Industrial greenhouses have automated control systems for climate, lighting, irrigation, ventilation and heating regulation using feedback sensors. Nowadays it is a trend to increase the measurement data amount as various additional IoT sensors are installed, thus the regulation becomes more precise, and due to available data, enables also new analytical features to create new control rules or strategies. This article focuses on PAR sensor development for such IoT sensor system, that will be used as main feedback signal to create lighting control strategy, same time increasing energy efficiency and reducing also costs. As artificial lighting energy consumption costs create 20-40% of total greenhouse costs, it is worth to have a more precise lighting control system, monitoring the energy crop obtains during the day from the sun, and then the missing amount (also period) of light energy then is provided by artificial lighting. First tests are performed in laboratory and industrial greenhouse of SIA “Latgales darzenu logistika” focusing on IoT based Photosynthetically Active Radiation measurements.