Technical Report ECE.P54.2004.12
October 1, 2004
INTEGRATION OF THE BLAUPUNKT RC-10 INFRARED
REMOTE CONTROL WITH THE PROJECT54 SYSTEM
By
PRESCOTT B. ATKINSON
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TABLE OF CONTENTS
Table of Contents................................................................................................................ 1
Table of Figures .................................................................................................................. 2
Abstract............................................................................................................................... 3
Introduction......................................................................................................................... 4
Blaupunkt Hardware ........................................................................................................... 5
Microcontroller Software.................................................................................................... 9
Project54 DLL: RemoteCtrl.............................................................................................. 16
Configuration Application: RemoteConfiguration ........................................................... 20
Conclusion ........................................................................................................................ 24
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TABLE OF FIGURES
Figure 1  Arrangement of the RC-10 infrared remote control and transceiver................. 5
Figure 2  The RC-10 remote control unit.......................................................................... 6
Figure 3  The RC-10 infrared transceiver......................................................................... 6
Figure 4  Pulse train output of the infrared transceiver .................................................... 7
Figure 5  A closer inspection of the transceiver output width pattern.............................. 7
Figure 6  The IDB common interface............................................................................... 9
Figure 7  Attaching the RC-10 transceiver to pin 4 of a DB-25 connector .................... 10
Figure 8  Flowchart of the modified microp() function.................................................. 14
Figure 9  Flowchart of RemoteCtrl.dll............................................................................ 17
Figure 10  Warning dialog box for RemoteConfiguration.............................................. 21
Figure 11  The RemoteConfiguration main dialog......................................................... 22
Figure 12  The configuration dialog for the RC-10 up arrow button.............................. 23
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ABSTRACT
The Blaupunkt RC-10 infrared remote control is a proprietary device
manufactured by the Blaupunkt Corporation which is used to control various
functionalities of Blaupunkt consumer car stereo units. The RC-10 model remote control
is designed specifically for use with automobiles, and is molded in a way such that the
remote control is attached to the steering wheel, and is ergonomically-appealing to the
driver of the car. The purpose of this project was to integrate this proprietary device into
the Project54 system as to add system functionality to the nine buttons provided by the
RC-10, mostly for use in police cruisers which may either lack or have unfamiliar cruise
control button systems, or as a less expensive alternative to professionally installed
hardware pushbuttons. The RC-10, having a convenient large pushbutton which was
given the functional behavior of a voice recognition activation button, also has eight other
buttons which have been given custom Project54 system functionality through a system
dynamic link library (DLL), and a standalone configuration application.
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INTRODUCTION
Project54 is a software and hardware system designed to cheaply integrate voice-
operated control, provide for device data acquisition, and centralize the functionality of
after-market police electronics such as radar units, police radios, and police light-bars.
After-market police devices are controlled and monitored through a microcontroller-
based intermediary, which communicates with the Project54 software through the
system s Intelligent Transportation System Data Bus (IDB), via the common IDB
interface.
The implementation of the Blaupunkt RC-10 steering wheel remote control
(Figure 2) into Project54 occurs in three stages: the modification of microcontroller
software which recognizes unique transistor-to-transistor logic (TTL)-level time codes
provided by the RC-10 infrared transceiver (Figure 3) for each of the nine buttons, a
Project54 DLL which takes action on the one-byte Control Area Network (CAN) packets
transmitted from the IDB interface microcontroller, and a Microsoft Foundation Class
(MFC) C++ program which allows a user to assign a multitude of Project54 functions to
eight of the nine buttons. The ninth button, a large blue  SRC button of the RC-10
remote control was given the same functionality as the system s original hardware push-
to-talk (PTT) button, for operation with the driver s thumb.
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BLAUPUNKT HARDWARE
Figure 1  Arrangement of the RC-10 infrared remote control and transceiver
The RC-10 infrared remote control consists of two pieces of hardware: the remote
control unit which is attached to an automobile steering wheel, and the infrared
transceiver which converts the infrared output signal of the remote control into TTL-level
pulses. When a button on the remote control is pressed, a sequence of pulses is
transmitted to the infrared transceiver. Each of the buttons has a pulse train which has
unique widths associated with it. This pulse train is transmitted approximately every 100
milliseconds while a button is held down on the remote control. The remote control itself
is powered by two 1.5 volt 357-type button cell batteries in series.
