We are gathering data about student posture while seated using different and key points on the seat and on the back of the chair, and also we can get information about how the subject leans back and forward. Using this information enhance the way we can define the emotional status of the student.
Hardware

This is a chair pad that can be placed in any regular chair. The pad covers the seat and the back of a chair. It has six pressure sensores distributed three in the seat and three in the back (right, middle and left). It also has an accelerometer that sense how the body leans.
Software

In order to use this hardware and get the information from it, our team developed a console application for Windows written in Java.

It is important to mention that this same application works for four different hardware: Skin Conductance Sensor, Posture Chair Sensor, Pressure Mouse Sensor and Pressure Guitar Sensor.
Installation
  1. Download the application.
  2. Unzip the file, and copy all the files into a new folder called "sensors".
  3. And you are done!
Using the system
  1. Before using the application, you need to physically connect all sensors to the computer, and find out in which port (COMM) it is connected.
  2. Open a Command window.
  3. Change to the "sensors" folder.
  4. Type CommonSensorsJ2E <output_file_name>. Where output_file_name is the name of the file where all data will be stored. This file will be stored on the "sensors" folder.
  5. The application prompt you to specify in which port is connected each sensor. In this case we need to find the port where the chair is connected. When it shows up in the screen type "chair", if there is listed a port where none sensor is connected just type "none".
  6. To stop recording data just press Ctrl + C.
  7. The output file will be in the same folder as the application is.
Description of the output file

The output file could be opened as CSV file, so it can be readed as plain text file or using some spreadsheet application such as Excel. If you run the programm just with the chair your file will have the following fields:

Field Description Values
Timestamp It is the timestamp (date and time) of the computer running the system. It could be used to synchronize the data with other inputs. The value is a combination of the date and time on the computer, with the following format "yymmddhhmmssSSS" (y - year, m - month, d - day, h - hour, m - minutes, s - seconds, S - milliseconds).
AccX The value of the X axis of the accelerometer. These values goes from 0 to XXX.
AccY The value of the Y axis of the accelerometer. These values goes from 0 to XXX.
rightSeat The value of the sensor positioned at the right of the Seat. The value of the sensor varies from 0 to 1024. Being 1024 the highest pressure.
middleSeat The value of the sensor positioned at the middle of the Seat. The value of the sensor varies from 0 to 1024. Being 1024 the highest pressure.
leftSeat The value of the sensor positioned at the left of the Seat. The value of the sensor varies from 0 to 1024. Being 1024 the highest pressure.
rightBack The value of the sensor positioned at the right of the Back. The value of the sensor varies from 0 to 1024. Being 1024 the highest pressure.
middleBack The value of the sensor positioned at the middle of the Back. The value of the sensor varies from 0 to 1024. Being 1024 the highest pressure.
leftBack The value of the sensor positioned at the left of the Back. The value of the sensor varies from 0 to 1024. Being 1024 the highest pressure.
Details about time rates
The information generated for these sensors is about one value every XXX millisec, in other words X values per second.
References