Posted to News on 23rd Apr 2015, 00:00
Wireless automatic Taekwondo scoring system uses LabVIEW
Researchers at the Asia Pacific University of Technology and Innovation set themselves the challenge of developing an automated Taekwondo scoring system with pressure sensors using low cost, readily available materials, and embedding them into the protective gear. They developed their solution using National Instruments LabVIEW to design the GUI, and constructed a pressure sensor using piezoresistive antistatic foam along with an Arduino Uno board to convert the output voltage from the interface circuit of the sensor and transmit it to the PC through XBee modules.
>Taekwondo competitions are judged by a referee, but at times, due to human error, points are inaccurately awarded and the game becomes biased. The concept of the automatic scoring solution was to solve this problem by automating the process of awarding points. The system is free from human interruption as well as human error. It can be used during a match and for training. Combatants can determine the minimum amount of force required while punching or kicking to score points. They also can discover their weak points to improve on them and determine the strength of their kicks or punches.
>The system includes pressure sensors fitted into the chest guard. These sensors are connected to an Arduino Uno board connected to an XBee wireless transmitter. The XBee wireless receiver module is connected to the laptop with an interface designed to display the scores. The system awards points based on the activation of the pressure sensors. Designer Rizwan Mohammed Elias says: "We designed the interface using the LabVIEW graphical development environment. LabVIEW was the ideal software for this application because it made the process of designing the interface easier.
>"The block diagram shows the basic components of the system," he continues. "The sensor is connected to an Arduino Uno board that is connected to an XBee wireless module that acts as the transmitter. The PC running the GUI designed using LabVIEW is connected to an XBee module (receiver) through USB." The interface displays the match time as well as the scores between the opponents. The opponents are represented as blue and red. The user can specify the match time and the threshold, which enables different weight classes to use the system. Lower weight class opponents use a lower threshold than the higher weight class opponents.
>Piezoresistive pressure sensors are used for the system. Their resistance modifies with changes in applied pressure. This change in resistance is converted to a change in voltage using a non-inverting amplifier circuit. The output voltage from the amplifier is fed to the analogue input of the Arduino Uno. The Arduino Uno converts the voltage to a 10-bit digital value. This value is sent wirelessly through an XBee module. Another XBee module connected to the serial port of the PC receives the data as a string. Before this data is processed, the system converts it to a number using the decimal-string-to number function. The converted value is then used for several processes including being compared to the threshold value set by the user. If it is found to be higher, three points are awarded. This process is repeated for both the red and blue teams until the game time elapses.
>The system can use the pressure value to plot a graph that shows the change in pressure with time to give a visual representation of the change in pressure. The reset button initialises the values of the time and sets the score to zero without stopping the VI. "The pressure sensors we developed have good accuracy and fast response," concluded Elias. "The interface we created using LabVIEW successfully receives and processes the data. Overall, we are pleased with the success of the system.
