We started by coding and testing the Bluetooth part. Although we successfully enabled the response function of Bluetooth, for unknown reasons, it often failed to respond to our commands. According to the method we studied before, the ranging method of Bluetooth components is distance = response time/2. But we soon realized a more serious problem. Even if we try to use two Bluetooth components to communicate with each other to confirm the distance between each other, this cannot tell the direction of the Arduino user (the holder of the other Bluetooth component). To this end, we proposed a feasible solution, placing a Bluetooth component in each of the four corners of the space to form a matrix. Use them to measure the relative positions of the robot and the token user in this space to confirm the direction. We asked Mr Ho and Tony about this. We got some bad news. Although Bluetooth devices have the advantage of a larger range, their ability to resist interference from obstacles is weak. This means that if our robot is obscured by shelves or people in the space we envision for supermarket shopping, it will lead to inaccurate ranging. In addition, the accuracy of the Bluetooth device we purchased cannot meet the needs of distance measurement, and advanced Bluetooth components are not only expensive but also have high operating requirements, which do not meet our requirements. Finally this idea ends here, RIP!
