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

1

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

2

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

3

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.

4

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.

5

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.

6

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

7

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

8

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

9

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).

10

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.

11

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.

12

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.

13

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.

14

Figure 8 – Flowchart of the modified microp() function.

15

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

16

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.

17

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().

18

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

19

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.

20

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.

21

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.

22

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.

23

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.

24

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.