# Development of a Wireless System to Control a Trombe Wall for Poultry Brooding
## 2 Materials and Methods  
It is intended to implement a class A LoRa device in order to collect data from temperature sensors located in the Trombe Wall and send them to The Things Network platform, which acts as a server. There, they are transferred to the ThingSpeak integration and with the associated applications, which are be generated a response that are be sent to the microcontroller, based on the these work in the following way: if a received temperature value is higher, equal to or lower than a predefined value on React, this triggers a temperature value (Figure 3). These applications are React and ThingHTTP (this last one has to be an integration in The Things Network in order to let the data arrive at the server from ThingSpeak) and prefigured action [27]. In this case, that action is the ThingHTTP using the POST method to publish in the TTN server a response that fits the situation, which schedules the deliver of that feedback to the microcontroller, which acts on the actuators (XPS boards) [28]. Figure 4 is a block diagram that represents the whole system, step by step. The Trombe wall system used for poultry brooding is based on the one studied in previous research works [5, 6, 7]. An automation and control system of the air vents and external shading device operating modes was also proposed to improve the Trombe wall thermal performance and guarantee specific indoor temperature conditions, without user's intervention on the system management. Data acquired in this experimental study were analyzed and used as a support of the work here presented. The mechanical system defined in the referred work to perform the automation and control of the air vents was also considered [8]. However, this control system makes decisions locally, while the one designed in the presented work communicates with a server where those measures are taken. This is an advantage given the possibility to interfere on decisions and consult data remotely. As normally in this circumstances, the poultry structure is not in the range of WiFi; therefore, LoRa is used to communicate with a gateway, which redirects data via Ethernet to the server and vice versa. The mechanical system defined in [8] allows the indoor temperature fluctuation control with the opening/closing of the ventilation system throughout the use of covering boards made by extruded polystyrene (XPS)--defined as shutters in Figure 3--with rotating hinges controlled by servos. XPS was used given its lightweight and thermal properties that contribute to avoiding heat transfer through the air vents. It also contributes to an easy movement of the mechanical system. The chosen servos were the \"Futaba S3003\" to the rotating system and the DHT21 sensors to the temperature measures. At the time of the achievement of the experimental study and based on research work developed by [PERSON] [29], it was defined that a maximum advantage of the Trombe wall can be achieved based on the temperature differential between the air gap and the internal environment. This is made to maximize heat accumulation in the air gap before opening the XPS boards, allowing faster heat transfer to the internal space under study. In a previous research work, different scenarios were studied to optimize the temperature range values that support the working algorithm of the automation and control system. Different iterations led to the conclusion that the most suitable way to reach the indoor comfort temperatures would be to consider the temperature range between the internal environment (Ti) and the air gap (Tcam).The limit values established for the opening/closing of the air vents were considered effective for increasing the air gap greenhouse effect and heat storage before the opening of the air vents, so that the room would be heated more quickly and higher temperatures can be achieved. If that difference is higher than 15 \({}^{\circ}\)C, the air vents should be opened and if it is lower than 10 \({}^{\circ}\)C, they should be closed [8], as seen in Table 4.