Retrofittable remote control

CD players such as Revox B225, Philips CD100, 101, 104, 204, 303, Marantz CD73, Grundig CD7500 ... can be easily controlled from the listening position thanks to this module.

        remote control Revox B225
Existing handsets for remote can usually control the module, it uses the widely used RC5 code. For example, almost all handset for CD from Philips, Grundig, Marantz ... or even a universal remote control.

All modules intervene in the analog way in the function, it is simulated the operation of the associated button on the front panel. A sonic impairment due to susceptibility as in some digital remote controls is thus excluded.

Revox B225

The plug-in module allows the use of more common CD remote controls and offers an additional functionality by the direct selection of the track numbers via the number buttons, the volume setting of the variable output jacks and the headphone output, or the source selection between CD or digital USB input (only with USB-in module). All special functions can also be controlled with number combinations, as some manual switches have no corresponding keys:
0,1=StdBy, 0,2=Source, 0,3=Loop, 0,7=Volume-, 0,9=Volume+

Installation example: Revox B225

Plug-in module Revox B225, 45 Euro

Function Revox B225

CD100 - CD303 - CD73 ...

All functions of the CD 100, 303, 73 and 7500 remote controllable. The special functions can also be controlled with numerical keys, as some manual switches have no corresponding keys: 1=Cancel, 2=Store/Preset, 3=Select, 4=Repeat
Installation example: CD 100 - CD 303 - CD-73

1st generation, 45 Euro

function Philips CD100

Philips CD104 - CD204 ...

All functions of the CD 104 - CD 204 can be remotely controlled. The special functions can also be controlled with numerical keys, as some manual switches have no corresponding keys: 1=Open/Close, 2=Programm, 4=Repeat
Installation example: CD 104 - CD 204

2nd generation, 45 Euro

function Philips CD104

Philips hand control

The RH8808 handset was chosen because it is superior in function and value to other models. It is intuitive to use well in the dark and does not provide countless keys that are superfluous in the mentioned CD players.

Philips hand control, 58 Euro
remote control Philips

Universal Handset

This handset ensures order on the living room table. He steers beside the CD player still further 3 devices. All you have to do is enter a device code from the enclosed list.

Universal Handset, 20 Euro

Universal remote control

In addition, the handset has a learning function to copy functions of an existing remote control. Macros can also be programmed to perform multiple functions at the touch of a button.

Motorpot remote control

Motor pots such as e.g. The ALPS RK27112MC can be remotely controlled with this module. Nearly all audio handset switches for Philips, Grundig, Marantz (RC5) or even a universal remote control can be used to control the function.

Motorpot remote control, 38 Euro

Motorpot remote module

Installation guide

After connecting the supplied infrared receiver, a 5V supply voltage is required. The motor of the motorpot is connected to PIN 4 and 6. Switching on reduces the volume for a moment.

wiring Motorpot remote module

The left port can control relays for up to 4 sources. The mute button on a remote control switches off all source relays, and when pressed again, re-activates the last known relay.

wiring source relais remote module

A relay for e.g. "Stand By" can be controlled with pin 15. With push buttons to ground / GND can also be controlled manually without remote control.

· Pin 3/4: Motorpot right / left-run
· Pin 13/14: Source selection up / down

With "reverse logic", the switching signal for the relays can be inverted during operation. Depending on the requirements in a pre-amplifier or integrated amplifier or relay cards, the module can provide the necessary signal without any changes to the existing circuit. Pin 16 is to connect to 5 volt for inverting.

General information
Relays are always controlled via a "shield" and can not be connected directly to a microcontroller because of their current consumption. Such a "shield" consists of a transistor or opto-controller, which switches the coil voltage for the relay. Depending on the wiring, this "shield" requires a 5V "signal high" or a 0V (GND) "signal low" from the microcontroller.

The development

In the first attempts to make a Philips CD 204 remotely controllable it quickly became apparent that conventional finished solutions were not suitable. On the one hand, there were no suitable manual switches available for these all-round remote control modules and no changes could be made in the software of the chips used for more suitable manual switches. This lack of flexibility led to quite different problems. Since the CD 204/104 can be used for a number of functions in electrical terms, two switches are actuated, one of which also serves for a different function, these modules could not be used.

remote Philips CD100
Even more important, however, was that a remote control board for these CD player models is made with authentic components from the time epoch and may have no sonic effects. First, it was important to find out why some CD players with original remote control sound worse. Theoretically, two causes came into question for me. The suggestive perception, or the clock frequencies with which such a system works.

As a test object served two CD 304, in one of the original remote control was removed. And indeed, the CD 304 without a remote control sounded a bit more relaxed. In the cause research then Commissioner Zufall was helpful. The door to the factory seat opened a crack, someone put his arm in and pressed the light switch, it was already dawning. There was light and I noticed a slight flicker in the tube display. A defect? Fluctuations in the mains voltage? I put my hand in front of the 304 infrared sensor, the flicker gone. The light of the energy-saving bulbs apparently radiated a wave range, to which the infrared sensor at the 304 reacted. That had to be checked.

The 304 so responsive explained its wiring diagram. The -18 volts for the converter chip, from which directly the analogue signal is obtained, are connected in an original CD 304 with the -36 volt for the control front without special buffering. A flicker in the display, caused by oscillation of the original remote control with a receiver that was still too broadband at the time, directly leads to an influence on a tonally relevant voltage. With an original CD 304, it is advisable to keep the listening area free of disturbing light or simply cover the infrared sensor with a piece of paper.

The decision was made to construct an analogue remote control board, which is electrically decoupled from the circuits of the CD player. As it were simulated the manual keystroke on the control buttons of the CD player, but is also narrowband in the reception. In addition, the important voltage of -18V is independently regulated and buffered on my CD players. For this remote control module to use time-authentic components in the design "DIL", led to some difficulties. There were no approaches to control software available, nor were ready-made devices to burn the software into these old chips. It had to be started at zero and first of all all necessary devices such as this burner and a device for reading the sent codes of various hand switches are constructed.

Fernbedienung Philips CD204

The development of an authentic analogue remote control board with no sonic effects, together with all necessary devices and their own software, took 3 months. In the end, however, it became apparent that the flexibility gained in the software now also made it possible to remotely control other CD players such as the CD 100 with the same remote control module. The fact that almost every handset could be integrated into the software, also allowed a specific adaptation to use only a single remote control for all devices used in the living room.

After 3 years of continuous development, the analogue remote control module was ready for use with all first generation CD player models.