# 9. Motor sizing and battery sizing - B-Division-2022-2023-Odd/Repo-04 GitHub Wiki

### Materials used and their specifications:

1. our model contains 12 clamps. weight of 12 clamps=120g

2. our model contains 2 linges. weight of 2 linges=32g

3. our model contains 36 screws with nuts and washers. Weight=15g Total mass mass=32+120+15=167g=0.167kg/cm

4. our model contain foam board and acrylic sheet.

density of foam board:1g/cm^3

density of acrylic sheet:1.185g/cm^3

### Motor sizing:

volume of arm: 15.242.540.6*2=46.45cm^3

volume of cuboid: =1651.6cm*3

volume of sphere: 2/3*pir^3 =16.74cm^3

We need two servo motors for the model, therefore motor sizing required for lifting the arms is :

volume of arm + volume of sphere = 46.45cm^3 + 16.74cm^3 = 63.19g/cm^3 = 0.063kg/cm^3

mass=rho*v

=63.19*1.185

=74.88g/cm

=0.074kg/cm

mass of a coin=6g=0.006kg

mass of 6 screws with nuts and washers=2.4g=0.0024kg

total mass=0.074+0.006+0.0024 =0.08kg/cm

F=m*r

F=0.08*15.24

F=1.21*1.5(safety factor)

F=1.81kg/cm

Therefore, we need SERVO MOTOR-TOWER PRO MG90S at 4.8V stall torque with operating voltage of 4.8-6.6V and stall current of 700mA.

Motor sizing required to eat the coin :

volume of cuboid/2=1651.6/2

=825.8g/cm^3

=0.825kg/cm^3

density of foam board:1g/cm^3=0.001kg/cm^3

mass=rho*v

=0.001*0.825

=0.00083kg/cm

Mass of 14 screws=5.83g=0.00583kg

Total mass=mass of cuboid+mass of 14 screws

=0.00083+0.00583

=0.0066kg/cm

F=m*r

=0.0066*20.32

=o.13*1.5(safety factor)

=0.19kg/cm

=1.8kg/cm

Therefore, we need SERVO MOTOR-TOWER PRO MG90S at 4.8V stall torque with operating voltage of 4.8-6.6V and stall current of 700mA.

### Battery sizing:

COMPONENTS USED AND THEIR SPECIFICATIONS:

1. Ultrasonic sensor:

Current requirement: 15mA

Voltage requirement: 5V

2. 16*2 character LCD display:

Current requirement: 1mA

Voltage requirement: 4.7-5.3V

3. Arduino mega 2560:

Current requirement: 40mA

Voltage requirement: 7-12V

4. 2no's Servo motor-Tower pro MG90S:

Current requirement: 700mA*2=1400mA

Voltage requirement: 4.8-6.6V

Total current requirement: 15mA+1mA+40mA+1400mA=1456mA=1.456A

Therefore, we need one 5v adapter for the servo motors and the LCD display and the power for ultrasonic sensor and LED bulb is supplied by the ultrasonic sensor.