Linx Technologies EVAL-xxx-LR User Manual

LR Series

Basic Evaluation Kit

User's Guide

Warning: Some customers may want Linx radio frequency (“RF”)

Warning: Linx radio frequency ("RF") products may be

!

!

products to control machinery or devices remotely, including machinery

used to control machinery or devices remotely, including machinery
or devices that can cause death, bodily injuries, and/or property

or devices that can cause death, bodily injuries, and/or property
damage if improperly or inadvertently triggered, particularly in industrial

damage if improperly or inadvertently triggered, particularly in industrial
settings or other applications implicating life-safety concerns (“Life and

settings or other applications implicating life-safety concerns. No Linx
Property Safety Situations”).

Technologies product is intended for use in any application without
redundancies where the safety of life or property is at risk.

NO OEM LINX REMOTE CONTROL OR FUNCTION MODULE
SHOULD EVER BE USED IN LIFE AND PROPERTY SAFETY

The customers and users of devices and machinery controlled with
SITUATIONS. No OEM Linx Remote Control or Function Module

RF products must understand and must use all appropriate safety

should be modified for Life and Property Safety Situations. Such
procedures in connection with the devices, including without limitation,

modification cannot provide sufficient safety and will void the product’s
using appropriate safety procedures to prevent inadvertent triggering by

regulatory certification and warranty.
the user of the device and using appropriate security codes to prevent
Customers may use our (non-Function) Modules, Antenna and

triggering of the remote controlled machine or device by users of other
Connectors as part of other systems in Life Safety Situations, but

remote controllers.
only with necessary and industry appropriate redundancies and

in compliance with applicable safety standards, including without

Do not use this or any Linx product to trigger an action directly

limitation, ANSI and NFPA standards. It is solely the responsibility

from the data line or RSSI lines without a protocol or encoder/

of any Linx customer who uses one or more of these products to
decoder to validate the data. Without validation, any signal from
incorporate appropriate redundancies and safety standards for the Life

another unrelated transmitter in the environment received by the
and Property Safety Situation application.

module could inadvertently trigger the action. This module does not
have data validation built in.

Do not use this or any Linx product to trigger an action directly
from the data line or RSSI lines without a protocol or encoder/
All RF products are susceptible to RF interference that can prevent

decoder to validate the data. Without validation, any signal from

another unrelated transmitter in the environment received by the module

communication. RF products without frequency agility or hopping
could inadvertently trigger the action.

implemented are more subject to interference. This module does not
have frequency agility built in.

All RF products are susceptible to RF interference that can prevent
communication. RF products without frequency agility or hopping

Do not use any Linx product over the limits in this data guide.

implemented are more subject to interference. This module does not
Excessive voltage or extended operation at the maximum voltage could

have a frequency hopping protocol built in.
cause product failure. Exceeding the reflow temperature profile could

cause product failure which is not immediately evident.
Do not use any Linx product over the limits in this data guide.

Excessive voltage or extended operation at the maximum voltage could

Do not make any physical or electrical modifications to any Linx

cause product failure. Exceeding the reflow temperature profile could
product. This will void the warranty and regulatory and UL certifications

cause product failure which is not immediately evident.
and may cause product failure which is not immediately evident.

Do not make any physical or electrical modifications to any Linx
product. This will void the warranty and regulatory and UL certifications

and may cause product failure which is not immediately evident.

Table of Contents

1 Introduction
2 Ordering Information
2 LR Transmitter Evaluation Board
3 LR Receiver Evaluation Board
4 Theory of Operation
4 Using the Kit
5 Development Using the Prototyping Area
6 Range Testing
7 Using the Boards as a Design Reference
8 About Antennas
8 In Closing
9 Online Resources
10 LR Transmitter Evaluation Board Schematic
11 LR Receiver Evaluation Board Schematic

LR Series Basic Evaluation Kit

User's Guide

Figure 1: LR Series Basic Evaluation Kit

Introduction

Linx LR Series RF modules offer a simple, efficient, and cost-effective
method of adding wireless communication capabilities to any product. The
Basic Evaluation Kit gives a designer all the tools necessary to correctly
and legally incorporate the LR Series modules into an end product. The
development boards themselves serve several important functions:

• Rapid Module Evaluation: The boards allow the performance of the LR
Series modules to be evaluated quickly in a user’s environment.

