2005 IRISH SCIENTIST YEAR BOOK

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Desmond College, Limerick
Claire Conaghan, Aine Mulcahy and Sean Liston
ICE: intelligent cat's eyes

Early in 2004, partly due to penalty points, we became aware of the amount of accidents leading to the injury and frequent death of numerous Irish people. Whilst some of this was attributable to speeding, more of it was apportioned to excessive speeds in unsuitable road conditions. If only there was a way of warning people to these conditions!

This problem led us to the possibility of designing something that would warn drivers to a deterioration of road conditions due to inclement weather, especially icy conditions. We quickly established that the current method of "Cats Eyes", whilst fantastic, had limitations, so we decided to concentrate our efforts on making an intelligent cat's eye, which we later christened I.C.E. for short.

In an effort to make cat's eyes intelligent we originally proposed to use a thermostat; when the temperature dropped, the reflective strips would change and thus refract a different colour light. We decided that whilst this would work in practice, the physical size of the cat's eye prohibited us from fitting the workings inside the existing footprint.

The eureka moment came whilst assisting in the minding of children during the summer. One of the children had a bowl that changed colour when heated and returned to normal when cooled. We quickly became aware of other similar uses of this type of heat sensitive material, such as indicators on batteries to indicate power levels and flexible thermometers used in medicine. Crystals refract different colours when exposed to a light source, similarly thermocromic ink, depending on its molecular structure, takes on a different colour depending on temperature. We carried out extensive testing on the material until we perfected the colour change.


By modifying the properties of a sample of thermochromic ink which we received from a UK manufacturer, we successfully managed to adhere it to the glass of the cat's eye. By diluting the ink we achieved a solution that changed colour to blue when temperatures dropped below freezing and returned to its normal trans-lucent state when the temperature increased.

Our next problem was how to apply the ink in such a way as to allow the light from the car to be reflected, several patterns and designs later we achieved the desired result. In addition to solving bonding problems, we overcame the problem of "light fastness", that is the propensity for items to lose their colour when exposed to natural sunlight.


Claire Conaghan, Team Leader, Eddie Wade, Cathaoirleach, Limerick Co. Council, Sean Liston and A�ne Mulcahy.

Claire Conaghan, Aine Mulcahy and Sean Liston entered their project in the Senior Group Section in the Technology Category at the EsatBT Young Scientist & Technology Exhibition in January 2005. They won one of the top prizes - Runner-up Group Award. They also won a Special Award sponsored by the Patents Office. Their teacher was Mr. Donal Enright.


This article was sponsored by the Patents Office