EVAL-***-HHTX
EVAL-***-HHCP
EVAL-***-HHLR
WIRELESS MADE SIMPLE
®
OEM TRANSMITTER EVALUATION KIT USER’S GUIDE
ORDERING INFORMATION
PART #
DESCRIPTION
EVAL-***-HHCP
Compact Handheld Basic Evaluation Kit
EVAL-***-HHLR
Long-Range Handheld Basic Evaluation Kit
EVAL-***-HHTX
Full-Size Handheld Basic Evaluation Kit
EVAL-***-KEY#
Keyfob Basic Evaluation Kit
*** = 315, 418 (Standard), 433MHz
# = Number of buttons: 1 to 5
INTRODUCTION
Linx OEM RF transmitters offer a simple, efficient, and cost-effective method of
adding remote control and command capabilities to any product. The Basic
Evaluation Kit is intended to give a designer all the tools necessary to correctly
incorporate Linx OEM transmitters and receiver modules into a product. This guide
will show how to take full advantage of the basic evaluation board that is included with
the kit. The evaluation board serves several important functions:
• Rapid Evaluation - It allows the performance of the transmitters and receivers to
be evaluated quickly in a user’s environment.
• Range Testing - Using the OEM transmitter and the included development
board, a simplex transmission is generated that can be used to evaluate the
range performance of the products.
• Design Benchmark - During the design process of your product, the kit provides
a known benchmark against which the performance of your own design may be
judged.
• Prototype Development - An on-board prototyping area is provided, which
allows for additional circuitry to be placed directly on the board so that it can act
as the first prototype of the product. All of the signals are available on a breakout
header for easy connection to external circuitry.
The kit includes 2 OEM transmitters, 2 KH2 Series receivers*, 2 PCB-mount RP-SMA
connectors*, 1 development board, 1 CW Series antenna, 2 AAA batteries, and full
documentation.
*One part is soldered to the board; one extra is for use on your first prototype board.
Revised 1/28/08
OEM TRANSMITTER BUTTON ASSIGNMENTS
THEORY OF OPERATION
OEM TRANSMITTERS
Linx OEM transmitters are a great way to quickly bring a remote control product
to market. They are fully assembled and certified, eliminating the need for
design, tooling, and certification. Linx can also customize the transmitters with
customer specific art, logos, or switch layouts.
The operation of the OEM transmitter is straightforward. When a button(s) is
pressed on the OEM transmitter, the states of D0 to D7 are formatted into secure
packets by an on-board encoder IC. These encoded packets are sent to a Linx
transmitter that, through the antenna, conveys the data into free space.
RECEIVER / DECODER EVALUATION BOARD
The receiver board is powered by two AAA batteries. A Linx KH2 Series receiver
is used for reception of the transmitted signal. This receiver provides exceptional
sensitivity, allowing the transmitter and receiver to operate at distances of up to
1,000 feet (depending on TX model and signal conditions). The data recovered
by the KH2 Series receiver is internally decoded. If the settings of the 10-position
DIP switch on the receiver board match the address setting of the transmitter, the
data lines are updated to match the state of the buttons on the OEM transmitter.
To demonstrate this, one data line on the evaluation board is used to drive a LED
while another is used to activate a buzzer. Transistors are used as drive buffers
since the KH2 receiver cannot directly source enough current for these devices.
D7
D5
D3
D1
D6
D4
D2
D0
D3
D0 D4 D2
D1
CMD-HHCP-***
CMD-HHLR-***
CMD-HHTX-***
Figure 1: OEM Transmitter Button Assignments
CMD-KEY#-***
RECEIVER / DECODER BOARD
USING THE KIT
Attach the antenna to the board, set the address on the transmitter and on the
board, turn on the power to the board, and press a button on the transmitter.
SETTING THE ADDRESS
2
3
4
1
5
6
8
7
The Holtek encoder and decoder each have ten address lines that
must
match
in order for the transmitter and receiver to talk to each other. If they do not match,
then the decoder will ignore any transmission and take no action.
The address lines are tri-state, meaning that V
CC
, ground, and floating are
separate and valid states for the address. The OEM transmitters only make use
of the ground and floating states, so the receiver board is designed to match.
To set the address on the receiver evaluation board, note the A0 - A9 labels on
the board and turn the DIP switches on or off as desired. If a switch is on, the
address line is connected to ground. If it is off, then the address line is floating.
The four OEM transmitters have different ways of setting their address lines. For
your convenience, a brief explanation follows; however, the OEM transmitter
manual or Application Note AN-00300 should be referenced for complete details.
The HHTX has an eight-position DIP switch accessed by opening the case.
Switch number 8 corresponds to A0 and number 1 corresponds to A7. A8 and
A9 are floating on the transmitter and must be left off on the receiver board.
The HHCP and HHLR utilize a ten-position DIP switch that is accessed by a
cover on the back of the remote. The switch numbers match the address lines
with switch number 1 corresponding to A0 and number 10 to A9.
The Keyfob has ten internal cut traces numbered 0 to 9 to match A0 to A9. If the
trace is intact, it is connected to ground; when cut, it is floating.
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Battery - 3VDC (use 2 AAA style batteries only)
Power Switch
Buzzer - D0
LED - D1
Prototyping Area
KH2 Series Receiver Module
Reverse-Polarity SMA Antenna Connector
10-Position Address DIP Switch
Figure 2: OEM Basic Evaluation Kit Receiver / Decoder Board
RANGE TESTING
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
usage environment.
