The consumer proposition is a personal monitor that helps you manage your exposure to sun, to avoid burning while still getting enough for a tan.
Technically it has a very special UV detector whose spectral response is a close match to the spectral sensitivity of the skin to UVB and UVA.
We developed the UV detector from scratch and it remains the most accurate low cost detector. It uses UV fluorescence of an organic dye as a solid solution on a transparent polymer to define the spectral sensitivity. Using total internal reflection and careful optical design, high rejection of unwanted wavelengths is achieved.
A low cost MCU operates an integrating ADC circuit (again, very low cost) to measure the photocurrent from the sensor which is typically 10nA. All of this has to work from a 1.5V button cell for a year!
The MCU keeps track of daily exposure and, from the user's skin sensitivity setting and suncream SPF setting, calculates the allowable remaining exposure. Knowing the time of day and the typical variation of UV intensity as the sun rises and falls, a prediction is made of how long it will take to achieve the allowable UV dose.
Development activities:
We also developed a second version that was smaller, cheaper and had more functions
Sunwatch is not a current product, but for more information, contact: Saitek Industries