# Development of a Multifunctional Unmanned Boat Platform for Aquaculture Automation
## 2 Complete Machine Structure and Working Principle
### Platform Structure and Details
#### 2.1.2 Environmental Data Acquisition Module  
Water quality monitoring in aquaculture is a key component to ensure the healthy growth of cultured animals. Traditional water quality monitoring usually relies on manual sampling and laboratory analysis, which is time-consuming and laborious, and difficult to obtain data in real time. The environmental data acquisition module of the unmanned boat can realize real-time and continuous water quality monitoring, providing timely and accurate information for aquaculture management. In addition, the modularized design [16; 17; 18] makes the platform easy to expand and maintain, adapting to the needs of different farms. The environmental data acquisition module is mainly developed based on the NodeMCU development board, carrying water temperature monitoring sensors, pH monitoring sensors, TDS sensors, and so on, as shown in Figure 4.  
Figure 3: UBP function module. Figure 2: Hardware structure. (1) DS18B20 Digital Water Temperature Sensor  
The DS18B20 Digital Water Temperature Sensor is a commonly used digital temperature sensor based on single bus communication technology. It features an internal integration of the temperature sensing elements and analog-to-digital conversion circuitry, capable of converting temperature changes into digital signal output. Its core is a negative temperature coefficient thermistor. As the temperature changes, the resistance value varies, and this change is converted into a digital signal through internal circuitry processing. The specific object is shown in Figure 4a. (2) PH4502C pH Sensor  
The PH4502C pH electrode sensor is mainly composed of two parts: the glass membrane electrode and the reference electrode. The glass membrane electrode contains a sensitive membrane that is selective to hydrogen ions. When the electrode is immersed in a solution, the sensitive membrane reacts with hydrogen ions in the solution, generating a potential difference proportional to the hydrogen ion concentration (i.e., pH value). This potential difference is converted into a current or voltage signal. The signal is then amplified and processed through electronic circuits, ultimately outputting an electrical signal that corresponds to the pH value of the solution. The object is shown in Figure 4b. (3) TDS turbidity sensor  
The TDS turbidity sensor is mainly used to measure the conductivity of the water solution to indirectly calculate the TDS value. The more ions dissolved in the water, the stronger its conductivity. The sensor has two electrodes, when the sensor probe is placed into the water, a stable AC voltage is applied at both ends of the electrodes, and the ions in the solution move directionally under the action of the electric field, thus generating a current. According to [PERSON]'s law, the resistance or conductivity of the solution can be calculated by measuring the current. Since there is a certain proportionality between the TDS value and the conductivity, the TDS value can be further calculated. The physical object is shown in Figure 4c. Figure 4: Sensors. (**a**) DS18B20 digital water temperature sensor; (**b**) PH4502C pH sensor; (**c**) TDS turbidity sensor; (**d**) NodeMCU development board. The NodeMCU is an open source internet of things (IoT) development board based on the ESP8266 chip [19; 20], which combines Wi-Fi functionality with a programmable microcontroller to enable developers to rapidly build and deploy IoT projects. Raspberry Pi type development boards consume too much power, while ordinary microcontrollers lack native Wi-Fi capabilities. Therefore, in this paper, we choose the NodeMCU development board with lower power consumption and native Wi-Fi capability. At the heart of the development board is the ESP8266, which supports the IEEE 802.11 b/g/n standard, is capable of communicating over the 2.4 GHz band, and features low power consumption for battery-powered devices.