Apparatus for measuring multi-wavelength transmittance using learned led temperature compensation model

A submersible apparatus for measuring multiple wavelengths of light transmittance through a liquid, the apparatus comprising:

• multiple light emitting diodes (LEDs) of different peak output wavelengths;
• a light detector for detecting an intensity of light;
• a structure surrounding the LEDs and detector wherein said structure allows the apparatus to be submersed in a liquid wherein the structure is shaped to allow a volume of liquid to be between the LEDs and detector such that the amount of light able to transmit through the liquid from the LEDs is detected by the detector;
• an optical unit that collects light from the LEDs and directs it though the liquid without the need for moving parts;
• at least one temperature sensor mounted near the LEDs as well as a temperature sensor mounted near the light detector to record the temperature of the LEDs and detector during transmission measurements;
• a microprocessor programmed to:
• a) control the LEDs such that the LEDs can be energized one at a time or in sub-groups of the total number of LEDs, and subsequently measure via the detector the amount of light for a specific LED or sub-group of LEDs able to transmit though the liquid;
• b) use a predictive model applied to data derived from the temperature sensors light detector to compensate the transmittance measurements for the effects of temperature on raw light output of the LEDs as well as temperature related detector drift.