Android Controlled Solar based Grass Cutter Robot

— Manual grass cutting requires man power, time and it may create non-uniform structure of grass height. Hence to avoid all these issues it is essential to create a system which can cut the grass without any human involvement. This research implements the grass cutting robot which has battery which can be charged by solar energy. This robot can be operated using android phone. This system can be created with minimum cost as compared to other existing systems. This is rugged, durable and maintenance free. This system is pollution free due to the use of solar energy to charge the battery.


INTRODUCTION
The automation is useful at various stages of human life. The beautiful evenly cut grass increases the beauteousness of any hotel, house, park, meeting hall etc. Hence uniform grass cutting is important to maintain the prestige of any house or hotel. The manual grass cutting is possible using human being but it usually consumes time and energy of human being. Also the manual grass cutting is inefficient and many time results in non-uniform structure of grass. Hence to avoid all these issues it is better to use automated grass cutting robot machine which can be operated through android phone.
This research implements the android operated grass cutting robot. This system establishes connection with android phone using Bluetooth. This robots motion includes following motions forward, backward, left turn, right turn and grass cutter on/off. All these motions are controlled by android application. This robot is operated by using 12V 7.5AH battery. To charge this battery solar panel is connected above the battery.
Many researchers have proposed a similar design of solar based grass cutting robot. Firas B. Ismail et al. [1] implemented a design in which the blades of cutter are placed at the middle of four wheels of robot. This will creates disturbance during the grass cutting process. If the size of grass is larger, this will stop the wheel and hence this system cannot be used in a efficient manner. Bincy Abraham et al. [2] and Mallikarjun Mudda et al. [3] proposed a similar system of grass cutting robot. But this system cannot control by android smart phone. It has ultrasonic sensor which can detects the obstacle. This system automatically changes its path if the sensor senses any obstacle. Also this system does not contain four wheels. Hence sometimes it creates a problem of balancing in real time working scenario. Rishabh Gupta et al. [4] published a survey paper on solar based grass cutting robot. They had explained the various similar systems and their pros and cons. Sagar V. Palve et al. [5] implemented a similar system but this paper failed to show the actual model of the system.

A. Material
This system uses following material and components, i) Arduino with AT mega 328P microcontroller Arduino is an open-source embedded system platform platform. This research uses Arduino platform with ATmega328P microcontroller. This microcontroller has 28 pins and it is cheaper and efficient as compared to other microcontrollers. Any new C++ language code can be first tested in arduino-1.6.7-windows software. After verifying this code, it can be loaded into the Arduino platform using simple USB cable connected between PC and Arduino kit. The figure 1 below shows the Arduino IDE kit along with ATmega328P microcontroller. ii) LCD Display This research uses 16 by 2 LCD (Liquid Crystal Display) screen to display the direction of movement of this system. It also shows the ON and OFF status of Grass Cutter. This is a preferable module over seven segment and multi segment LED modules. This is because it is economical and it can show any special and custom character, animations and so on. This module can show 16 characters on each line and it has 2 such lines. Each character is on this LCD module is displayed in 5*7 pixel matrix. This LCD consists of Command Register to store the commands provided to this module. The Data Register in LCD module is used to store the data displayed on LCD display. Figure 2 below shows the 16*2 LCD module.

iii) Bluetooth Module
This research uses an Arduino, HC-06 bluetooth module to transfer the commands from android smart phone to the system. This HC-06 bluetooth module is mounted on the system along with some relays. Initially user connects its smart phone with this module. After a successful connection user can provide the desired direction change command to the system from maximum 10-meter distance. Also, user can switch ON and OFF the grass cutter through its mobile using the android application.
HC-06 bluetooth module is mainly used for short-range wireless connectivity. This is economical and durable module as compared to other existing bluetooth modules. Figure 3 below shows the HC-06 bluetooth module.  The DC motor in this system is connected with analog output pin of ATmega328P microcontroller. But this microcontroller can produces maximum 5V of DC output voltage. The DC motor connected with this system requires 12V DC input voltage to operate. Hence L293D motor driver IC is connected between microcontroller output pin and DC motor input. This IC acts as a current amplifier. It takes low current signal from microcontroller and after amplification provides high current signal to DC motor. This high current signal is useful to drive the DC motor. L293D consist of two inbuilt H-bridge driver circuits. Simultaneous operation of two DC motors is possible in common mode of this IC. Input logic at pins 2 and 7 and 10 and 15 controls the operation of two motors. To stop the first motor input logic 00 is used. Logic 11 is used to stop the other motor. Logic 01 and 10 will the motor clockwise and anticlockwise directions, respectively. Pin 1 and 9 are enable pins for two connected motors. To start this motors the enable pin of this motor must be high. The figure 5 below shows the motor driver IC L239D.

vii) Solar Panel
This system uses 12V, 10-Watt solar panel. It has aluminum frame and its surface is made up with tampered glass material. This panel is consists of mono crystalline silicon. This panel is compact, lightweight and economical as compared to other existing panels of similar rating. Figure 6 below shows the solar panel.

B. Methods
This research uses DC 12V 7.5AH battery supply to operate whole system. This battery is connected with solar panel. Hence solar energy is used to charge this battery. This system has 4 DC motors to which 4 wheels are connected and the blades for grass cutting are connected at the front side of this system. To operate this system the connection must be established between this system and android smart phone.
Both these are connected using Bluetooth. After the successful connection the user can operate this system using android application installed on smart phone. User can switch ON and OFF the grass cutter. Also, he can move this grass cutter in vertical and horizontal direction. The figure 7 below shows the complete system.    As shown in figure 9 above, initially the 12 V battery supply needed to start. This supply will be converted into 5V DC supply using voltage regulator. This 5V supply will be provided to microcontroller. The Bluetooth module needed to be started and connected to the android smart phone. Once the connection is established between the smart phone and the system, user can move this system in vertical and horizontal direction using android application in smart phone. User will start the grass cutter to cut the grass of desired location. After completing grass cutting task, user will switch OFF the grass cutter using android smart phone. Then the main system can be switched OFF by disconnecting the 12V battery supply to the system. V. CONCLUSION This research shows the implementation of smart phone operated grass cutter. This grass cutter can be operated using android smart phone within a 10 meter range. The user can perform horizontal and vertical movement of grass cutter using android application in smart phone. This system uses 12V 7.5AH lead acid battery. This battery can be charge by solar energy. To charge this battery the 12V, 10Watt solar panel is connected with this system. This system is cheaper, rugged and durable. With the use of this system human efforts for grass cutting are highly minimized. Also, manual grass cutting can create non-uniform grass size. But with the use of this system the grass cutting is uniform, and one can use this system to cut the grass of any playground.

VI. FUNDING
This research is self-funded. The author of this paper invested the complete amount to create this system.