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Figure 2  The RC-10 remote control unit
The infrared transceiver is powered with a +13.8 volt car battery supply, consists
of a photo-detector circuit, and provides a TTL-level output signal which remains in the
logic  high state of +5 volts when the photo threshold detector is not being stimulated.
The transceiver was designed to be placed on the instrument panel area of an automobile
(Figure 1). A mostly shaded portion of the instrument panel is desirable to avoid
accidental threshold changes.
Figure 3  The RC-10 infrared transceiver
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Figure 4  Pulse train output of the infrared transceiver
Figure 5  A closer inspection of the transceiver output width pattern
An oscilloscope was attached to the data line of the infrared transceiver, the nine
buttons were activated, and pulse widths were recorded for each of the buttons for the
pattern shown in Figures 4 and 5. Pulses t4 and t5 remained the same width for all nine
buttons. Pulses t2 and t3 were found to be approximately equal in duration for each
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button. These pulse durations are recorded in Table 1. On the release of any remote
control button, a terminating pulse train is transmitted to the infrared transceiver which is
different in duration than the nine unique pulse trains transmitted by the press of a button.
Button t1 (ms) t2 (ms) t3 (ms) t4 (ms) t5 (ms)
SRC(HI/LO) 119.4/117.1 8/6.85 8/6.85 0.625 102.8
OK 118.1 7.42 7.37 0.618 102.7
UP 111 3.81 3.76 0.611 102.8
DOWN 112.2 4.4 4.37 0.634 102.8
LEFT 115.6 6.22 6.15 0.64 102.6
RIGHT 114.4 5.62 5.63 0.633 102.5
VOL UP 108.4 2.58 2.55 0.632 102.6
VOL DN 109.6 3.21 3.16 0.643 102.6
MUTE 113.4 5 4.96 0.6 102.8
Table 1 - Sample receiver pulse times for the 9 remote control buttons
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MICROCONTROLLER SOFTWARE
The IDB common interface device (Figure 6) is designed to be of versatile use.
The PIC algorithm to detect remote control button pushes would be designed as an edge-
triggered timing device to compare measured pulse widths with a known set of measured
timing ranges for pulses t2, t3 and t4 shown in Figures 4 and 5.
Figure 6  The IDB common interface
The IDB common interface uses a PIC 18F876 microcontroller as its computing
core. The PIC 18F876 has various I/O ports which can be used to read TTL-level data.
Bit 5 of the PIC 18F876 PORTB was set as an input and used to probe the output signal
of the RC-10 transceiver. In order to easily interface with bit 5 of the PIC 18F876, the
data line of the RC-10 transceiver was connected to pin 4 of the IDB common interface
device s DB-25 port (Figure 7).
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Figure 7  Attaching the RC-10 transceiver to pin 4 of a DB-25 connector
The PIC timer TMR1 was used to collect pulse durations because of its 16-bit
register width and 1:8 timer post-scaling circuitry. The IDB common interface
microcontroller uses a 16MHz clock, whose frequency is divided by a factor of 8 by the
post-scaling circuit of the microcontroller. This allows for pulses of duration 131ms to
be recorded by the timer before a timer register overflow occurrence, or 2µs elapsing per
increment of the 16 bit TMR1 register. Because none of the pulse widths of
consequence exceeded this timer capacity, as pulse t5 was disregarded as irrelevant and
provides sufficient time for CAN packet transmissions, this timer is ideal for recording
the output of the transceiver. Using the 1:8 TMR1 timer post-scaling setting of the
microcontroller, a simple program was written to record the edge-triggered pulse widths
of the output of the transceiver for eventual use in the PIC program. Those timer values
were transmitted through the IDB common interface RS-232 serial port during the 102ms
t5 pulse. A large set of data for each button was recorded with this method in order to
obtain maximum and minimum count values for these pulses.
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It was discovered that eight of the nine buttons would output a constant pulse time
width format while depressed. However, the large blue  SRC button would output
pulses t2 and t3 at a width of approximately 6.85ms for the first several transmissions as
the button was held down. It would then proceed to produce pulse widths for t2 and t3 of
approximately 8ms and continue until the button was released. The aforementioned
terminating pulse train that resulted from the release of all nine buttons was
approximately identical for each button, and was also analyzed for its maximum and
minimum times. Tables 2, 3 and 4 show TMR1 maximum and minimum number
increment data for pulses t2, t3 and t4. The maximum and minimum range in the
eventual detection algorithm was extended past the maximums and minimums recorded
experimentally for each button to compensate for possible flukes.
