Hardware

Components

A. Arduino Duemilanove 328 Board was the main microcontroller to drive this kinetic dress.

B. Heart Rate Interface, which receives heart rate data from the transmitter from the wearer was connected to the Ardino board via 2 analog input pins It must be installed to face the transmitter to detect signals.

C. LilyPad Accelerometer measured the body movement of the wearer, delivered data to Arduino board by 3 analog input pins.

D. Servo Motors driven the kinetic system. Its digital input cable was connected to digital output pins of Arduino board.

E. Batteries Holder supplied power to Ardino board, Heart Rate Interface, Accelerometer, and Servo Motors.

F. Transmitter sensed hear rate from the human body when worn on the chest. It detected heart rate when wearer was sweating. The sensor only worked when it got wet.

Circuits

The servo motor was easy to control, and only needed to connect its digital input cable to the digital output pins of Arduino Board. 10 servo motors took 10 digital pins from pin 2 to pin 11 on Arduino Board. The RX and TX pin on Heart Rate Board connected to analog pin 4 and 5 on the Arduino board through 4.7kOhm resistor for protection. X, Y, Z axis pins on accelerometer were connected to analog input pins on Arduino Board as well. All the connections must be steady to maintain the operation of the dress, even when people were worry about.

Power

The Heart Rate Interface needed up to 5.5 voltages power supply. The operation of servo motors needed a higher power supply. They could run from 3 to 7.2 voltages. The batteries holder took 4 AAA/AA batteries. And each AAA/AA battery was 1.5 voltages. Four of them would supply 6 voltages power. However, 6 voltages were over the maximum limitation of power supply to Heart Rate Interface. Rechargeable AAA/AA battery involved 1.2 voltages. (See Figure 3.29.) Therefore, Four pieces rechargeable AAA/AA batteries could supply around 4.8 voltages power to Heart Rate Interface.

Software

Arduino

The Arduino program was used in this project. When Arduino board was connecting to the computer, the serial monitor could print the data which sensed from the heart rate board and accelerometer. It could help designer to adjust the setting of the accelerometer and test the operation of motors. The output data could also provide support to point out the problem when the accidents happened to hardware parts. For instance, if right hand side motors on the dress was not working. The output data showed input value from accelerometer was zero. That meant the connection had problems between analog pins of accelerometer and Arduino board. When the left hand side was wrong, needed to check whether the transmitter was worn correctly, or the Heart Rate Board connected properly to the Arduino board.

The arduino code (Julio, 2008) of communicating Heart Rate Interface (HRMI) to Arduino Board was written by Dan Julio, www.danjuliodesigns.com. (Version 1.1 12/28/2008)

Technical Details

Here was a section of the output data from the Arduino serial monitor. Different colour output data showed three different situations of the vertical movements of the dress. “acc” meant the input values of Y-axis of Accelerometer. “hr” was the heart rate beats. They also were mapped to drive number of motors to move vertically. “Dir is true” determined motors ran the looping from top to the bottom. “Dir is false” told the motors to loop from bottom to the top.