# Miyazaki Vermin Repulsion Robot and Its Adjustable Acousto-Optic Stimulus Generation Scheme
## 2 Development of MiVeReR Prototype
### Four Main Units of MiVeReR  
To achieve the expulsion task, MiVeReR is primarily composed of four main units: a visual sensing unit, a control unit, an actuation unit, and an acousto-optic signal generation (AOSG) unit. Figure 2 illustrates the control architecture of MiVeReR to describe individual units. First, the visual sensing unit observes the surroundings and assesses whether there is an intruder, such as a wild animal. In this unit, a web camera (ELP 1080P 200 HDUSB,  
Figure 1: Conceptual illustration of MiVeReR capable of generating changeable acousto-optic signals. Here, MiVeReR generates different acousto-optic signals while focalizing on the mouse at times \(t-1\) and \(t\) after its detection at \(t-2\). Figure 2: Illustration for the control architecture of MiVeReR. Ailipu Technology Co., Ltd., Shenzhen, China) is employed to observe the surroundings. In practice, the web camera allows MiVReR to monitor intruders day and night. Three consecutive image data are obtained at interval \(T\) using the camera. The output of this unit at time \(t\) is the reconstituted data \(f_{t,i}\), where \(i=1,2,3\), by referring to the robot's coordinate system. The details on the process of \(f_{t,i}\) in the unit are described in the next section. Second, the control unit examines whether there exists an intruder in the \(f_{t,i}\) data obtained by the visual sensing unit to compute the location of the intruder and track its movements. To perform complex operations, Raspberry Pi4 Model-B 4 GB is used as the main controller and coded based on the Python 3.11.9 and Open CV 4.9.0 software environment [35]. This unit comprises three functions: identification, mapping, and tracking (Figure 2). To begin, the identification function determines the existence of an intruder from \(f_{t,i}\). This function outputs a two-alternative answer such as existence and nonexistence. The computation results are then used in the next functions. The details on the computational process are explained in the next section. Next, the mapping function obtains the location of the intruder. Finally, based on the obtained location, the tracking function generates pulse width modulation (PWM) signals using a tracking-function controller (Arduino Mega 2560, Arduino Co., Ltd., Lombardia, Italy) with a motor controller (MDV 2 \(\times\) 2A DC Motor Controller (L298N), Zhiwei Robotics Corp., Shanghai, China) to enable the robot to focus on the intruder. Using the coordinates of the desired target, the distance to the target is calculated, and adequate PWM signals are generated. Third, the actuation unit moves toward the position provided by the control unit. In this unit, two types of rotation motions in the yaw and roll directions are realized. For horizontal rotation generation, a DC motor (TG-47G-SG-5-HA, TSUKASA Co., Ltd., Tokyo, Japan) is used to achieve significant torque gains. The mechanical structure is explained in the next subsection. For vertical rotation generation, a servo motor (HS-M7990 TH, Hitec Multiplex Japan, Inc., Tokyo, Japan) is used. The encoder signals from the two motors are input to the tracking function of the control unit. Fourth, the AOSG unit generates repellent signals, focused on the target intruder. The repellent signal used in this unit at time \(t\) is defined as \(S_{f}(t)=\{s_{a}(t),s_{o}(t)\}\), where \(s_{a}(t)\) and \(s_{o}(t)\) denote sound and light signals, respectively. In practice, to generate \(S_{f}(t)\), two types of hardware devices are combined. First \(s_{a}(t)\) is realized using a speaker (T440 II, Pioneer Corp., Tokyo, Japan). Second, \(s_{o}(t)\) generated using a light-emitting diode (LED) flashlight (X004, Alonefine Co., Ltd., Shenzhen, China) provides four-color lights: red, green, blue, and white. Based on these hardware specifications, the generable frequency range of \(s_{a}(t)\) is from 5000 Hz to 20,000 Hz. Specifically, \(s_{a}(t)\) with different frequencies can be generated by the variations of 1000 Hz within the range.