Pulse T2 MAX increments MIN increments
SRC LO 3425 3361
SRC HI 4031 3954
OK 3728 3663
UP 1913 1846
DOWN 2215 2145
LEFT 3111 3042
RIGHT 2795 2747
VOLUME UP 1292 1227
VOLUME DOWN 1593 1518
MUTE 2508 2430
RELEASE / TERMNIATION 985 927
Table 2  Maximum and minimum TMR1 increment counts for pulse t2. Release/termination pulse
is measured to be approximately constant for all buttons.
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Pulse T3 MAX increments MIN increments
SRC LO 3411 3395
SRC HI 4017 4001
OK 3712 3698
UP 1897 1882
DOWN 2209 2184
LEFT 3094 3080
RIGHT 2795 2761
VOLUME UP 1299 1273
VOLUME DOWN 1600 1574
MUTE 2496 2466
RELEASE / TERMNIATION 987 975
Table 3  Maximum and minimum TMR1 increment counts for pulse t3. Release/termination pulse
is measured to be approximately constant for all buttons.
MAX increments MIN increments
Pulse T4 323 285
Table 4  Maximum and minimum TMR1 increment counts for pulse t4. Pulse t4 is measured to be
approximately constant for all buttons.
After the pulse widths were recorded, they were implemented into an algorithm
written for the microcontroller in the PIC-C programming language. The microp()
function, which uses the IDB network address 0x2e, was modified from strictly hardware
PTT button duties to this more complex multi-case pulse train detection scheme. A
flowchart of the microp() function is shown in Figure 8. It would be trivial to create a
new special purpose IDB address for this algorithm. Table 5 and Table 6 show the pulse
measurement boundaries for t2/t3 and t4 respectively that were eventually implemented
into the microcontroller algorithm.
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Pulse T2 & T3 MAX increments MIN increments
SRC LO 3450 3330
SRC HI 4100 3900
OK 3750 3625
UP 1950 1825
DOWN 2250 2120
LEFT 3150 3030
RIGHT 2845 2710
VOLUME UP 1335 1200
VOLUME DOWN 1640 1500
MUTE 2530 2400
RELEASE / TERMNIATION 1000 900
Table 5  Implemented maximum and minimum TMR1 increment counts for pulses t2 and t3.
MAX increments MIN increments
Pulse T4 350 250
Table 6  Implemented maximum and minimum TMR1 increment counts for pulse t4.
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Figure 8  Flowchart of the modified microp() function.
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Detection codes for all of the remote control buttons barring the  SRC PTT
button are transmitted each time a known pulse train is detected. The unique 1-byte CAN
packets assigned to each button are recorded in Table 7. Since the PTT button works on
the principle of push, hold, and release, a static flag is used to keep track of the position
of these PTT button states. If the PTT  listen code has been transmitted, the flag is set
to indicate such, and subsequent detections of the  SRC button code will not result in
repeated transmissions of the 1-byte 0x67  listen code. If the button is released while
the PTT button is in the  listen state, a  terminate listening code 0x68 is placed on the
IDB when the release pulse train is detected, and the PTT static flag is set to its  not
listening state. Hence, a PTT code is not placed on the IDB network every time the
 SRC pulse train is detected, only on instances of depression and release.
Button 1-byte CAN Packet
SRC Press 0x67
SRC Release 0x68
Up Arrow 0x65
Down Arrow 0x63
Left Arrow 0x64
Right Arrow 0x62
OK Button 0x66
Volume Up Button 0x60
Volume Down Button 0x61
Mute Button 0x59
Table 7  1-byte packet values assigned to button detection states
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PROJECT54 DLL: REMOTECTRL
A Project54 DLL is a program written in C++, whose purpose is to add
functionality from IDB devices and to communicate with or receive data from existing
Project54 applications. Pre-existing software functions for easy acquisition and
manipulation of Microsoft Windows registry data (RegComlib.h), creation of Project54
graphical user interface (GUI) elements (P54Guilib.h), the ability to send messages to
other Project54 applications (P54Iface.h), and IDB data I/O (IdbComlib.h) can be used to
create a Project54 application. A Project54 application called RemoteCtrl.dll was created
to receive and act upon 1-byte CAN packets transmitted by the microcontroller program
on the IDB, listed in Table 7. The Project54 software libraries used for RemoteCtrl were
RegComlib.lib and IdbComlib.lib. RemoteCtrl performs two functions: it continually
probes the IDB for the eight non- SRC RC-10 CAN packets using the IdbComlib
function idbRead(), and scans the Windows 2000 registry for configurable application
messages and the Project54 applications associated with them. The  SRC button
packets are handled as they would be with a hardware PTT button, through the Project54
PushTalk application. The RemoteCtrl application detects if the WhelenMPCO
application is set as the currently used light-bar. If so, RemoteCtrl draws application
messages from the registry with the RegComlib function getRegIntValue(), and uses them
for message passing upon the receipt of function packets from the IDB. If WhelenMPCO
is not the current light-bar, the WhelenSerial light-bar default settings for applications
and application messages are used. The RemoteCtrl program flowchart is shown in
Figure 9.
