Bluetooth grass cutter

1. JSS ACADAMY OF TECHNICALEDUCATION DEPARTMENT OF
MECHANICAL ENGINEERING
DESIGN AND FARBRICATION OF BLUETOOTH CONTROLLED GRASS
CUTTER

2. INDEX
1. Introduction
2. Literature Survey
3. Problem Definition
4. Objectives
5. Methodology
6. Working Principle
7. Expected Outcome
8. References

3. ABSTARCT
•The ultimate aim of this project is to design, develop and fabricate of grass cutter machine.
•The design is optimized with respect to size and shape. The functional and unfunctional areas required
material thickness is adopted.
•Less weight and high strength wheels were used for slow motion.
•This project methodology is initially identified the problems faced by framers and money spend to cut
the grass.
•To these issues, this project has designed, developed and fabricated the machine low cost Bluetooth
operated cutting operation.
•The design concept was made by using auto cad and cero software (Pro-E). The Complete 3D digital
model was done and validated the design.
•The same 3D model is converted into 2D manufacturing drawings by using AutoCAD. Later, optimized
machine was fabricated by required material thickness and proper manufacturing approach. The
fabricated machine was tested and works effectively and efficiently.

4. INTRODUCTION
• The machine 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. 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 Bluetooth controlled grass cutting machine which can be operated through
android phone. This research implements the android operated grass cutting machine. This system establishes
connection with android phone using Bluetooth. This machine’s motion includes following motions:- forward, backward,
left turn, right turn and grass cutter on/off . All these motions are controlled by android application. This machine
is operated by using 12V 7.5AH battery.

5. • Intro cont….

6. LITERATURE SURVEY

7. PROBLEM STATEMENT
• The lawn machine we use today is an automatic lawn mower that makes it easy for humans. But
there are still some disadvantages to the lawn. Some of the auto lawn mowers that use the motor
will cause difficulty in starting the engine. It also takes a long time to turn on or start. So this
problem will be affect to lawn mower user to use it because it will waste time.
• Then, another problem is the lawn mowers nowadays mostly use fuel. A costs for having a lawn
mower using fuel is a bit expensive compared to ordinary lawn mowers. So, here we can reduce
the cost because the mechanical lawn mower does not use any fuel and it can save your money.
This is because, not everyone is able to have a lawn mower using the engine.

9. Objective
 To study present grass cutters and their mechanisms.
 To design and fabricate a Compact chassis which can accommodate all functional elements.
 To select and implant efficient blades which can cut through tough grasses.
 To select suitable battery pack and solar panel for the machine.
 To make the machine easy to operate by incorporating Bluetooth module.
 To study the performance of the machine and to record the results.
• There will be a minimum weight and compact in size.
• Reduce the overall cost. To make the machine economical.
• To create a machine that made the cutting work, easy and quick.
• To reduce human efforts and to save time
• To operate the system wirelessly.

10. METHODOLOGY
LITERATURE SURVEY
DESIGN AND
FABRICATION DETAILS
MATERIAL SELECTION
FABRICATION
TESTING

11. WORKING
• The vast majority of robotic lawn mowers tackle the task utilizing a
"random" mowing system.
• Basically the machine bounces around on the lawn until it hits the
boundary wire limiting the working area, then changes heading until it
hits the wire again.
• The working principle of the lawn mower is to provide a high speed
rotation to the blades, which aids in cutting the grass through
generated kinetic energy.

12. SPECIFICATION
Operation: Cutting
• BATTERY – 12V
DC MOTOR:
• DC Motor is used to rotate the wheel which is used to move the machine from one place to another.
• Following are the specification of DC Motor:
• Speed:100 RPM DC Motor
• Current :7 Amp
• Voltage :12 V

14. Block diagram

15. Design Calculation
•Torque required to cut the unwanted plants in the field:
•Torque:
•T=F×L
•In the case of the force exerted is due to the mass being accelerated by gravity:
•T=(mass[kg]×g)×radius[m]
•where g=9.81m𝑠−2
•Lift a 0.3kg mass using a 140mm diameter cutting blade. We can find the torque load created by the
•mass using equation T[Nm]=mass[kg]×gyradius
•=0.3 X 9.81 X 0.07
•= 0.206 Nm

16. •Total force produced by the model
•. Wheel = 0.356×4=1.424×9.81=13.96N
•. Frame = 11.955 ×9.81=117.2N
• DC motor =1.3×3=3.9× 9.81=38.26N
• Y-Bearing =0.5× 4 =2× 9.81 =19.62N
•Total= 189.04 N
•Sprocket radius = 50mm
•Torque on D.C motor to drive the vehicle
•T=F×L
•T= 189.04 ×50
•T=9452 Nmm
•T= 9.452 Nm

17. •CUTTING OPERATION:
•Force required to cut grass
•F=𝜏×𝐴
•F=39×1.130
• F=44.107N
•Torque required
•T = F×L
•=44.107×0.02
•T= 0.882 N-m

18. Power consumption of grass cutting machine
•Input power
•P=V×I
•=7.2×12
•=86.4 Watts
•Output power
•P = 2×π×N×T60
•P = 2×𝜋×500×0.88260 P= 46.18 watts

19. DISCUSSIONS AND CONCLUSION
• This prototype can be further modified for commercial use by
increasing its efficiency and reducing its cost. This project is has many
advantages when compared to a conventional lawn mower, for
instance: No fuel cost, no pollution and no fuel residue, less wear and
tear because of less number of moving components, and the devices
can be operated wirelessly. The device can be easily handled and
reduces burden on humans.

20. ADVANTAGES
 It uses green energy and is eco friendly.
 Since it can be interfaced with Android devices it makes its operation very easy.
 It can cut through tough grasses very easily.
 The height of the grass to be trimmed can be adjusted.
 It is affordable and requires very less maintenance .
•

21. DISADVANTAGES
 It is only suitable for moderate operation time. If we desire a longer
operation time ,we should go with Lithium polymer batteries which
makes it costlier.
 It is only suitable for small/medium sized grasses.