Patents Assigned to Nighthawk Systems, Inc.
  • Watchdog circuit for carbon monoxide monitors
    Patent number: 5828822
    Abstract: A microcontroller supervision circuit comprising an electronic control capable of causing a high-impedance on at least one external pin upon occurrence of a reset condition. A supervision circuit is coupled to the at least one external pin for detecting the high-impedance condition. Upon detection of the high-impedance condition, a signal is generated to indicate failure of the microcontroller to execute code. The microcontroller is programmed to remove the high-impedance condition when code is properly executed within the microcontroller.
    Type: Grant
    Filed: April 21, 1995
    Date of Patent: October 27, 1998
    Assignee: Nighthawk Systems, Inc.
    Inventor: Stephen M. Ernst
  • Automatic calibration method for carbon monoxide monitors
    Patent number: 5659125
    Abstract: A method and apparatus to automatically calibrate a carbon monoxide detector placed in an environment having a known concentration of carbon monoxide. The monitor is placed in a calibration mode in which it reads the output signal from the sensor and normalizes the output signal to a convenient scale. The normalized reading is used to compute a calibration coefficient. The calibration coefficient is stored in a non-volatile memory integrated with the carbon monoxide monitor.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: August 19, 1997
    Assignee: Nighthawk Systems, Inc.
    Inventor: Stephen M. Ernst