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Figure 9  Flowchart of RemoteCtrl.dll
Integer values which correspond to Project54 application functionality are stored
in the Windows 2000 registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Catlab\Project54\remotectrl\Parameters, and
are retrieved by RemoteCtrl. These integer values are listed in Table 8. RemoteCtrl has
the ability to send messages to several other Project54 applications, which include:
lightsapp, pscreen, recordsapp, radioapp, radarapp, gpsapp, and mainscreen, which all
have unique Component Object Model (COM) identifiers. These identifiers are retrieved
with the RegComLib function getRegStringValue().
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Integer Value Functionality/Defaults to Application Associated With
0 Disabled None
1 MPCO Custom/Lights & Siren On lightsapp
2 MPCO Custom/Front Strobes On lightsapp
3 MPCO Custom/Rear Strobes On lightsapp
4 MPCO Custom/Strobes On lightsapp
5 MPCO Custom/Wig-Wags On lightsapp
6 MPCO Custom/Take Downs On lightsapp
7 MPCO Custom/Rear Floods On lightsapp
8 MPCO Custom/Left Alley On lightsapp
9 MPCO Custom/Right Alley On lightsapp
10 Siren On lightsapp
16 MPCO Custom/Lights & Siren Off lightsapp
17 MPCO Custom/Front Strobes Off lightsapp
18 MPCO Custom/Rear Strobes Off lightsapp
19 MPCO Custom/Strobes Off lightsapp
20 MPCO Custom/Wig-Wags Off lightsapp
21 MPCO Custom/Take Downs Off lightsapp
22 MPCO Custom/Rear Floods Off lightsapp
23 MPCO Custom/Left Alley Off lightsapp
24 MPCO Custom/Right Alley Off lightsapp
25 Siren Off lightsapp
32 Radar Audio Up radarapp
33 Radar Range Up radarapp
34 Radar Brightness radarapp
35 Front Antenna radarapp
36 Rear Antenna radarapp
37 Squelch On radarapp
38 Squelch Off radarapp
48 Radio Volume Up radioapp
49 Radio Volume Down radioapp
50 Channel Up radioapp
51 Channel Down radioapp
52 Troop Up radioapp
53 Troop Down radioapp
54 Scan On radioapp
55 Scan Off radioapp
64 Show Window mainscreen
65 Show Window pscreen
66 Show Window recordsapp
67 Show Window radioapp
68 Show Window lightsapp
69 Show Window radarapp
70 Show Window gpsapp
71 Lights Off lightsapp
Table 8  Registry settings and their corresponding application functionality
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When RemoteCtrl finds that a particular button of the eight non- SRC buttons
has been pressed, a message of functionality is sent to the application associated with that
button using the P54Iface.h four-argument function Message(), which is condensed down
to a two-message function called sendMessageToApp(), with arguments for destination
application and message content. For example, a message may be sent to the radar
application to force the radar application to activate the radar s rear antenna. The C++
function to elicit this response would appear as such:
sendMessageToApp(radarapp,L REAR ANTENNA );
If WhelenMPCO is the active system light-bar configuration, then application
function messages are drawn from the strings in the Windows 2000 registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Catlab\Project54\WhelenMPCO\Vocabulary
for switches one through three and buttons two through six, and are stored in character
arrays of wide character type. Otherwise, RemoteCtrl reverts to the WhelenSerial light-
bar configuration, and uses the application messages associated with it.
