Figure 14

Figure 14: PCB design using EAGLE s/w

Solar Battery Charger Circuit Advantages:
• Adjustable output voltage
• Circuit is simple and inexpensive.
• Circuit uses commonly available components.
• Zero battery discharge when no sunlight on the solar panel.

Figure 15: Solar circuit on PCB

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Cart Modelling: Catia V5 software is used for 3D modelling of cart .Catia V5 is used to
convert raw idea into actual model.

Figure 16: Bluetooth controlled cart
Bluetooth controlled cart is controlled by using Android smartphone instead of any other method like keys, gesture or remote control etc. to control the cart in forward, backward, left and right directions. So here android smartphone is used as transmitting device and Bluetooth module placed in cart is used as receiver. Android smartphone will transmit command using its in-built Bluetooth to cart so that it can move in the required direction like moving forward, reverse, turning left, turning right and stop, thus making it a smart agricultural system.
• Arduino UNO
• DC Motors(100rpm)
• Bluetooth module HC-05
• Motor Driver L293D
• 12 Volt Lead-acid Battery and 9 volt battery
• Battery Connector
• Cart chassis
Bluetooth Module
HC-05 Bluetooth module consists two things a Bluetooth serial interface module and a Bluetooth adaptor. Bluetooth serial module is used for converting serial port to Bluetooth.
How to operate Bluetooth module?
We directly use the Bluetooth module HC-05. Default baud rate of new Bluetooth module is 9600 bps. We just need to connect RX and TX to controller i.e. Arduino Uno or serial converter and give 5 volt dc regulated power supply to module.
Bluetooth module has a ‘master mode’ and a ‘slave mode’. User can set either of the modes by using some AT commands. Even user can set module’s setting by using AT command. Here is some commands uses are given:
First of all user needs to enter AT mode with 38400 bps baud rate by pressing EN key at Bluetooth module or by giving HIGH level at EN pin. Note: all commands should ends with \r\n (0x0d and 0x0a) or ENTER KEY from keyboard.
After it if you send AT to module then module will respond with OK
AT ? Test Command
AT+ROLE=0 ? Slave Mode select
AT+ROLE=1 ? Master Mode select
AT+NAME=xyz ? Set Bluetooth Name
AT+PSWD=xyz ? Set Password
AT+UART=,, ? set Baud rate
Eg. AT+UART=9600,0,0
Pin Description of accelerometer
1. STATE ? Open
2. RX ? Serial receiving pin
3. TX ? Serial transmitting pin
4. GND ? ground
5. VCC ? +5volt dc
6. EN ? to enter in AT mode
Working Explanation
The cart has two dc motors at its front and rear side. Combination of side motors is used for giving direction to cart means turning left or right side while all four motors are for driving the cart in forward and backward direction. A Bluetooth module is used to receive command from android smartphone and Arduino UNO is used for controlling the whole system.
Bluetooth controlled cart moves according to the key clicked on the android Bluetooth mobile app. To run this project first we need to download Bluetooth app form Google play store. We can use suitable Bluetooth controller app from controller.
After installing app you need to open it and then search Bluetooth device and select desired Bluetooth device. And then configure keys. Here in this project we have used Bluetooth controller app.
1. Download and install Bluetooth Controller.
2. Turned ON mobile Bluetooth.
3. Now open Bluetooth controller app
4. Press scan
5. Select desired Bluetooth device
6. Set keys by pressing set keys on screen and then press ok..
When we click ‘forward key’ in Bluetooth controller app then cart start moving in forward direction and moving continues forward until next command comes, similarly for the ‘backward key’.
When we click ‘left key’ in Bluetooth controller app then cart start moving in ‘left direction’ and moving continues left until next command comes. In this condition front side motor turns front side wheels in left direction and rear motor runs in forward direction, similarly for the ‘right key’.
And by clicking stop key we can stop the cart.
Bluetooth controlled cart is shown in above figure. A Motor driver is connected to arduino to run the cart. Motor driver’s input pins 2, 7, 10 and 15 are connected to arduino’s digital pin number 12, 11, 10 and 9 respectively. Here we have used two DC motors to driver cart in which two motors of one side are connected at output pin of motor driver 3 and 6 and another side motors are connected at 11 and 14. A 12V battery is used to power the motor driver for driving motors which uses solar panel to charge itself. Bluetooth module’s Rx and Tx pins are directly connected at Tx and Rx of Arduino. And Vcc and ground pin of Bluetooth module is connected at +5 volt and gnd of Arduino. And a 9 volt battery is used for power the circuit at Arduino’s Vin pin.
Clicked key in Bluetooth controller app
Output for front side motor to give direction
Output for rear side motor to move forward or reverse direction
Key M11 M12 M21 M22 Direction
Stop 0 0 0 0 Stop
Forward 0 0 0 1 Forward
Backward 0 0 1 0 Backward
Right 1 0 0 1 Right
left 0 1 0 1 Left
Table 4: Motor driver using Bluetooth controls
5. Results
1. The Infrared sensor sensed the strip on the cart wheel and indicated accordingly.
2. The servo motor rotates at a uniform speed when no input is given through the keypad. According to the inputs received from the IR sensor and the keypad (1 or 2 key is pressed).
3. Servo rotates at an angle of 45 degrees beginning from 0 to 180 and then returns back to 0 degree.
4. When keypad 1 is pressed the seeds fall with a delay of 1 second that is they fall at 29.3 cms away from each other. When keypad 2 is pressed they fall at 58.6 cms.
5. The moisture sensor senses the moisture of the soil which is indicated on the LCD in percentage.
6. If the moisture percentage is less than 50 % the irrigation pump starts fueling water to the field. It continues to water for 3 seconds then again checks the moisture level and takes decision accordingly.
7. A bluetooth module is used to control the cart, which allows it to move forward, backward and sideways.
8. Solar panels are used to store energy in rechargeable battery which powers the system.

6. Conclusion/ Future scope
A smart bluetooth controlled cart along with sensors powered and controlled by Arduino UNO was built so as to look into the different varied needs of the farming industry. The system is powered by solar panels which is a green, non polluting, energy efficient source of energy. Different agricultural systems like sower, moisture level measurement and irrigation was brought together in a single system.
The system can use further new inventions and ideas. More new farming techniques can be further integrated like soil nutrient measurements and more range of distances for different seed varieties. Other conventional sources sources of energy can be used where solar energy is not always dependable like water, biogas or wind harvesting methods.
The water pump can also be controlled wirelessly by bluetooth which helps to decrease human labour. Also the seed sower can be combined with a digger that digs upto a certain depth for placement of seeds.