Patent Abstract: Methods and apparatus are provided for insuring that a motor vehicle is being operated by an authorized operator. The apparatus includes an electronic control unit (ECU), an engine immobilizer unit, and a shared encryption key. The ECU generates a challenge by combining the output of a pseudo-random number generator and the output of a somewhat random number generator and cycling the combined number through a linear feedback shift register. The ECU sends the challenge to the immobilizer unit where it is encrypted with the shared key and sent back to the ECU as a response. The ECU uses the same key to encrypt the challenge and compares the encrypted challenge to the response. If the response matches the encrypted challenge, engine operation is enabled.
Front page for patent #4,988,211 issued on 1/29/1991. Patent Abstract: The present invention includes a process and apparatus for determining the temperature of a sample such as urine without contacting the sample itself. A portable device is used to carry the temperature measuring apparatus. The sample of urine is placed in a plastic container on an adjustable support and the temperature is measured by an infrared pyrometer.
Text for patent #483,525 issued on 10/4/1892.
1. The house-door letter-box hereinbefore described, consisting of the frame portion adapted to be permanently secured to the door, having an opening or mouth formed therein increasing in width in a vertical direction from the front, and the box or receptacle b, pivoted to the frame and arranged to be titled back and forth in said opening and having the front b2 of the box arranged to practically conceal the frame-opening.
2. The house-door letter-box substantially as hereinbefore described, the same consisting of the frame portion f, adapted to be permanently secured to the door, having its inner opening wider vertically than the front or outer opening, and the self-closing door box b, pivoted to and arranged to be vibrated or tilted back and forth in the frame, said box being