US 5,440,237 AGranted

Electronic force sensing with sensor normalization

AssigneeInControl Solutions, Inc.

InventorsDaniel R. Brown, Philip D. Biehl

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Abstract

Methods and apparatus are disclosed for normalizing electronic sensor data to correct for variations in individual sensor transfer characteristics which are not known in advance. A general characteristic transfer function for a sensor type of interest is determined empirically. A baseline response reading is acquired from an individual sensor, and that baseline response applied to the general transfer function to determine a specific transfer function for the individual sensor. The specific transfer function is used to calculate normalized data. One application of the invention is in computer cursor control pointing devices such as a joystick. Because the invention compensates for wide variations in sensor characteristics, inexpensive sensors such as force-sensitive resistors may be used in a joystick without sacrificing pointing accuracy and ergonomic efficiency.

Claims13

Dependent claims

A method of acquiring data from a individual electronic sensor of a specific type during external stimulus of the individual sensor to correct in-use for variations in sensitivity among sensors of the specific type, the method comprising:

providing a general characteristic transfer function indicative of the sensors of a specific type:
reading a baseline response of the specific sensor in an absence of external stimulus that is indicative of its transfer characteristics;
while an external stimulus is applied to the sensor, reading an activated response value exhibited by the sensor;
determining a specific transfer function for the individual sensor by applying the baseline response to the general characteristic transfer function;
and
applying the specific transfer function to the activated response value to determine an indication of the magnitude of the applied external stimulus, thereby correcting in-use for variations in sensitivity among sensors of the specific type.

3 more elements

Dependencies are inferred from the claim text.