CA2 Report

New Fashion Media

 

 

 

 

 

CA2 Report                                                Andre Lim Jiande U058760H

 

We believe that in the near future, with the growing standard in the fashion industry, interactive media will be a integral part of clothes.  Clothing will be a better expression of our attitudes, emotions and needs.  As such, colour will be a key to these abilities of expression and to be able to control it will be a very big step.

 

Objective: To create a non-emissive colour changing material which displays passive colour change based on emotions, touch etc and to create a interface to control the colour changes.

 

Limitations: Non Emissive, Controllable, material must be flexible

 

Focus:  Our scope is limited to the displaying part of the entire concept ie, we do not have to care about the emotions/touch sensing.

 

Research Done:  Current technologies, advantages and disadvantages, colour-changing inks – photochromic, electrochromic, thermochromic, heating and cooling elements.  To make

 

Technology used: Thermochromic Ink.  After intensive research done, our team decided to employ use thermochromic ink after weighing the pros and cons of each method.  The use of a heating and cooling element – the Peltier module introduced by the previous fyp student will be used.

 

Method employed: To use a interface to control the temperature of a Peltier module which will in turn control the temperature applied to the shirt.  A matrix system is employed to attain a matrix grid control over the colour changing properties in order to achieve pixel display system like that of a LCD screen.

 
 

 

 

With our limitations in placed, this method is chosen as the best way and the most feasible way of implementing the concept.

 

Implementation Phases:

1) Research of various alternatives was done.  Pros and Cons of each method were compared.  Accessing the commercial viability of the entire concept and acceptance.

 

2) Research of thermochromic ink done. The limitations of thermochromic were accessed.  Concluding, we decided to employ a three colour change first.  Blue, red, green were used.

 

3) Purchase of Thermochromic Ink.  Trigger temperatures at 15, 31, 47 degree Celsius. Red – 15,  Green – 31,  Blue - 47

 

4) Experimenting and testing of the ink. A good balance of colour of retainer had to be achieved for optimum thermochromic properties.  Two alternatives method: layering the inks and complete mixture of the inks.  Complete mixture of ink was feasible while the other one was not.

 

5) Evaluating the Peltier module.  Accessing the viability of the previous fyp’s heating and cooling element.

 

6) Creating of the matrix system.  The use of a dual bridge driver to control the direction of current applied to the Peltier module for a particular grid.  (One direction will result in heating and the other will resulting in cooling).  5Vs relays are used to control which grid will be selected for colour change input.

 

7) Creating of a communication interface.  Serial communication is established between the PIC and the computer.  A RS232 cable and a max 233 was used to facilitate the serial communication between the two ports.  Input from the keyboard allowed us to select which grid we want to choose to heat or cool the system.

 

8)  Temperature feedback control system was researched on for better feedback to the heating system in order to achieve more accurate thermal control and therefore colour change using the TMPO4.

 

Problems analysis and challenges faced:

1) Firstly, when the matrix system was implemented, BJTs were initially used.  However, due to limitations on the limiting current in BJTs, it posed a problem and therefore relays were used instead.

 

2) Serial communication between the PIC and computer was done using C.  A lot of problems with the coding were faced just to initiate RX and TX communication due unstable currents. A max233 was subsequently used to resolve the problem.
 
 

The next step:

1)  To integrate the Peltier module effectively with the matrix system. The size of the Peltier module and the overspill heating and cooling effects of adjacent grids pose a problem for small pixel display.  Fine tuning has to be done in order to achieve optimum colour change which can be done using grid separation techniques.

 

2)  To do up a user friendly interface for pattern display on the shirt.  Program is mainly coded using C#.

 

Therefore, knowing clearly our ultimate aim, feasibility and our progressive steps, we look forward working towards achieving a commercially viable product.

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