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CONFIGURATION APPLICATION: REMOTECONFIGURATION
A stand-alone MFC C++ Windows 2000 executable called RemoteConfiguration
was written to manipulate the RemoteCtrl registry parameters as to allow an end-user to
configure eight out of the nine remote control buttons to perform various functions with
the Project54 software. RemoteConfiguration uses the registry manipulation functions
provided by the Project54 header file RegComlib.h in order to store and retrieve integer
values for the eight programmable remote control buttons, located in the key
HKEY_LOCAL_MACHINE\SOFTWARE\Catlab\Project54\remotectrl\Parameters of the
Windows 2000 system registry. RemoteConfiguration manipulates the same integer
values that the RemoteCtrl application reads its settings from, shown in Table 8. The
RegComlib functions getRegIntValue() and setRegIntValue() are used to read and write
these integer values from the Windows 2000 registry. RemoteConfiguration will also
automatically detect the light-bar configuration. If the program finds that WhelenMPCO
is the system s current light-bar configuration, it will draw button labels for the
application s radio buttons which correspond to switches one through three and buttons
two through six from the Windows 2000 registry using the RegComlib function
getRegStringValue(). String values for switches one through three and buttons two
through six are stored in the Windows 2000 registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Catlab\Project54\WhelenMPCO\ButtonLabel.
If WhelenMPCO is found to not be the default light-bar installation, then
RemoteConfiguration will revert to configuration of the standard WhelenSerial type
light-bar.
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When the RemoteConfiguration program is executed, a disclaimer dialog box
pops up, as shown in Figure 10. This dialog is included to warn the user that because the
automobile driver may accidentally press buttons on the remote control, that activation of
emergency signals and sirens may not be advisable.
Figure 10  Warning dialog box for RemoteConfiguration.
After pressing the  OK button on the warning dialog box, the warning will
disappear, and the configuration application can be operated to create or disable
functionality for any of the eight configurable buttons on the RC-10 remote control, as
shown in Figure 11. Eight buttons on the next dialog can be pressed, which will allow
the application user to modify the remote control button settings. If there are valid
integer values stored in the
HKEY_LOCAL_MACHINE\SOFTWARE\Catlab\Project54\remotectrl\Parameters
registry key, the RegComlib function getRegIntValue() is used to retrieve them, and they
will be automatically loaded by the program and used as a default until they are modified.
Otherwise, each integer value in this key will be initialized to 0, the  Disabled setting.
Pressing the  OK button will store any changes made to the RemoteCtrl registry
parameters. Pressing the  Cancel button will have no effect on the registry, and will
abandon any changes made on the remote control button settings.
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Figure 11  The RemoteConfiguration main dialog.
When one of the configuration buttons is pressed, a dialog to configure the
specified RC-10 button will pop up and allow the user to choose some functionality or
disable the remote control button. Figure 12 shows the configuration dialog for the up
arrow button on the RC-10 remote control.
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Figure 12  The configuration dialog for the RC-10 up arrow button.
Any of the radio buttons on the configuration dialog may be chosen as a setting
for the remote control button. When the  OK button is pressed, whatever radio button
has been selected will be stored in a list until the  OK button in the main configuration
dialog box is pressed. If the  Cancel button on a button configuration dialog is pressed,
any changes to radio button storage will be discarded, and the value stored in the registry
at the time will be reverted back to the next time the same configuration dialog is
activated.
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CONCLUSION
The Blaupunkt model RC-10 infrared remote control was created specifically to
be attached to the steering wheel of an automobile. It is molded and designed in order to
be ergonomically appealing and easy to use for the automobile operator while in the
process of driving an automobile. The remote control transmits infrared beams to a
transceiver, which translates the infrared pulse transition levels into electrical pulses.
Three pieces of software were written to integrate the RC-10 remote control with
the Project54 system. The IDB common interface was programmed to recognize the
transceiver-side codes associated with the nine buttons of the RC-10 remote control.
Pulses from the transceiver are captured by creating a circuit between pin 4 of the IDB
common interface device and the data line output of the transceiver. When the
microcontroller ascertains which button had been pressed, an identifier is transmitted
across the IDB in the form of a 1-byte data packet. This packet is then recognized by a
Project54 DLL, RemoteCtrl, and depending on what function is assigned to that
particular button, RemoteCtrl sends functional messages to other Project54 applications
to evoke a program response. Finally, the configuration application is used by an end
user to assign functionality to the eight configurable buttons of the RC-10 as to provide
some functionality for the RemoteCtrl DLL to act upon.