US 4,694,694 A · Solid state accumulating altimeter

Abstract

An altimeter device employs a solid state pressure sensor having a strain-sensitive element directly in a silicon diaphragm, which is connected at one side to a closed vacuum chamber. The entire device is very compact and may be in the form of a wristwatch. A display indicates altitude or relative altitude above or below a reference point to the user, and electronics associated with the device provide for accumulation of vertical change in one direction, regardless of intervening changes in the opposite direction. In this way, a skier, hiker or biker, for example, may determine total vertical drop or vertical rise encountered in a selected period, without regard to offset from movements in the opposite direction. At the same time, the user may also determine his altitude at any given point, and in a preferred form the altimeter device includes a clock and a time-averaging feature, for calculating and displaying rate of climb or descent, both instantaneous and average over a selected interval. The device may also have a time display, so that it functions as a wristwatch as well as an altimeter, and a synthesized voice output may be included for reporting data to the user's ear when visual observation of the display is not practical.

Claims10

Dependent claims

A solid state altimeter device, comprising:

an integrated circuit solid state pressure sensor including a deformable silicon diaphragm with a semiconductor strain gauge in the diaphragm;
a vacuum chamber operatively attached to the diaphragm such that the vacuum of the vacuum chamber is applied to one side of the diaphragm, with the opposite side of the diaphragm exposed to atmospheric pressure;
electrical means connected to the semiconductor strain gauge for conducting an analog signal from the strain gauge representing pressure difference between atmospheric and the vacuum chamber;
a housing containing the pressure sensor and the vacuum chamber;
microprocessor means in the housing for receiving the signal from the electrical means and for converting the signal into an altitude value;
display means mounted in the housing and connected to the microprocessor means for displaying values as controlled by the microprocessor means, to a user;
calibration means connected to the microprocessor means for enabling the user to manually calibrate the altimeter device to a reference value;
and
accumulator means included in the microprocessor means for accumulating altitude change in one direction, disregarding altitude changes in the opposite direction, for a selected interval, and including an accumulation display associated with the display means for displaying said altitude change in one direction.

6 more elements

Dependencies are inferred from the claim text.

Solid state accumulating altimeter

Life of this patent

Solid state accumulating altimeter

Life of this patent

Abstract

Claims10