Simple range testing can be performed with the transmitter and receiver
evaluation board. To prepare the board for range testing, simply turn it on by
switching the power switch to the ON position. Pressing D0 on the transmitter will
activate the buzzer on the receiver board, while D1 activates the LED.
As you near the maximum range of the link in your area, it is not uncommon for
the signal to cut in and out as you move. 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 will usually restore the
signal. If this does not restore the signal, then the maximum effective range of
the link has been reached.
To achieve maximum range, keep objects such as your hand away from the
antenna and ensure that the antenna on the transmitter has a clear and
unobstructed line-of-sight path to the receiver board. Range performance is
determined by many interdependent factors. If the range you are able to achieve
is significantly less than what is specified by Linx for the products you are testing,
then there is likely a problem either with the board or the ambient RF
environment in which the board is operating. First, check the battery, switch
positions, address settings, 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
Since the OEM transmitters are a finished product, most of the designer’s work
will be incorporating the receiver into their design product. The basic evaluation
board included in this kit is very simple, yet illustrates some important techniques
that you may wish to incorporate into your own board layout. You will observe
that the receiver’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. Next, observe the use of a full ground plane fill on the lower
side of the board. This ground plane serves three important purposes:
First, since a 1/4-wave antenna is employed, the ground plane is critical to serve
as a counterpoise (you may wish to read Application Note AN-00500 “Antennas:
Design, Application, and Performance” for additional details on how a ground
plane affects antenna function).
Second, a ground plane will suppress 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 to 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 between the module and
the antenna. A microstrip is implemented on this evaluation board. If you are
unfamiliar with microstrip calculations, you may wish to refer to the KH2 Series
Receiver Data Guide or the calculator available on our website.
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 you may wish to consider for your design. Included with your kit is a
Linx connectorized whip antenna that should be connected prior to using the kit.
Despite the fact the antenna is not centered on the board’s ground-plane, it
exhibits an outstanding VSWR of <1.7 and suitably demonstrates the module's
best practical performance.
DEVELOPMENT USING THE PROTOTYPING AREA
In addition to evaluation functions, the boards may also be used for product
development. The receiver board features a prototyping area for the addition of
application-specific circuitry. This area has connections to V
CC
at the top and to
ground at the bottom that can be used to power any circuitry that is added.
NOTE:
If added circuitry requires a higher current than can be provided by the batteries,
the batteries must be removed and the board powered from an external source.
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 541-471-6256 between 9AM 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.
The holes are all plated and are set at 0.100” on center with a 0.040” diameter,
making it easy to add industry-standard SIP and DIP packages to the board. The
data line outputs, RSSI, PDN, and DATA line from the receiver have been wired
out to a header row to the right of the prototyping area. This makes it easy to
connect external circuitry to the module and decoder. Data lines D0 and D1 are
connected to the buzzer and LED, but can be accessed by removing the
resistors next to the D0 and D1 labels.
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ONLINE RESOURCES
®
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SW-DIP-10
GND
S1
www.linxtechnologies.com
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BAT-LINX2032
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Latest News
Data Guides
Application Notes
Knowledgebase
Software Updates
ANT1
CONREVSMA001
2-5
1
GND
RF
GND
RSSI
NC
A9
A8
A7
A6
A5
A4
A3
A2
A1
VCC
S4
EG1218
GND
ANT
A0
10
11
12
13
VCC
GND
14
1
2
3
4
5
6
7
8
9
RXD-XXX-KH2
DATA
GND
VCC
PDN
NC
VT
D0
D1
D2
D3
D4
D5
U1
D6
D7
BUZZER
BZ1
CD4069UB HEX INVERTER
VCC
13
12
14
11
10
R3
2.2K
TS1
Test
Strip
1
10
9
8
7
6
5
4
3
2
1
F`
VCC
E`
F
D`
E
D
Q1
2N2222
R7
220 OHM
U2
Q2
2N2222
GND
C`
A`
B`
C
A
B
R6
2.2K
9
8
R4
10K
R5
10K
1
2
3
4
5
6
7
GND
VCC
100k
Figure 3: OEM Basic Evaluation Kit Receiver / Decoder Board Schematic
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0.01uF
C1
LED1
10k
R1
R2
GND
GND
If you have questions regarding any Linx product and have Internet access,
make www.linxtechnologies.com your first stop. Our website is organized in an
intuitive format to immediately give you the answers you need. 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: manual and software updates,
application notes, a comprehensive 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
Yagis, and even GPS, Antenna Factor
likely has an antenna for you, or can
design one to meet your requirements.
www.connectorcity.com
Through its Connector City division, Linx offers a wide
selection of high-quality RF connectors, including FCC-
compliant types such as RP-SMAs that are an ideal
match for our modules and antennas. Connector City
focuses on high-volume OEM requirements, which
allows standard and custom RF connectors to be offered
at a remarkably low cost.
WIRELESS MADE SIMPLE
®
U.S. CORPORATE HEADQUARTERS
LINX TECHNOLOGIES, INC.
159 ORT LANE
MERLIN, OR 97532
PHONE: (541) 471-6256
FAX: (541) 471-6251
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
Overview 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
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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
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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.
© 2008 by Linx Technologies, Inc. The stylized Linx logo,
Linx, “Wireless Made Simple”, CipherLinx, and the stylized
CL logo are the trademarks of Linx Technologies, Inc.
Printed in U.S.A.
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