Dennis P Lehman

20120271580, Oct 25, 2012

Mar 14, 2012

13/420200

James E. Bartling - Chandler AZ, US
Dennis P. Lehman - Garland TX, US

G06F 19/00
G01R 27/26

702 65, 324658

A touch panel or screen has a serpentine transmission line fabricated on a substrate, e.g., printed circuit board, LCD, plasma or LED screen, etc., and has a constant impedance. Touches to the touch panel will cause changes of impedance of the transmission line at the locations of the touches. Time domain reflectometry (TDR) is used for determining the locations of the changes of impedance of the transmission line by accurately measuring the return pulse times at the source of a plurality of pulses, and then converting the return pulse times to X-Y coordinates of the touch panel or screen.

61761389, Jan 23, 2001

Jul 15, 1998

9/115712

Howard S. Barr - Encinitas CA
Dennis Lehman - Santee CA

SABA Instruments, Inc. - Encinitas CA

G01L 700

73756

An electronic pressure sensor is described that includes a hollow stainless steel insert within a plastic outer housing. A piezoelectric pressure sensor is mounted to one end of the insert while the media to be measured flows into the other end. The insert protects the plastic outer housing from the pressure of the media. A microcontroller reads a digital signal from the pressure sensor and converts the signal into a digital output such as RS-232 or RS-485.

20220236816, Jul 28, 2022

Oct 20, 2021

17/506139

- Dallas TX, US
Dennis Patrick Lehman - Garland TX, US
Miroslav Oljaca - Allen TX, US
Maxwell G Robertson - Dallas TX, US
Merril Newman - Schaumburg IL, US

G06F 3/044
G06F 3/041

A human machine interface (HMI) system and method of operating. The system includes capacitive measurement circuitry coupled to one or more capacitive touch elements, and piezoelectric measurement circuit including interface circuitry coupled to one or more piezoelectric touch elements. The capacitive measurement circuitry includes a gain stage configured to amplify a signal corresponding to a capacitance at the one or more capacitor input terminals by a gain level for communication to processing circuitry. Gain control circuitry is configured to increase the gain level of the gain stage of the capacitive measurement circuitry responsive to the piezoelectric measurement circuitry receiving a user input from at least one of the piezoelectric touch elements. Implementations that further include piezoelectric drive circuitry for haptic output and clearing debris from the keypad are also disclosed.