Ramsey Electronics Model No. ICI2
Do you have a ton of old remote controls around, or even a
universal remote? Put those to real use by training this unique
kit to recognize the remotes, and allow you to control 2 line level
audio sources.
•
IR Receiver module with sensitive element can receive your
remote control up to 11 meters away.
•
Control 2 line level audio sources.
•
Standard RCA jacks for easy hookup.
•
Easy to train to recognize almost any remote control!
•
Runs from 7-15V AC or DC. Use our AC125 wall adapter for long
operation.
•
LED indicator and feedback buzzer lets you know when you are
receiving an IR signal.
IR CONTROL
INTERFACE
ICI2 Page 2
RAMSEY TRANSMITTER KITS
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FM-10C, FM25B FM Stereo Transmitters
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TXE433 or 916 Transmitter & Encoder Module
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TV6C Television Transmitter
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RX433 or 916 Data Transmitter
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TX916 Data Transmitter
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RR1 Wired remote repeater
•
RRW1 Wireless remote repeater
RAMSEY RECEIVER KITS
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FR1 FM Broadcast Receiver
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AR1 Aircraft Band Receiver
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SR2 Short-wave Receiver
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TFM3 Tri Field Meter
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ECG1 Heart Monitor
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WEB1 Walking Electronic Bug
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LLS1 Laser Light Show
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BE66 Blinky Eyes
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PH14,15,16 Peak hold Meters, great for VU meters
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LC1 Inductance-Capacitance Meter
RAMSEY AMATEUR RADIO KITS
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HR Series HF All Mode Receivers
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QRP Series HF CW Transmitters
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CW7 CW Keyer
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CPO3 Code Practice Oscillator
•
QRP Power Amplifiers
RAMSEY MINI-KITS
Many other kits are available for hobby, school, Scouts and just plain FUN. New
kits are always under development. Write or call for our free Ramsey catalog.
ICI2 IR CONTROL INTERFACE KIT MANUAL
Ramsey Electronics publication No. ICI2 Revision 1.3
First printing: January 2004 MRW/DAR
COPYRIGHT 2002 by Ramsey Electronics, Inc. 590 Fishers Station Drive, V ic t or, New York
14564. All rights reserved. No portion of this publication may be copied or duplic ated without the
written permission of Ramsey Electronics , I nc. P rinted i n the United Stat es of America.
ICI2 Page 3
ICI2 IR CONTROL
INTERFACE KIT
Ramsey Publication No. ICI2
Price $5.00
TABLE OF CONTENTS
Introduction ...........................................4
Theory of Operation ..............................5
Learn As You Build ...............................7
Parts List ...............................................8
Assembly Steps...................................10
Setup and Testing ...............................13
Programming.......................................14
Parts Placement Diagram...................16
Troubleshooting ..................................17
Schematic Diagram.............................18
Warranty..............................................19
KIT ASSEMBLY
AND INST RUCT ION MANUAL FOR
ICI2 Page 4
ICI2 INTRODUCTION
Welcome to the ICI2 kit (and if you don’t have the time, wired and tested). We
will give you an overview of IR remote controls and how they typically work and
also how this kit works to help you understand what you’re building.
Virtually any modern day consumer audio or video device contains an infrared
remote control unit. Usually our living room contains several of these to control
different appliances. In fact we often have so many of these little gems that it
becomes necessary to obtain an “all in one” remote control that controls all the
functions of your entertainment system. Of course, this leads to having several
remote control units delegated to the junk drawer, and this brought about the
idea for the kit. Let’s put the old remotes to use with an easy to build kit that will
control four separate outputs. By toggling a relay for each, we can live the life of
the future by remotely controlling our fans, lamps, and even the coffee pot!
Let’s dig into these units a little bit. A typical infrared remote contains a few
functional parts in common with each other; we’ll examine them. First, there is
some type of keypad assembly. Nowadays this is typically a large molded sheet
of rubber with the buttons protruding outward. The inside of the button that you
cannot see is typically coated with a carbon “button” that will make contact with
the printed circuit board underneath, complete in the circuit when the button is
depressed (no, it’s not sad, it is just making contact!). This switch closure will
cause an Integrated Circuit on the circuit board to repeat a pre-determined
code at the output. This digital signal typically drives an infrared diode to
conduct on the front of the unit “broadcasting” the infrared signal to the
equipment to be controlled.
