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Revision: August 14, 2007

Note: This document applies to REV A of the board.

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Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.

Overview

The PmodLS1 module is an interface module

for connecting optical sensors to digital inputs

on a Digilent system board. When used with

reflective infrared light detector sensors

(available from Digilent), the PmodLS1 is

ideally suited for use in line-sensing robots. It

is also well-suited for use as a general-purpose

interface for either reflective or transmissive

photo detectors.

The module can be used with Digilent

microcontroller boards or Digilent FPGA

boards.

Functional Description

The PmodLS1 is designed to be used with

sensors containing an infrared LED and an

infrared-sensitive photo-transistor. The

module supports up to four sensors connected

at the S1, S2, S3, and S4 headers. Digilent

has reflective-type sensors available for use

with the PmodLS1. When using Digilent’s

sensors, refer to the print on the board for the

orientation of the wire. If third-party sensors

are used, refer to the connection diagram in

figure 2 or the board schematic available at

of the LED and photo-transistor.

The PmodLS1 uses the VCC pin (pin 6) of the

Pmod connector J1 to power the infrared

LEDs. The module uses analog comparators

to determine when the infrared detectors have

sensed more infrared light than the threshold

limit. The sensitivity of the sensors can be

adjusted by adjusting the onboard

potentiometer.

Figure 1 PmodLS1 Circuit Diagram

Figure 2 Sensor Connection Diagram