• Range Testing: Using the on-board encoders and decoders to generate
a simplex transmission, a pair of evaluation boards can be used to
evaluate the range performance of the modules.

• Design Benchmark: The boards provide a known benchmark against
which the performance of a custom design may be judged.

• Application Development: An onboard prototyping area allows for the
development of custon circuits directly on the evaluation board. All
signal lines are available on a header for easy access.

The kit includes 2 LR Series transmitters*, 2 LR Series receivers*, 2 extra
PCB-mount RP-SMA connectors, 2 evaluation boards, 2 CW Series
antennas, 1 CR2032 battery, 2 AAA batteries and full documentation.

* One part is soldered to each board. One extra is for use on your first prototype boards.

– –

1

Revised 3/18/2015

Ordering Information

Ordering Information

Part Number Description

EVAL-***-LR LR Series Basic Evaluation Kit

*** = 315, 418 (Standard), 433MHz

LR Receiver Evaluation Board

2

5

7

Figure 2: Ordering Information

LR Transmitter Evaluation Board

3

1

4

2

Figure 3: LR Transmitter Evaluation Board

1. Battery – 3VDC (use a CR2032-style battery only)

2. Power Switch

3. Continuous ON Switches

4. Momentary Pushbuttons

5. Prototyping Area

6. Breakout Header

7. Reverse-Polarity SMA Antenna Connector

8. LR Series Transmitter Module

9. MS Series Encoder

5

1

3

4

6

9

7

Figure 4: LR Receiver Evaluation Board

8

1. Batteries – 3VDC (use 2 AAA style batteries only)

8

2. Power Switch

3. Prototyping Area

6

9

4. Breakout Header

5. LR Series Receiver Module

6. MS Series Decoder

7. Reverse-Polarity SMA Antenna connector

8. LED – D1

9. Buzzer – D0

– – – –

2 3

Theory of Operation

Development Using the Prototyping Area

Transmitter Evaluation Board

The transmitter board is powered by an on-board 3V CR2032 lithium
battery. It has eight SPST pushbutton switches, the state of which is
encoded into a data stream using a Linx MS Series encoder. If a switch
is closed, the transmitter is enabled while the encoder captures the
pushbutton states for encoding and transmission. The encoder powers
down the transmitter when the button is released. Buttons S0 (D0) and
S1 (D1) are used to activate the LED and buzzer on the receiver board.
All of the data lines have been wired out to the header to the right of
the prototyping area and can be accessed for use with other switches,
contacts or microcontrollers.

Receiver Evaluation Board

The receiver board is powered by two AAA batteries. The LR Series
receiver exhibits a sensitivity of greater than –112dBm, so under optimum
line-of-sight conditions, the transmitter / receiver link can operate over
distances of up to 3,000 feet (1,000m). The data recovered by the LR
Series receiver is decoded by a MS Series decoder, and the data lines
are updated to match the state of the data lines (or pushbuttons) on the
transmitter board. To demonstrate this, one data line is used to drive an
LED while another is used to activate a buzzer. This board also has a
prototyping area with all of the receiver and decoder lines brought out to a
header.

In addition to their evaluation functions, the boards may also be used for
product development. They feature a prototyping area to facilitate the
addition of application-specific circuitry. This area has a connection to
VCC at the top and ground at the bottom that can be used to power any
circuitry that is added.

Note: The CR2032-style battery on the transmitter board has very low

current capacity with, only about 3mA available for external circuitry. If
added circuitry requires a higher current, the battery must be removed
and the board powered from an external source.

The holes are plated and set at 0.1" on center with a 0.04" diameter,
making it easy to add most industry-standard SIP and DIP packages to the
board.

On the transmitter board, the data lines from the encoder and the PDN line
from the transmitter have been wired out to a row of plated holes on the
right side of the prototyping area. On the receiver board, the data lines from
the decoder plus the RSSI, PDN, and DATA lines from the receiver have
been wired out. This allows for easy access to connect external circuitry to
the modules, the encoder, and the decoder. Data line D0 is connected to
the buzzer and D1 is connected to the LED.

