# Smart Trash Bin Model Design and Future for Smart City
## 3 Model Design  
### A Design of the IoT-Based Smart Trash Bin  
The proposed smart trash bin that was adopted is shown in Figure 2. As for the mechanism, a label indicating the type of recyclable material is scanned by the camera attached to the slot. If it confirms that the trash is recyclable, the trash cover will be opened to drop the trash down into the storage. If there is no label to be read, the type of trash will be identified by the spectroscope and image classification and stored based on the resulting calculation value. Depending on its value, when the trash approaches the proximity sensor attached to each recycling bin slot, the slot opens and enters the space. The degree of trash bin filling can be checked through the disposition sensor. When the trash bin is 80% full, it sends an alarm to the central server using a communication module. The operation of the Smart Trash Bin starts with the Check Status and Send Alarm processes. First, when a trash bin user approaches the trash bin, the trash bin checks its own status and then sends an alarm to the server, or shows a message to the user about its status. When it is decided whether to put the trash in, the trash bin will proceed with recycling label recognition through photography. In the absence of label recognition, spectroscopy and image classification tasks determine the type of trash. After that, separate collection is carried out according to the type of trash. Figure 3 shows the Flowchart of Smart Trash Bin operation processes. Figure 2: A design of the Smart Trash Bin. Figure 4 shows the pseudocode of the Smart Trash Bin and a series of operational processes. According to the pseudocode, one must check the status of the trash bin before putting the trash in to see if it can receive the trash. It sends an alarm to the server, telling the user that the trash bin is full. If there is space, one can put the trash in the trash bin. First, make sure that there is a recycling label on the trash. As soon as the label is confirmed, it enters the separation collection process, and if not, it checks the type of trash through spectroscopic and image classification. If the type of trash is confirmed through this process, it will determine whether it is recyclable and collect it separated into recyclable waste (paper, plastic, cans, glass, and vinyl) and non-recyclable trash. Figure 3: A flowchart of Smart Trash Bin operation processes. First, we reviewed the adequacy of our methods of distinguishing the materials with each sensor after selecting five companies in the ROK. The problem was that it was difficult to find suitable sensors for the applications in our separation/collection system. We plan to apply an image processing technique and a spectroscope for the system implementation instead of the sensors that exhibit a high rate of error. Similar to human eyes, the image processing technique distinguishes various situations and objects by using a camera linked to the computer. This technique is developing rapidly, as artificial intelligence has become one of its supporting elements. Second, the merit of this technique is that the images and words (specified as \"Can\", \"Plastic\", \"Vinyl\", or \"Glass\") on the trash labels can be recognized with a low-cost camera. These will be used to determine what the materials are made of, with relatively high accuracy and efficiency. If this system is combined with a low-level spectroscope, which usually demonstrates a low reading accuracy, better results can be obtained, while maintaining a moderate cost. Figures 5 and 6 show the image processing system + spectroscope. Spectroscopes have been mostly used in the field of science, but their application in the IoT-based trash bins was hardly considered in the ROK because of their high prices. However, the prices are becoming lower over time and they are currently used for various purposes and products. For instance, they are being used by banks, airport immigration, and customs to check counterfeit bills, fake passports, and other imitation products.