We Talkin’ About Practice

Bringing the practice straight to your door!

Brian Dong Hyun Kim

All about that user interface.

Sheen Lueh

The back-end gatekeeper.

Jason Yan

Hacks hardware together on the daily.


This project is a device designed to provide indoor practice of a variety of sports to all users. Using a collection of sensors assembled on a glove, this device sends fast real-time data from the motion of user’s swing to calculate projectile trajectory.

Competitive Analysis

Visual Sports Systems

It is a sport simulator that has an array of sensors that detect user motions and projects the ball movement onto a screen. Our product differs in that our cost will be significantly cheaper and it will be more portable and easy to use.

Sports Simulator

Sports simulator uses cameras and a shock proof screen to track the motion of a ball and simulate that from a projector. Our product differs in that we are able to use the product in a smaller space, as opposed to having to convert an entire room.


A sports enthusiast today would need a plethora of expensive and unwieldy equipment to accurately quantify and improve their ball-handling skills. Using our prototype system, an enthusiast will be able to effectively practice their skills on-to-go and at an affordable cost.


  • Sensors must be able to read any changes in hand flex to depict releasing of the projectile, and accurately read the force and change in angular rate to calculate direction and distance.
  • The glove will have an actuator that informs the user when the projectile trajectory has been terminated. The simulated model will be available shortly after.
  • Dive will be capable of use in any location given that the user’s cellular device is nearby and available.
  • The simulated model will provide the user the specific projectile trajectory relative to a hypothetical field, the distance from the user, and any change in direction of hand motion. The user will be able to input a desired target point to potentially hit before the swing to practice accuracy.
  • There will be a mobile application for the model, where the user can also input desired wind conditions (or simulate current wind conditions from a weather forecast), as well as projectile mass and weight to simulate the ball of the user’s choice.
  • Bluetooth will be used for data transmission.


  • Portability. The device will be very low powered and easily rechargeable, or have the option to use batteries.
  • Timing. Device will display simulated output within 30 seconds.


Flex Sensor 2.2”, SEN-10264 ROHS

  • Cost: $7.95
  • Flat Resistance: 10K Ohms ±30%
  • Power Rating: 0.5 Watts continuous; 1 Watt Peak
  • Bend Resistance: minimum 2 times greater than the flat resistance at 180° pinch bend
  • Adjustable Buffer: a potentiometer can be added to the circuit to adjust the sensitivity range
  • Variable Deflection Threshold Switch: an op amp is used and outputs either high or low depending on the voltage of the inverting input. In this way you can use the flex sensor as a switch without going through a microcontroller
  • Temperature Range: -35°C to +80°C

9 Degrees of Freedom - Razor IMU SEN-10736 ROHS

  • Cost: $74.95
  • ITG-3200 (MEMS triple-axis gyro), ADXL345 (triple-axis accelerometer), and HMC5883L (triple-axis magnetometer)
  • The outputs of all sensors are processed by an on-board ATmega328 and output over a serial interface
  • Comes programmed with the 8MHz Arduino bootloader (stk500v1)
  • Operates at 3.3VDC
  • LiPo batteries are an excellent power supply choice
  • Output pins match up with FTDI Basic Breakout, Bluetooth Mate, XBee Explorer

Arduino Fio DEV-10116 ROHS

  • Cost: $24.95
  • ATmega328V running at 8MHz
  • Arduino Bootloader
  • XBee socket
  • Lithium Polymer battery compatible
  • MCP73831T LiPo Charger
  • Reset button
  • On/Off Switch
  • Status/Charge/RSSI LEDs

SparkFun Bluetooth Modem - BlueSMiRF Silver WRL-12577 ROHS

  • Cost: $24.95
  • v6.15 Firmware
  • Extremely small radio - 0.15x0.6x1.9"
  • Very robust link both in integrity and transmission distance (18m)
  • Hardy frequency hopping scheme - operates in harsh RF environments like WiFi, 802.11g, and Zigbee
  • Encrypted connection
  • Frequency: 2.402~2.480 GHz
  • Operating Voltage: 3.3V-6V
  • Serial communications: 2400-115200bps
  • Operating Temperature: -40 ~ +70C
  • Built-in antenna


Eclipse - Java IDE

  • Programming Language: Java
  • Allows for virtually unlimited customization and extension
  • Eclipse Marketplace

Android Studio IDE

  • Programming Language: Java
  • The official Android IDE
  • Intelligent code editor
  • Code templates and GitHub integration
  • Multi-screen app development
  • Virtual devices for all shapes and sizes
  • Android builds evolved, with Gradle


  • Programming Language: Digitalocean API
  • Simple cloud hosting service
  • Tools to help us scale our product
  • Floating IPs
  • SSD Hard Drives
  • KVM Virtualization
  • IPv6 Support



Used to connect ICs on a single board. The bus has one clock and one data line


Wireless communication protocol. Arduino on glove communicates with mobile phone via Bluetooth


Serial peripheral interface is a 4-wire full duplex bus. The bus has a clock, transmit, receive, and select line


A convenient way to transmit complex data structures