Using the Kit

Using the kit is straightforward. Simply attach the antennas, turn on the
power and press buttons on the transmitter board. When S0 is pressed,
the buzzer sounds; when S1 is pressed, the LED turns on. When any
button (S0–S7) is pressed on the transmitter board, the corresponding
decoder output (D0–D7) is active high (VCC) on the prototyping header.

– – – –

4 5

Range Testing

Several complex mathematical models exist for determining path loss in
many environments. These models vary as the transmitter and receiver are
moved from indoor operation to outdoor operation. Although these models
can provide an estimation of range performance in the field, the most
reliable method is to simply perform range tests using the transmitter and
receiver in the intended operational environment.

Basic range testing can be performed with the ransmitter and receiver
evaluation boards. To prepare the board for range testing, turn it on
by switching the power switch to the ON position. Pressing S0 on the
transmitter activates the buzzer on the receiver board, while S1 activates
the LED. Switches SW0 and SW1 have been provided to jumper the
buttons and continuously transmit. This allows the designer to turn on the
transmitter and walk with the receiver.

As the maximum range of the link in an area is approached, it is not
uncommon for the signal to cut in and out as the transmitter moves. This
is normal and can result from other interfering sources or fluctuating signal
levels due to multipath. Multipath results in cancellation of the transmitted
signal as direct and reflected signals arrive at the receiver at differing times
and phases. The areas in which this occurs are commonly called “nulls”
and simply walking a little further usually restores the signal. If this does not
restore the signal, then the maximum effective range of the link has been
reached.

Since the evaluation boards are intended for use by design engineers,
they are not FCC certified. The transmitter has been set to approximate
legal limits by resistor R9 so that the range test results will approximate the
results from a well-designed, certified product. For applications where Part
15 limits are not applicable or output levels can be legally raised due to
protocol duty cycle, R9 can be changed according to the Output Power vs.
LADJ Resistance graph in the LR Series Transmitter Module Data Guide.

the battery, switch positions, and antenna connection. Next, measure
the receiver’s RSSI voltage with the transmitter turned off to determine
if ambient interference is present. If this fails to resolve the issue, please
contact Linx technical support.

Using the Boards as a Design Reference

The basic evaluation boards included in this kit are very simple, yet they
illustrate some important techniques that should be incorporated into the
board layout. The module’s mounting pads extend slightly past the edge of
the part. This eases hand assembly and allows for better heat conduction
under the part if rework is necessary. A full ground plane fill is placed on the
bottom of the board. This ground plane serves three important purposes:

First, since a quarter-wave antenna is employed, the ground plane is
critical to serve as a counterpoise (please see Application Note AN-00500
“Antennas: Design, Application, and Performance” for details on how a
ground plane affects antenna function).

Second, a ground plane suppresses the transfer of noise between stages
of a product as well as unintentional radiation of noise into free space.

Third, a ground plane allows for the implementation of a microstrip feed
between the module and the antenna. The term microstrip refers to a PCB
trace running over a ground plane that is designed to serve as a 50-ohm
transmission line. See the LR Series data guide or the calculator available
on our website for details on microstrip calculations.

To achieve maximum range, keep objects such as your hand away from
the antenna and ensure that the antenna on the transmitting board has a
clear and unobstructed line-of-sight path to the receiving board. Range
performance is determined by many interdependent factors. If the range
you are able to achieve is significantly less than specified by Linx for the
products you are testing, then there is likely a problem with either the board
or the ambient RF environment in which the board is operating. First, check

– – – –

6 7

About Antennas

The choice of antennas is one of the most critical and often overlooked
design considerations. The range, performance, and legality of an RF link
are critically dependent upon the type of antenna employed. Linx offers
a variety of antenna styles that can be considered for a design. Included
with your kit are HD Series (315MHz) or CW Series (418MHz and 433MHz)
connectorized whip antennas that should be connected prior to using the
kit. Despite the fact that the antenna is not centered on the board’s ground
plane, it exhibits a VSWR of <1.7 and suitably demonstrates the module’s
best practical performance.

