Abstract: A computer system is provided for protecting access to one or more hardware devices with a hardware device password that is invisible to a user, the system comprising a mobile device and the hardware device, the mobile device including: a memory, the memory storing one or more invisible passwords; an application in the memory; a wireless interface for communicating with the hardware device; and a processor coupled to the memory, the application and the wireless interface, the hardware device including: a memory; a wireless interface for communicating with the mobile device; and a processor coupled to the memory and the wireless interface; wherein the processor in the mobile device is configured to receive a hardware device identifier from the processor in the hardware device; wherein the application in the mobile device is configured to select, based upon the hardware device identifier, the invisible password for the hardware device; and the processor in the hardware device is configured to authenticate the a

Abstract: A computer system is provided for protecting access to one or more hardware devices with a hardware device password that is invisible to a user, the system comprising a mobile device and the hardware device, the mobile device including: a memory, the memory storing one or more invisible passwords; an application in the memory; a wireless interface for communicating with the hardware device; and a processor coupled to the memory, the application and the wireless interface, the hardware device including: a memory; a wireless interface for communicating with the mobile device; and a processor coupled to the memory and the wireless interface; wherein the processor in the mobile device is configured to receive a hardware device identifier from the processor in the hardware device; wherein the application in the mobile device is configured to select, based upon the hardware device identifier, the invisible password for the hardware device; and the processor in the hardware device is configured to authenticate the a

Abstract: A pneumatic depth sensor system for remotely reporting on a depth of a body of fluid is provided. The system comprises a regulated source of compressed gas, a first pressure sensor upstream from a normally-closed electronic solenoid valve, a second pressure sensor downstream from the electronic solenoid valve and a bubbler outlet downstream from the second pressure sensor, the bubbler outlet for locating at a bottom of the body of fluid, the depth sensor system under control of a microprocessor, the microprocessor in electronic communication with the first and second pressure sensors and the normally-closed electronic solenoid valve, and configured to instruct the normally-closed electronic solenoid valve to be in a fully open position or a fully closed position and to rapidly change position in response to a pressure reading from the second pressure sensor.