Remote Touchscreen-Controlled Defense Turret Senior Design Documentation Courtney Mann, Brad Clymer, Szu-yu Huang Group 11
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Another consideration is that the rangefinder must interface with the system processer, so that the gathered data can be translated into commands for the orientation of the turret. This will most likely involve a USB connection to the processor, and may incur some additional programming as well, in which case OpenCV may be utilized.
The system was to have a wide range of components. Table 3 summarizes the expected peak power requirements for the turret portion of the system, since the charging of the user interface will not be relevant during times of operation. Table : Power Requirements of Individual Components 
Since these components will require large amounts of current (and therefore power) at any given moment, the system will require either a large battery (which will inhibit transport) or the use of AC from a generator or wall outlet (which will limit installation location and make the project susceptible to interruptions of service from the power grid). The Arduino is normally powered by an AC adaptor which outputs 9V DC. Laser pointers – most notably the model which the group initially selected – are typically powered by two AA batteries, which are 1.5V cells in series. Thus, a 3V DC adaptor, properly wired, could serve as a suitable power supply for this device. Additionally, the servos will be controlled by the Arduino, but this device does not supply nearly enough current to operate them, so they will need some form of driver board to act as a buffer between the Arduino and the servos. This board could easily run on an 18v, 2A AC adaptor. The above specifications strongly suggested that AC should be the power source of choice for the project.
The housing for the project was constrained by requirements of durability, portability, accessibility, and visibility. In terms of durability, it needed to be able to withstand the torque applied by the servos to the armature, as well as frequent transport and disassembly. Since the project would be carried from workspace to workspace, portability would be a high priority. Since very few engineering projects work on their first attempt, the device needed to be easily accessible to alteration. Also, the group was advised early on that during the final evaluation of the project, the parties performing the evaluation would be very interested in seeing the inner workings of the device, so it should be visible. To address the durability requirement, a material with a strong tensile strength but low brittleness was required. This material would require tolerance of .121 kg-m torque resulting from the operation of the servos rotating at maximum speed, as well as the weight of the armature, which the group estimated would be in the range of 3 kg. For scalability, it was determined that, in case there needed to be a larger firing device – such as a heavy paintball gun – added later, there should be higher weight and torque tolerances. Also, this material would need to balance the attributes of having enough weight to counterweight the motion of the turret rotation, but not too much to interfere with portability. This portability would be achieved by a marriage between the use of a lightweight-enough material, and casters that allowed it to be rolled. The casters would be mounted through the base, and they would need to be high enough quality to handle repeated placements on the ground; this was a concern because members of the group had previously worked with music equipment, and noticed that casters for such equipment wear out prior to any other elements of the design. Accessibility was of primary concern both because of the necessity for the project to be worked on after it would be initially constructed, and because the evaluators might desire to inspect the internal components more closely than a cursory visual exam could prove. The reviewer may want to inspect the robustness of the internal components beyond a visual inspection. However, in this respect, the visibility component of the project – both for inspection by mentors and outside parties, as well as for ease of troubleshooting before project completion – would need to be addressed via the use of a transparent material. Research Related to Project Definition
The project has been split up according to Table 4 given below. The tasks were divided according to estimated difficulty, with each group member taking responsibility for one of the larger tasks (User Interface, Motor Control, and Image processing), and a few of the smaller tasks. Brad will be in charge of user interface, power, firing control, and hardware housing. Fairen will take on the tasks of motor control, wireless communication and PCB design, and Courtney will be responsible for the image processing, rangefinder and Arduino programming. Table : Division of Labor
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