Online Resources

www.linxtechnologies.com

If you have questions regarding any Linx product and have Internet access,
make www.linxtechnologies.com your first stop. Day or night, the Linx
website gives you instant access to the latest information regarding the
products and services of Linx. It’s all here, including:

• Manual and Software Updates

• Latest News

In Closing

Here at Linx, “Wireless Made Simple” is more than just our motto, it is our
commitment. A commitment to the highest caliber of product, service,
and support. That is why, should you have questions or encounter any
difficulties using the evaluation kit, you’ll be glad to know many resources
are available to assist you. First, check carefully for the obvious, then
visit our website at www.linxtechnologies.com or call [phone]
between 8AM and 4PM Pacific Time to speak with an application engineer.

Legal Notice: All Linx kits and modules are designed in keeping with

high engineering standards; however, it is the responsibility of the user to
ensure that the products are operated in a legal and appropriate manner.
The purchaser understands that legal operation may require additional
permits, approvals, or certifications prior to use, depending on the
country of operation.

• Data Guides

• Application Notes

• Knowledgebase

• FCC Information

And much more. Be sure to visit often!

www.antennafactor.com

The Antenna Factor division of Linx offers
a diverse array of antenna styles, many of
which are optimized for use with our RF
modules. From innovative embeddable
antennas to low-cost whips, domes to GPS
antennas, Antenna Factor likely has an
antenna for you, or can design one to meet
your requirements.

by

Figure 5: Antenna Factor Anetnnas

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8 9

LR Transmitter Evaluation Board Schematic

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LR Receiver Evaluation Board Schematic

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– – – –

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Figure 7: LR Receiver Evaluation Board Schematic

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Linx Technologies

159 Ort Lane

Merlin, OR, US 97532

Phone: [phone]

Fax: [phone]

www.linxtechnologies.com

Disclaimer

Linx Technologies is continually striving to improve the quality and function of its products. For this reason, we
reserve the right to make changes to our products without notice. The information contained in this Data Guide
is believed to be accurate as of the time of publication. Specifications are based on representative lot samples.
Values may vary from lot-to-lot and are not guaranteed. “Typical” parameters can and do vary over lots and
application. Linx Technologies makes no guarantee, warranty, or representation regarding the suitability of any
product for use in any specific application. It is the customer’s responsibility to verify the suitability of the part for
the intended application. NO LINX PRODUCT IS INTENDED FOR USE IN ANY APPLICATION WHERE THE SAFETY

OF LIFE OR PROPERTY IS AT RISK.

Linx Technologies DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. IN NO EVENT SHALL LINX TECHNOLOGIES BE LIABLE FOR ANY OF CUSTOMER’S INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING IN ANY WAY FROM ANY DEFECTIVE OR NON-CONFORMING PRODUCTS
OR FOR ANY OTHER BREACH OF CONTRACT BY LINX TECHNOLOGIES. The limitations on Linx Technologies’

liability are applicable to any and all claims or theories of recovery asserted by Customer, including, without
limitation, breach of contract, breach of warranty, strict liability, or negligence. Customer assumes all liability
(including, without limitation, liability for injury to person or property, economic loss, or business interruption) for
all claims, including claims from third parties, arising from the use of the Products. The Customer will indemnify,
defend, protect, and hold harmless Linx Technologies and its officers, employees, subsidiaries, affiliates,
distributors, and representatives from and against all claims, damages, actions, suits, proceedings, demands,
assessments, adjustments, costs, and expenses incurred by Linx Technologies as a result of or arising from any
Products sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for
losses arising from the use or failure of the device in any application, other than the repair, replacement, or refund
limited to the original product purchase price. Devices described in this publication may contain proprietary,
patented, or copyrighted techniques, components, or materials. Under no circumstances shall any user be
conveyed any license or right to the use or ownership of such items.

©2015 Linx Technologies. All rights reserved.

The stylized Linx logo, Wireless Made Simple, WiSE, CipherLinx and the stylized CL logo are trademarks of Linx Technologies.