A low-cost fluorescence temperature sensor using the decay-time principle has been constructed, using a millimetre size probe element, a dedicated microprocessor and simple logic circuitry with LED excitation of the material. Results in the region from -50 to +200 degrees C have been reported with a approximately +or-2 degrees C accuracy using Q100 neodymium glass and comparisons made with commercially available sensors. Extension of the work to higher temperature measurement is discussed.