Browse Prior Art Database

Simplified Pulse Drive Sensor System

IP.com Disclosure Number: IPCOM000113603D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Kobayashi, K: AUTHOR [+2]

Abstract

Disclosed is a simplified pulse drive sensor system with the capability to increase the noise margin of the optical sensors which are used especially for the position where is heavily subject to the external light. (like natural light, room light, etc.) This system has a simplified LED drive and PHOTO Transistor signal detection circuits by software control and utilizes synchronized software sensing with LED current control.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 87% of the total text.

Simplified Pulse Drive Sensor System

      Disclosed is a simplified pulse drive sensor system with the
capability to increase the noise margin of the optical sensors which
are used especially for the position where is heavily subject to the
external light.  (like natural light, room light, etc.)  This system
has a simplified LED drive and PHOTO Transistor signal detection
circuits by software control and utilizes synchronized software
sensing with LED current control.

      The software will chop the switching transistor 1 in Fig. 1 as
LED DRIVE SIGNAL 1 shown in Fig. 2.  If there is any object, the
signal from the amplifier 2 will wave like AMP OUT 2 in Fig. 2.  With
cutting off DC noise by the decoupling capacitor 4 in Fig. 1, the
signal with much less effect by the external light can be obtained.

      The software will detect the signal from the comparator 3 in
Fig. 1 and check the history of the signal state at each software
intervention 3 in Fig. 2 initiated by the timer interrupt.  After
checking the signal state, the software will alternate LED drive
signal.  (OFF to ON or ON to OFF) If the signal state continues the
flip-flop state, the software can detect the object existence.

The longer the history considered by the software, the more the
system noise margin can be.

      By applying this system, the user can obtain the sensor system
with the considerable noise margin to the external light and also
this system is easily implemented witho...