Team MRIIC:

Dr. Umesh Dutta

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Texas Instruments University Program

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Published July 2, 2019 © GPL3+

Table Tennis Ball Smasher Machine

Enhance your table tennis skills with our ball smasher machine, which provides easy control via an Android app.

AdvancedFull instructions provided3 days2,103

Things used in this project

Hardware components

Texas Instruments MSP-EXP430G2 MSP430 LaunchPad

HC-05 Bluetooth Module

SparkFun Dual H-Bridge motor drivers L298

DC motor (generic)

Software apps and online services

Texas Instruments Energia

MIT App Inventor 2

Hand tools and fabrication machines

3D Printer (generic)

Story

Aim:

To design an Android app-controlled table tennis ball smasher machine using TI MSP430G2553 LaunchPad module.

Components Used:

· MSP430G2553 LaunchPad

· L298 motor driver

· HC-05 Bluetooth module

· 12V DC motors

Working

It is a prototype which is designed to be used by the table tennis players so that they can practice and enhance their skills. It is operated with the help of a mobile application. First of all, the user needs to establish a connection between the mobile application and the bluetooth module. Afterwards, the user needs to turn the device ON so that data can be sent serially to the MSP module. Then comes the textbox which takes an integer value(ranging from 0 to 255) from the user as an input. When the ‘SEND’ button present on the app is pressed, communication enables and data is sent to the msp 430 via bluetooth. After receiving the data, the msp over-writes the value of the pulse width of the motor in the analogwrite function.

Input Value is proportional to Pulse Width which in turn is proportional to Speed of the motor

As the value of the Pulse Width changes, the motor driver commands the motors to rotate at different rpm as per the value. If the user wants to stop the motors, they just have to press the stop button on the app and the motor gets stopped in the real time.

Figure of Merits:

· Easy to operate

· Speed as well as angle of projection can be altered

· Can be quite useful for the beginners to practice

· Can produce different types of ball movements like spin, fast pace, slow pace.

· Lightweight

· Easily mobile

· Operates in real-time

App Layout

Android App Layout

Block Code

MIT App Inventor Block Code

Demo Video

Table Tennis Ball Smasher

Code

Ball Smasher DC Motor Control

int a;  // declare an integer a to store incoming serial data

void setup() 
{
  // put your setup code here, to run once:

  // enable 6 msp pins as output
  pinMode(11,OUTPUT); 
  pinMode(12,OUTPUT);
  pinMode(13,OUTPUT);
  pinMode(9,OUTPUT);
  pinMode(8,OUTPUT);
  pinMode(7,OUTPUT);
  
  Serial.begin(9600);  // enable serial communication

  // initially all the pins are at low state
  digitalWrite(12,LOW);
  digitalWrite(11,LOW);
  digitalWrite(7,LOW);
  digitalWrite(8,LOW);
}

void loop() 
{
  // put your main code here, to run repeatedly: 
  if (Serial.available()>0)  // when the incoming byte > 0
  {
    a=Serial.parseInt();  // read the bit and store in ‘a’
    
    if ((a>1) && (a<256))
    {
      digitalWrite(12,HIGH);
      digitalWrite(11,LOW);
      analogWrite(13,a);
      digitalWrite(7,HIGH);
      digitalWrite(8,LOW);
      analogWrite(9,a);
      Serial.println(a);  // Serially prints the value of a
    } 
    else if(a==1) 
    {
      digitalWrite(12,LOW);
      digitalWrite(11,LOW);
      analogWrite(13,a);
      digitalWrite(7,LOW);
      digitalWrite(8,LOW);
      analogWrite(9,a);
      Serial.println(a);  // Serially prints the value of a
    } 
    else
    {
      Serial.println(a);  // Serially prints the value of a
    }
    delay(1000);
  }
}