Vcc
HARDWARE COMPONENTS:
The Hardware components used in this project are
ü Regulated Power Supplies
ü Microcontroller
ü MAX 232
ü GSM
ü LCD
ü Motor
ü soil
REGULATED POWER SUPPLY
7.0 Description
A variable regulated power supply, also called a variable bench power supply, is one where you can continuously adjust the output voltage to your requirements. Varying the output of the power supply is the recommended way to test a project after having double checked parts placement against circuit drawings and the parts placement guide.
This type of regulation is ideal for having a simple variable bench power supply. Actually this is quite important because one of the first projects a hobbyist should undertake is the construction of a variable regulated power supply. While a dedicated supply is quite handy e.g. 5V or 12V, it's much handier to have a variable supply on hand, especially for testing.
Most digital logic circuits and processors need a 5-volt power supply. To use these parts we need to build a regulated 5-volt source. Usually you start with an unregulated power supply ranging from 9 volts to 24 volts DC (A 12 volt power supply is included with the beginner kit and the Microcontroller. To make a 5 volt power supply, we use a LM7805 voltage regulator IC (Integrated Circuit). The IC is shown below.
FIG 7.1
The LM7805 is simple to use. You simply connect the positive lead of your unregulated DC power supply (anything from 9VDC to 24VDC) to the Input pin, connect the negative lead to the Common pin and then when you turn on the power, you get a 5 volt supply from the Output pin.
7.1 Circuit features
Brief description of operation: Gives out well regulated +5V output, output current capability of 100 mA
Circuit protection: Built-in overheating protection shuts down output when regulator IC gets too hot
Circuit complexity: Very simple and easy to build
Circuit performance: Very stable +5V output voltage, reliable operation
Availability of components: Easy to get, uses only very common basic components
Design testing: Based on datasheet example circuit, I have used this circuit successfully as part of many electronics projects
Applications: Part of electronics devices, small laboratory power supply
Power supply voltage: Unregulated DC 8-18V power supply
Power supply current: Needed output current + 5 mA
Component costs: Few dollars for the electronics components + the input transformer cost.
FIG 7.2 Full-wave Rectifier:
Full wave rectifier circuit is shown below. the transformer secondary has a centre-tap and each half give voltage of Vm. In each half there is one diode i.e. D1 and D2.the load resistance Rl is common to both halves.
This can be seen to comprise of two half-wave circuits. on the positive half cycle, when the point is +ve w.r.tB,theDiode D1 conducts and current i1 flows through Rl. During this half cycle, the point C is -ve w.r.t.point B and hence the diode D2 does not conduct. Therefore i2=0.
On the negative half cycle the point C is +ve w.r.t. point B. hence the diode D2 conducts and current i2 flows through RL. During this half cycle. The point A is –ve w.r.t.point B and hence the diode D1 does not conduct. Therefore i1=0
Fig.(b) and (c) shows the waveforms of currents i1 and i2 .since both i1 and i2 flow through the load RL, the current i through RL is i= i1+i2, which is obtained by adding the two waveform and is shown in fig(d)
Fig 7.3: the current waveforms of full wave rectifier
Advantages and disadvantages of full wave Rectifier:
(a) amount of ripple is much lower(r=0.482)as compared to half wave (r=1.21).
(b) Rectification efficiency is high (n=0.812)
(c) T.U.F is better (= 0.693) then that of half wave (=0.287).
(d) No problem of core saturation.
(e) Requires centre-tapped secondary of the transformer
Comparison of rectifier circuits:
Parameter / Type of RectifierHalf wave full wave bridge
Number of diodes /
1 /
2 /
3
PIV of diodes /
Vm /
2Vm /
Vm
Secondary voltage
(rms) /
V /
V-0-V /
V
Secondary voltage /
Vm /
V-0-V /
Vm
D.C output voltage /
Vm/ /
2Vm/ /
2Vm/
Vdc,at
no-load /
0.318Vm /
0.636Vm / 0.636Vm
Ripple factor /
1.21 /
0.482 /
0.482
Ripple
frequency /
f /
2f /
2f
Rectification
efficiency /
0.406 /
0.812 /
0.812
Transformer
Utilization
Factor(TUF) /
0.287 / 0.693 / 0.812
Capacitor Filter:
We have seen that the ripple content in the rectified output of half wave rectifier is 121% or that of full-wave or bridge rectifier or bridge rectifier is 48% such high percentages of ripples is not acceptable for most of the applications. Ripples can be removed by one of the following methods of filtering:
(a) A capacitor, in parallel to the load, provides a easier by –pass for the ripples voltage though it due to low impedance
At ripple frequency and leave the d.c.to appears the load.
(b) An inductor, in series with the load, prevents the passage of the ripple current (due to high impedance at ripple frequency) while allowing the d.c (due to low resistance to d.c)
(c) various combinations of capacitor and inductor,such as L-section filter section filter, multiple section filter etc. which make use of both the properties mentioned in (a) and
(b) Above.
Two cases of capacitor filter, one applied on half wave rectifier and another with full wave rectifier.
Full-wave Rectifier with capacitor filter:
Fig 4(a) shows the circuit diagram, with a full wave rectifier comprising of a center-tapped secondary winding and two diodes. All the analysis given in this section are also valid for a bridge rectifier, which also gives full-wave rectification. The filter capacitor C is connected in parallel with load resistance RL.