ELECTRONICS
There are only two pressure vessels on the Stingray that house its main electronics: the computer box and the battery box.
The Computer Box
The computer box consists of a resealable
aluminum housing designed by the iBotics team. The internal cavity of
this enclosure was designed to be the exact dimensions to fit the main
computer, an inertial measurement unit (IMU), a video frame grabber, a
data acquisition card, and a moisture sensor in their most
space-efficient configuration.
The main computer of the Stingray is a Kontron ETX-CD Intel Core 2 Duo based single board computer. The board has a dual core processor running at 1.2GHz, 2GB of DDR2 RAM, 100Mbps Ethernet port, and VGA support. Ubuntu Linux is used as the operating system.
The Labjack U3-HV5 A/D data acquisition card is used to monitor and collect data from a number of the onboard sensors. The data acquisition card communicates this information to the main computer through USB.
As the computer box contains the Stingray's most expensive and essential electrical components, the iBotics team designed and built a custom moisture sensor that indicates if the amount of moisture in the computer box ever reaches a potentially dangerous level. The moisture sensor spans the base of the computer box underneath the main computer and is monitored by the data acquisition card. To further protect against potential component failure due to moisture, a few desiccant packets are also sealed in with the electronics.
The main computer of the Stingray is a Kontron ETX-CD Intel Core 2 Duo based single board computer. The board has a dual core processor running at 1.2GHz, 2GB of DDR2 RAM, 100Mbps Ethernet port, and VGA support. Ubuntu Linux is used as the operating system.
The Labjack U3-HV5 A/D data acquisition card is used to monitor and collect data from a number of the onboard sensors. The data acquisition card communicates this information to the main computer through USB.
As the computer box contains the Stingray's most expensive and essential electrical components, the iBotics team designed and built a custom moisture sensor that indicates if the amount of moisture in the computer box ever reaches a potentially dangerous level. The moisture sensor spans the base of the computer box underneath the main computer and is monitored by the data acquisition card. To further protect against potential component failure due to moisture, a few desiccant packets are also sealed in with the electronics.
The Battery Box
The second pressure vessel is used to house the
power components: two lithium polymer batteries, five electronic speed
controllers, power regulators, the e-stop relay circuit and fuses. The
battery box is constructed from a modified Pelican case.
A 4 Amp-hour 14.8V lithium polymer battery is used to power the main computer and its peripherals including the data acquisition card and sensor array. A second 8 Amp-hour 11.1V lithium polymer battery is used to power the propulsion systems. A Scorpion Commander 45Amp electronic speed controller is used to manage power to each of the motors on the Voith-Schneider propellers. Each of the vertical thrusters is driven by a Castle Sidewinder 25Amp electronic speed controller.
Each of the batteries is connected in series to a 30Amp slow-blow fuse as a redundant hardware safety measure in case the current drawn from any of the electrical components becomes abnormally large, signaling an electrical short or some other potentially dangerous condition, and software is unable to detect and correct the situation.
A 4 Amp-hour 14.8V lithium polymer battery is used to power the main computer and its peripherals including the data acquisition card and sensor array. A second 8 Amp-hour 11.1V lithium polymer battery is used to power the propulsion systems. A Scorpion Commander 45Amp electronic speed controller is used to manage power to each of the motors on the Voith-Schneider propellers. Each of the vertical thrusters is driven by a Castle Sidewinder 25Amp electronic speed controller.
Each of the batteries is connected in series to a 30Amp slow-blow fuse as a redundant hardware safety measure in case the current drawn from any of the electrical components becomes abnormally large, signaling an electrical short or some other potentially dangerous condition, and software is unable to detect and correct the situation.