## 3 Materials and Methods
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Component** & **Manufacturer** & **No. of Pieces** & **Price (EUR)** \\ \hline Raspberry Pi 5 & Raspberry Pi Ltd., Pencoed, UK & 1 & 89.9 \\ \hline Raspberry Pi display & Raspberry Pi Ltd., Pencoed, UK & 1 & 69.8 \\ \hline Pi5 27 W power supply with USB-C & Raspberry Pi Ltd., Pencoed, UK & 1 & 13.4 \\ \hline NEMA 23 stepper motors & MOONS’, Shanghai, China & 2 & 36 \\ \hline Motor drivers & Toshiba, Tokyo, Japan & 2 & 16 \\ \hline Elgato Neo Facecam & Corsair Gaming, Munich, Germany & 1 & 92.1 \\ \hline Sandisk microSDXC Memory Card & Western Digital, Milpitas, CA, USA & 1 & 35.6 \\ \hline Case for Raspberry Pi 5 & Official Raspberry Pi Foundation, Cambridge, UK & 1 & 12 \\ \hline Plexiglass separators & EuroPlastics, Wroclaw, Poland & 18 & 30.5 \\ \hline Plywood & Koskisen Group, Jarvenpaa, Finland & 3 & 45.25 \\ \hline Flaps & Hettich, Kirchlengern, Germany & 2 & 9.2 \\ \hline Recycling compartment &
\begin{tabular}{c} Waste Management Solutions Ltd., \\ Birmingham, UK \\ \end{tabular} & 4 & 15.5 \\ \hline Cable & Nexans, Paris, France & 5 & 19.2 \\ \hline Joint components & Blum, Höchst, Austria & 16 & 20.55 \\ \hline Other components & - & 20 & 58 \\ \hline TOTAL & - & - & 563 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Price of RBin components. The physical structure of the prototype is built using plexiglass separators and materials for housing the components. These materials contribute to the overall cost of the prototype, which totals 563 EUR for the components used in the prototype. This breakdown reflects the key expenses associated with assembling the functional prototype for the RBin system, excluding any potential additional costs related to shipping or miscellaneous items. Moreover, the physical construction materials could be cheaper in other parts of the world, bringing the total cost of the prototype and the final product down. The main challenge of the RBin is represented by the software infrastructure, which must perform the following actions in the shortest time possible:  
* The camera captures the image;
* The image is sent to the classification service or algorithm;
* A response is received from the algorithm regarding the identified category;
* Motors are activated according to the identified category. Figure 2 presents the block diagram of the category identification procedure. This flowchart describes the procedure for controlling the two NEMA23 stepper motors (M1 and M2) in response to a service's classification result. The procedure involves acquiring an image from the Elgato Neo Faccam, sending it for processing, and then controlling the motors based on the classification result. * Start. The process begins by acquiring an image from the Elgato Neo Faccam;
* Send Image to Service. The captured image is sent to a service for classification;
* Service Response. The service processes the image and returns a classification result, referred to as glass, plastic, cardboard, and metal;
* Decision on Category. The returned category is evaluated. Based on the result, the motors will be controlled;
* Category 1. If the category equals 1, the stepper motor M1 rotates to the left, M1 returns to its starting point, and the stepper motor 2 (M2) rotates to the front and  
Figure 2: RBin software block diagram. then returns to its starting point, as the object identified as metal was placed in the corresponding compartment;
* Category 2. If the category equals 2, M1 rotates to the right, M1 returns to the starting point, M2 rotates to the front, and M2 returns to its starting point. The second category is glass;
* Category 3. The plastic category is identified if the category equals 3. For plastic object identification, the M1 stepper motor rotates to the left, M1 returns to the starting point, M2 rotates to the back, and M2 returns to the starting point;
* Category 4. If the category equals 4, M1 rotates to the right, M1 returns to the starting point, M2 rotates to the back, and M2 returns to the starting point.