LITERATURE REVIEW

In this part, we will discuss more about the components that are used in Development of Integrated Crops Management System (DICM). The main components for this project such as IR sensor, solenoid DC motor, DC gear motor, arduino and buzzer. This part is to enhance the knowledge of the student about the project. 

 Infra red sensor (IR sensor)

This sensor can be used for most indoor applications where no important ambient light is present. For simplicity, this sensor doesn't provide ambient light immunity, but a more complicated, ambient light ignoring sensor should be discussed in a coming article. However, this sensor can be used to measure the speed of object moving at a very high speed, like in industry or in tachometers. In such applications, ambient light ignoring sensor, which rely on sending 40 kHz pulsed signals cannot be used because there are time gaps between the pulses where the sensor is 'blind'...

The solution proposed doesn't contain any special components, like photo-diodes, photo-transistors, or IR receiver ICs, only a couple if IR-LEDs, an Op amp, a transistor and a couple of resistors. In need, as the title says, a standard IR led is used for the purpose of detection. Due to that fact, the circuit is extremely simple, and any novice electronics hobbyist can easily understand and build it. 

Figure 1: An infra red sensor

Solenoid DC motor

The Solenoids

Solenoids are actuators capable of linear motion. They can be electromechanical (AC/DC), hydraulic, or pneumatic driven and all operating on the same basic principles. Give it energy and it will produce a linear force. They are great for pushing buttons, hitting keys on a piano, valve operators, and even for jumping robots. DC solenoids operate on the same basic principles as a DC motor

Figure 2: Solenoid DC motor  

How solenoids work

Inside a solenoid is motor wire coiled in a special way. When an electric current was send through this wire (energized), a magnetic field is created. The inner shaft of a solenoid is a piston like cylinder made of iron or steel, called the plunger or slug (equivalent to an armature). The magnetic field then applies a force to this plunger, either attracting or repelling it. When the magnetic field is turned off, a spring then returns the plunger to its original state.

  

                        Figure 3: Inside of solenoid motor       Figure 4: Effect of solenoid motor 

DC gear motor

A gear motor is a type of electrical motor. Like all electrical motors, it uses the magnetism induced by an electrical current to rotate a rotor that is connected to a shaft. The energy transferred from the rotor to the shaft is then used to power a connected device. In a gear motor, the energy output is used to turn a series of gears in an integrated gear train.

Function 

In a gear motor, the magnetic current which can be produced by either permanent magnets or electromagnets turns gears that are either in a gear reduction unit or in an integrated gear box. A second shaft is connected to these gears. The result is that the gears greatly increase the amount of torque the motor is capable of producing while simultaneously slowing down the motor's output speed. The motor will not need to draw as much current to function and will move more slowly, but will provide greater torque.

Uses of gear motor

Gear motors are commonly used in conveyor-belt drives, home appliances, in handicap and platform lifts, medical and laboratory equipment, machine tools, packaging machinery and printing presses. A special type of gear motor, the servo motor, provides more power in a compact, precise fashion, and is used when a motor with a rapid, accurate response is needed.

Figure 5: DC gear motor

Arduino

An Arduino is a single-board micro-controller and a software suite for programming it. The hardware consists of a simple open hardware design for the controller with an Atmel AVR processor and on-board I/O support. The software consists of a standard programming language and the boot loader that runs on the board. Arduino hardware is programmed using a Wiring based language (syntax + libraries), similar to C++ with some simplifications and modifications, and a Processing based IDE.

An Arduino board consists of an 8-bit Atmel AVR  micro-controller with complementary components to facilitate programming and incorporation into other circuits. An important aspect of the Arduino is the standard way that connectors are exposed allowing the CPU board to be connected to a variety of interchangeable add-on modules (known as shields). Official Arduinos have used the megaAVR series of chips, specifically the ATmega8, ATmega168, ATmega328, and ATmega1280. Most boards include a 5-volt linear regulator and a 16 MHz crystal oscillator (or ceramic resonator in some variants), although some designs such as the LilyPad run at 8 MHz and dispense with the onboard voltage regulator due to specific form-factor restrictions. An Arduino's microcontroller is also pre-programmed with a bootloader that simplifies uploading of programs to the on-chip flash memory, compared with other devices that typically need an external chip programmer.

Figure 6: ATmega 328