|Nova's Switchbox consists of the vehicle's kill, mission start, and main power switches. The success last year of Triton's switchbox led to the reuse of the design with Nova. The kill switch disables the vehicle's thrusters and is required by the AUVSI competition. The mission start switch provides a physical means of starting and stopping missions. Since the Switchbox is mounted externally, the design of the components had to take into account sealing against water and actuation by divers in water. For most of the components, underwater sealing was accomplished through epoxy potting of the electronics, that is placing the electronics in containers and filling them with epoxy. Underwater actuation was accomplished through the use of magnets and reed switches. The kill switch is shaped like a handle on a circuit breaker to make it easy to pull when a diver is following the vehicle.
On the right is the Switchbox mounted to the vehicle with the kill switch being pulled into the killed position.
Shown above are the actuating components of the kill switch. On the left, an epoxy potted delrin block is shown containing two rare earth magnets. On the right, a delrin block is shown which contains an SPDT reed switch in the top and a steel woodruff key in the bottom. The magnets are on the side of the handle of the kill switch and the reed switch is mounted on the back of a plate such that when the handle is close enough to the plate, the magnets actuate the reed switch and attract to the steel key. An SPDT reed switch is used to simplify wiring the reed switch to the LED board within the kill switch handle such that one output is unkilled and the other is killed.
|The main structure of the kill switch handle consists of two delrin side plates, a clear polycarbonate tube, an aluminum bar, and an LED board mounted to the aluminum bar. The assembly was epoxied together with acylic caps on the ends and clear casting epoxy was poured in with the use of a funnel.|
|The kill switch LED board and handle are shown in the two pictures to the left. The two images are, top down, killed and unkilled. The LED board has eight 1206 package red/green LEDs with corresponding resistors. The board wires directly to the reed switch.|