USA As Represented by Secretary of the Navy

John R Raposa

Daniel P Thivierge

A device for controlling a video camera in underwater high speed photography in a first aspect includes a plurality of spaced break screen or sense coil members, a projectile for launch through the series of break screen or sense coil members, a video camera operated to video at a predetermined timing upon release of the projectile, and a source of illumination to aid in the video photography. A trigger device such as a break screen or sense coil is positioned immediately up-range of the video camera. With a time delay programmed into a Programmable Array Logic (PAL), a control circuitry receives the trigger information and creates a timed signal to control the operation of the video camera. In accordance with another aspect of this invention, the control circuitry includes discrete logic devices programmed such that gating of the video camera is controlled by the control circuitry at the time the projectile passes the lens of the camera.

Control circuitry for high speed video camera operation

A device for sensing projectile velocity in an underwater environment is provided. The device includes a plurality of evenly spaced voltage coil members positioned in the path of a projectile. Each voltage coil member includes a support frame having an opening therein and a magnetic coil mounted on the support frame, and a sensing member connected to each support frame. The sensing member includes means for outputting a signal responsive to passage of the projectile through the voltage coil member, and a logic arrangement for determining a difference between passage of the projectile between adjacent ones of said plurality of voltage coil members throughout the run thereof, thereby determining a velocity of the projectile.

Device for sensing projectile velocity in an underwater environment

A device for sensing projectile velocity in an underwater environment is provided. The device includes a plurality of evenly spaced break screen members positioned in a path of the projectile. Each break screen member includes a support member, a pair of transparent sheets spanning the support member, a continuous resistive trace sandwiched between the transparent sheets, and a sensing member correspondingly connected to each resistive trace. The sensing member includes means for outputting a signal responsive to impact of the projectile against the break screen, and a logic arrangement for determining a difference between impact of at two adjacent break screens throughout the run of break screens, thereby determining a velocity of the projectile.

Underwater high speed projectile speed sensing device

A system for sensing projectile velocity and position having a plurality of support members positioned in a path of said projectile. Each support member has an aperture with a resistive trace supported in the aperture. The resistive trace can be separated by the projectile's passage. A sensing circuit is joined to each resistive trace and provides a signal indicating separation of the resistive trace. This signal is provided to a logic circuit which provides a single signal indicating separation of each said resistive trace. A data acquisition system provides an output indicating said projectile velocity and position with respect to time.

Speed sensing circuit for underwater projectiles

A device for controlling a strobe light in underwater high speed photography in a first aspect includes a plurality of spaced break screen or sense coil members, a projectile for launch through the series of break screen or sense coil members, a camera having a shutter opened at a predetermined timing prior to release of the projectile and closing at a predetermined timing subsequent to release of the projectile, and a strobe light opposed to the camera for illumination at a time when the projectile passes in front of the camera. A trigger device, such as a break screen or sense coil, is positioned immediately up-range of the camera. With a time delay programmed into a Programmable Array Logic (PAL), a control circuit receives the trigger information and creates a timed signal to control the illumination of the strobe light. In accordance with another aspect of this invention, the control circuitry includes discrete logic devices programmed such that illumination is controlled by the control circuitry at the exact moment the projectile passes the lens of the camera.

Underwater strobe light control circuitry

A fault protection circuit for a power switching device. The circuit compes a driver circuit electrically connected to the power switching device, a saturation comparator electrically connected to the collector of the switching device to determine if the switching device is switching an excessive voltage, and two undervoltage comparators to determine if the gate is receiving sufficient voltage. If the gate is oversaturated the saturation comparator enables the gate of a field effect transistor which drains the gate of the switching device, and the saturation comparator also disables the driver circuit. The undervoltage detectors detect insufficient voltage to the driver circuit and disable the driver circuit. Once the driver circuit is disabled the control circuitry can take corrective action.

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Warren, RI, United States of America

John R Raposa