Our eyes are sensitive detectors in the visible light range, but the wavelength
of the infrared diode falls outside that detection range. So we can’t see the
diode performing its function. But rest assured, given a fresh battery, it is
dutifully doing it over and over again. These codes are unique so that the
infrared detector on the equipment can determine what function each of the
buttons should be and perform these functions. These controlling codes are
unique to each manufacturer, so our kit needs to “learn” these codes to perform
the functions we require.
ICI2 Page 5
ICI2 THEORY OF OPERATION
The ICI2 may look quite simple, but there is actually quite a lot to it inside the
parts. Many items are inside the IR receiver part (U4) that if built up with discrete components would never fit in this little kit case! Inside this part there is
an IR detector diode, amplifier, AGC circuit, bandpass filter, a peak-hold circuit, an integrator, comparators, and an output amp. Heck, the part is a kit in
itself! Just be glad it is in one nice module all ready to go.
Your IR remote control sends data on a 38kHz carrier, much like an FM or
AM radio does. It does this to increase range, and decrease interference from
other IR sources such as ambient light. It is done in an OOK (on off keying)
fashion, meaning that the IR LED is switched on and off at a rate of 32kHz for
a certain duration for a one, and another certain duration for a zero, with
pauses of no carrier in-between each one and zero. A common remote control
format does some special things to differentiate a one from a zero for digital
sending and receiving of data.
When the IR detector “sees” a 38kHz IR signal, the output of the detector
goes low (it is inverted), when there is no 38kHz signal, the output idles high.
On the output of the IR detector you won’t see the 38kHz, just the data that
the 38kHz represents from your IR remote control. This allows the remote
control to save power since the IR LED is on a minimal amount of time.
Typically a remote control will send data in a format consisting of time slices.
To send a zero, the IR LED will be off
for one time slice, and then toggled at
a rate of 38kHz for the second time
slice. To send a one, the IR remote will
use three time slices. Off for two time
slices, and on for one. This makes
things easy on the receiver side, because we just have to look from the
edge of the first on-to-off transition to
the middle of the second time slice (1
1/2 time slices from the start) to determine the bit that was sent.
SAMPLE
0 Bit
1 Bit
START
ICI2 Page 6
An interesting thing is that most remote controls send a unique first code that
can be identified for each and every button, as well as each and every remote
control. Some remotes will send a full data stream over and over as long as
you hold the button down, up to 48 bits per data stream. Other remotes will
only send this full data stream once for the first depression, and then a very
short repeat code usually of only one bit, to save on batteries.
The ICI2 recognizes the full codes, and discards the short repeat codes
unless you are holding a relay in position. If we didn’t do this, we couldn’t tell
one button from another! You will find that with some remotes, you need to
press the button twice to train the ICI2 to remember a certain button. This
means the remote you are using is using repeat codes. Other remotes just
require you to press and hold the button, so these are the ones that send the
same code over and over.
One other variance is the data rate from the remote. Generally most remotes
send at a rate of 2400 Hz time slices, but others send at only 1200 Hz time
slices. This presents a problem since the sample period will always lie in a
high or low portion of the subsequent data, meaning we will receive nothing
but ones or zeros. There is a speed jumper you can install to allow the ICI2 to
work with these remotes. If an incorrect speed remote control is detected, the
microcontroller emits a special beep to let you know the format is wrong. Then
you can switch the jumper over to the other speed and try again, then you will
get either a recognized beep if you have trained the button, or an unrecognized beep if you have not.
When you train the ICI2, the micro controller looks at the IR data stream and
rejects those codes it sees as useless or unverified. The ICI2 looks at the data
from the remote sensor, makes sure it is not a repeat code, checks that it is
not the wrong speed, and then compares it to a previous send before saving
the new value in the Flash m em or y of the controller. That is why you have to
press the button twice on some remotes; so you can get the same code for
verification before saving.
When the ICI2 is normally receiving, it looks at the data stream, and compares it to what was saved. If there is a match, the corresponding function is
run. If there are repeat codes within the allotted time, the same function is repeated continuously until the IR signal goes away.
The ICI2 stores eight codes, each of which are tied to a specific function
(see the on the top of the board layout). For example if you press a button that
you programmed on select 0, the volume will go up a single step. Press it
again, and it goes up another step. Pres s and hold, an d the volume will go up
at the rate of the repeat code sent from the remote. In some cases it may be
rather fast, so you may have to find remotes that don’t send so fast! We have
yet to find one that has been too fast, but we are sure some exist.
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