# Energy-Efficient IoT-Based Light Control System in Smart Indoor Agriculture
## 2 Literature Review  
Smart indoor agriculture has recently attracted significant attention thanks to its ability to produce high-quality crops using fewer resources [17]. Artificial grow lights represent the key component of indoor agriculture; they play the critical role of providing light energy needed by plants for their growth and development processes [28; 29]. Nevertheless, controlling the grow lights manually can be imprecise, time-consuming, and laborious, especially in large production facilities containing multiple products in different developmental stages. In this case, the automation of light control and its remote operation from a server become a necessity [30]. Furthermore, the advantages of automation and remote control appear in plant factories where fine crops are produced all year round in controlled cultivation environments [31]. As previously mentioned, using the latest technologies to make the agricultural field more efficient and \"smarter\" appears to be a very promising solution to the challenges of resource depletion and increasing demand [17; 30]. Moreover, converting usual agricultural production to an indoor process where the growth conditions are controlled is expected to reduce the environmental impacts arising from farming practices and protect the crop from diseases, pests, and bad weather [18; 28]. It will also enable us to exploit non-arable lands in the areas covered by snow, rocks, or sand in indoor agricultural production to cover the food demand in these areas and reduce importation costs. However, indoor farming facilities suffer from the high energy consumption problem, and this energy is consumed in the management of the indoor growth conditions [32; 33]. State of the art contributions in indoor farming are mostly focused on finding solutions to this energy consumption problem [34; 35; 33]. In this article, we propose to continue in the same line by presenting an energy-efficient method based on IoT to remotely control the grow lights in indoor production facilities. Several studies have explored the use of IoT technologies in smart agriculture, and general reviews about the different contributions, challenges, and research directions in this field have been proposed by [5; 6; 20; 21; 36; 37]. Furthermore, many applications of IoT in the agricultural field can be found in the literature ranging from controlling tasks like irrigation [38], fertilization [39], harvesting [10], and other operations [8; 24] to plant growth monitoring tasks [40; 41], farm management systems [42; 43], indoor farming systems [44; 45; 46; 47], and the management of the food production chain [48]. The widespread use of IoT in agriculture is a result of its ability in data handling, its easy installation, and its decreasing cost. Moreover, many adaptations of existing IoT technologies to agricultural applications have been proposed to improve, for instance, data handling [49; 50; 51], the routing protocol [52; 53; 54], and energy efficiency [49; 55]. The automatic grow light control problem was investigated by many researchers. As a result, different solutions were proposed such as a digital control system based on the PI (proportional integral) controller of the PWM signal presented in [56], a grow light control method for aeroponic systems based on random forest classification and sensor fusion described in [57], a control method combining grow lights and natural light that turns the lights on and off whenever natural light is not sufficient [58; 59], a hybrid control method to control the PWM signal of LED grow lights [60], and a pulse lighting control method presented in [61] to find the best light exposure durations for plants in indoor farming. In brief, various methods to automatically control the grow lights were proposed for the goal of effectively managing lighting conditions and improving the yields and product quality.