The aim of this project was to produce an accurate, low cost CO detector. The use of a chemical sensor with a self testing feature made this product one of the best products of its kind on the market. The use of a small 8 bit micro and non-replaceable batteries to cover the sensors 5 year life expectancy, was quite a challenge. In addition to the sensor research, electronic and firmware design, Questek also developed much of the support equipment for testing and production.