The final Buoy-cam system provides sufficient real estate to harvest 3448 W-hr/day via solar panels, and fuel cell. Additionally, the Buoy-Cam design has two components that generate power, photo-voltaic panels and a methanol fuel cell. These components provide sufficient generation to power to the Perfect Horizon (PH), video camera, and transmitter continuously for a period greater than one week, depending on the weather conditions. The fuel cell chosen, utilizes methanol and has a relatively low consumption rate. The addition of the solar panels will reduce the fuel consumption rate of the fuel cell and minimize man hours required for maintenance. Also, salt deposits left behind from the evaporated sea water will limit the solar panel efficiency. Weather conditions are variable depending on where the system is deployed and could potentially limit solar energy harvesting altogether. For these reasons, a hybrid system was needed. The Buoy-Cam is powered by rechargeable battery cells that are charged with solar panels whenever conditions permit. When the battery packs drop to a low level, a reserve fuel cell takes over and charges the batteries to prevent system failure. Figure 3 shows the finalized Buoy-Cam frame design. Figure 4 shows the complete system with solar panels, fuel cell, and batteries.
The chosen material for the frame structure was aluminum because the material is non-corrosive in a marine environment, durable (able to withstand over 907 Kg (2,000 lbs)), and relatively inexpensive. The aluminum speed rail fittings will be used for frame construction because they allowed easy assembly and modification.
Camera & Video Transmitter/Receiver
Waterproof Storage Box
The Buoy-Cam will be in a marine environment for extended periods of time. Seawater is highly corrosive, and salt will build up on mechanical components eventually causing them to jam and fail without proper maintenance. This means it is necessary to seal all mechanical and electrical components to minimize salt build up, corrosion and short circuiting of electrical circuits. We used sealed plastic containers to protect the batteries, electronics, and fuel cell. Holes are drilled into these containers for wires which will be feed through rubber grommets. The grommets will ensure the cable passages remain waterproof.
Buoy Frame
The Buoy must have the capability to support a large payload consisting of a fabricated solar panel, fuel cell along with fuel tank, batteries, Perfect Horizon camera stabilizer, camera, and video transmitter. However, the size of the buoy must be taken into account. A buoy over sized, will pose an obstruction to passing ships and create obstacles in the harbor.
Hollow aluminum speed rails were chosen to construct the buoy’s frame. Aluminum was chosen for its resistance to corrosion and overall durability. The speed rail fittings provided the ability to alter the frame structure with ease. The final buoy frame will be a 1.51m x 3.05m (5ft x10ft). This particular size and shape was determined by the size and shape of the solar panels. When used in conjunction with the fuel cell, the system will have enough power generation capability to ensure continuous operation over prolonged periods of time. Another concern about this design was its asymmetrical design, which may pose a balancing issue.
Jetfloat
Functional Requirements:
The buoy must be able to float the buoy and its payload. It should also be easy to install, and remove.
Justification:
The Buoy-Cam will use 8 Jetfloats. Each jet float provides a buoyancy of 980 N (220lbs) and is 0.5m x 0.5m x 0.4m (20in x 20in x 16in). Combination of the 8 jet floats provided a total of 7840 N (1,760 lbs) of buoyancy, which is more than enough to accommodate the overall payload of the system.
Performance Analysis:
They provide more then enough buoyancy to float the Buoy-Cam system, and attachment points allowing for attachment to the frame.
Functional Requirements:
The Buoy-Cam consumes about 1848 W-hr a day when running. Solar panels will provide a portion of energy to recharging the batteries, but will not be capable to to provide the total power needed to sufficiently run the system. Utilizing the solar panels in conjunction with a fuel cell will yield enough energy to power the system.
Justification:
The solar panels, which are on loan from Energy Technologies Inc., were chosen for their durability, flexibility and ability to withstand a rugged environment for long periods of time with minimal servicing. The dimensions of the solar panel are 1.51m x 3.05m (5ft x 10ft) and each panel is flexible enough to bend up to an 0.47m (18in) radius. A single sheet of solar panel contains three strips of photovoltaic cells. Each photocoltaic stripe is 0.381m x 3m (1.33ft x 9.84ft) and under ideal weather condition, each strip is capable to provide 68W of power, or 340 W-hr/day. Maximum power output is 204W. In general, solar systems generate energy on average for 5 hours a day, so our 204W system will generate 1020 W-hr. This is not enough to power the buoy-cam alone and must in tandem with another power source.
Functional Requirements:
The buoy will be located in a harbor and since a surveillance system is much more useful with real-time information, the feed from the camera must be transmitted without interruption to shore. The buoy will not remain in one orientation at all times, the camera must be capable of adjusting for this and the signal must be emitted radially than directed in a specific direction.
Justification:
The HauteSpot router is used because it has the ability to transmit a a high resolution video signal omni-directionally. These requirements cause the router to consume more power than lower frequency routers such as 900MHz or directional transmitters, but satisfy our requirements. The Remote Reality 360 degree camera system has a field of view that allows the Buoy-Cam to have no blind spots and means that buoy rotation is not an issue.
Batteries
Function Requirements:
The system cannot be run directly from the power source. There may be extended periods in which the buoy will not be receiving solar power, and the generator/ fuel cell will be without fuel so the batteries will need to have a large capacity. The Perfect Horizon operates at 24 V so the batteries need to supply 24 V.
Justification:
The Full River DC115-12 are deep-cycle lead acid batteries with an a capacity of 2760W-hrs (115A-hr) at 12V. Two batteries will need to be put into series to provide the 24V needed. Deep-cycle batteries are suggested for use with solar panels, because deep cycle batteries are designed to repeatedly charge and discharge, store charged energy while charging, and are able to deplete down to 80% capacity. At the rated capacity these batteries will power the Buoy-Cam for 36 hours. Since the batteries will be in a harsh environment with a high risk of corrosion, the batteries must be sealed within a water proof container.
Perfect Horizon Camera Stabilizer
Functional Requirement:
Stabilize the top platform to be horizontal to the horizon. Keep video images steady.
Justification:
The Perfect Horizon camera stabilizer is a product from Motion Picture Marine. System comes with a control box that controls the motors and harmonic drives.