Integrator and Sensors for Measuring Photosynthetically Active Radiation and Temperature in the Field

(1) Designs are described for sensors, integrators and a readout device which together measure temperature (or day-degrees) and photosynthetically active radiation (or short-wave radiation in the 300 to 3000 nm waveband). (2) The equipment is cheap to produce (?15 to ?18) and has a low electrical power requirement (3 mW at 20 'C). (3) The integrators may be adjusted to measure temperature or irradiance above set thresholds.