Doepfer Wheel Electronic User Manual

DOEPFER MUSIKELEKTRONIK GMBH

WHEEL ELECTRONIC

(Universal Midi Control Electronics for

Modulation Wheels, Foot Controllers , Breath-

Controller, Joy Sticks etc.)

V1.0

© 2007 by Doepfer Musikelektronik

Table of contents

Table of contents......................................................................................................................................2

Electrical safety / EMC compatibility......................................................................................................... 2

Warranty...................................................................................................................................................3

Introduction...............................................................................................................................................4

Connection and Installation...................................................................................................................... 5

Power Supply (1) .................................................................................................................................. 5

Midi Out Socket (2)...............................................................................................................................5

Midi In Socket (3)..................................................................................................................................7

LED Control (4).....................................................................................................................................7

Connectors for the four analog controls (5) .......................................................................................... 7

Connector for the switching control (6).................................................................................................9

Controls and Operation .......................................................................................................................... 10

Function of the jumper area JP1......................................................................................................... 10

Function of the jumper area JP2......................................................................................................... 12

Function of the trimming potentiometer P1.........................................................................................12

Mounting.................................................................................................................................................13

Check list................................................................................................................................................14

Extent of delivery....................................................................................................................................15

Appendix: Connecting the modulation wheel box to Wheel Electronic................................................... 15

Electrical safety / EMC compatibility

WHEEL ELECTRONIC (abbreviated "WE" in the following) is a so-called OEM product (OEM

original equipment manufacturer) that cannot be used independently but has to be combined
with additional electrical or electronical equipment to become a working device (e.g.
potentiometers, switches, power supply, case/housing). The manufacturer of WE does not know
the final assembly of the complete device in which the WE is used as a part of the complete
device. The final responsibility with regard to electrical safety and electromagnetic
compatibility is up to the user who is assembling the complete device.

Electronic basic knowledge is required to install WE and to connect the controls resp.
control voltages. If you are not sure whether your knowledge is sufficient please consult an

expert. We cannot take back modules that became defective because of wrong installation or
wrong connection of the controls or voltages.

Please pay attention to the following items:
The power supply used in combination with the WE has to be a closed type (in Germany a

power supply with VDE approval is required). Normally an AC adapter with plastic case is used.
It is not allowed to use open power supplies whith open mains voltage access (e.g. via mains
lead, pcb tracks, electronic parts).

On the WE preventing measures against electromagnetic radiation are taken (e.g. an RF
filter at the power supply input). But it is impossible to estimate to what extend the components

added by the user affect the EMC properties of the complete assembly. Therefore the
complete device has to be shielded against electromagnetic radiation (incoming and

outgoing). These demands are normally met by a closed metal case that covers the complete
assembly. The metal case should be connected to GND of the WE.

Page 2 Wheel Electronic V1.0 User's Guide

Warranty

• Applying any negative voltage (< 0V) or positive voltage above +5V (> +5V) to one of the

five inputs ST1…ST5 will destroy the circuit !

• If potentiometers and/or switches are connected between GND and +5V of WE as

described in this manual no problems will occur.

• When external control voltages are connected to WE the user has to pay attention that the

voltages applied are strictly within GND and +5V referenced to GND of WE !

• Do not solder directly to any of the pin headers but use cable sets with suitable female

connectors to make the connections between WE and the potentiometers, switches,
voltages or other parts. A cable set that contains all required connectors and cables is
included with WE.

• Carry out all connections in the off-state of WE (i.e. when powered-off only) !

• Do not power on WE (i.e. do not connect the power supply to the corresponding jack

socket) before all five inputs ST1…ST5 are connected. Do not leave analog inputs
unconnected ! Unused inputs have to be connected or jumpered to GND or +5V.

• WE electronics is an electrostatic sensitive device. Avoid any electrostatic charges ! Do not

touch any of the inputs with your fingers !

• Avoid short circuits !

• Ignoring any of these items will cause warranty loss !

• Return of the WE within the 2 weeks return time limit (valid only in Germany) is only

possible if all these items have been met. Return of used cable sets is not possible. We also
cannot take back modules that have been soldered by the user.

User's Guide Wheel Electronic V1.0 Page 3

Introduction

• WE is an universal DIY kit to built your own Midi control box. Up to four analog controls and

one switching control can be connected to WE transmitting five different Midi messages.

• The controls (e.g. modulation wheels) are not included but have to be purchased by the

customer in addition. We have suitable parts available as spare parts.

• Typical examples for analog controls connected to the pin headers ST1…ST4 are

modulation wheels, foot controllers, joy sticks, rotary potentiometers, faders, drawbars,
rotary switches (with resistor chains connected between GND and +5V to generate several
analog voltages), ribbon controllers, pressure sensors, light depending resistors or breath
controllers.

• Typical examples for the switching control connected to the pin header ST5 are momentary

or toggling foot switches or any other switches. But even more unusual parts like photo
diodes or photo transistors can be used.

• 16 so-called presets are available. A preset defines the assignments of Midi messages to

the five control inputs ST1…ST5. The actual preset is selected by a group of jumpers.
Different combinations of Midi control change, pitch bend and (monophonic) after touch
messages are available (pitch bend and after touch are no control change messages). If in
the following the term controllers are used this includes pitch bend and after touch too.

• If none of the presets is suitable for the application other combinations of Midi controllers

can be programmed upon request as a special design. Please contact Doepfer
Musikelektronik GmbH for details like additional charges or delivery time (e.g. via email to
[e-mail] or [e-mail]).

• For each of the four analog inputs a jumper is available to select if the full voltage range

(0...+5V) or an adjustable voltage range (0…+V with V+ = +3...+5V) is used for
measurement. This measure is necessary e.g. for modulation or pitch wheels, foot
controllers or joy sticks that do not cover the complete angle of rotation. If such an element
is connected to GND and +5V the maximal output voltage is much less than +5V (e.g. +3V
only). Even breath controllers (e.g. Yamaha BC-1/2/3) output only about +3.5V maximal
voltage. If an electronics is used that analyses the full voltage range 0...+5V the higher Midi
data values are missing. A high resolution trimming potentiometer is available to adjust the
limited voltage range.

• If an element is assigned to Midi pitch bend a "plateau" is used in the middle of the

voltage/data range (data value 64). This feature is meaningful in combination with spring­loaded wheels or joy sticks as due to mechanical tolerances the exact center position is not
always reached

• Even voltages sources can be used instead of the controls provided that the voltages

applied are strictly within the range 0...+5V (referenced to WE GND)! Voltages beyond this
range will destroy the electronics !

• The four analog controls are connected to four single row pinheaders (three pins each). The

switching control is connected to a pinheader with two pins. Cable sets with suitable female
connectors are available. In this way the controls might be disconnected from the electronics
very easily.

• WE is equipped with Midi In and Midi Out. The incoming Midi messages are merged to the

data generated by WE provided that the Midi data does not exceed a certain amount. In this
way several WE can be linked together to obtain larger controller arrays

• WE is available only as an assembled and tested pc board (about 59 x 56 x 25 mm).

• An external power supply (7-12VDC@min. 100mA) is required for the WE. It is included for

all shipments within Germany (230V version with European mains plug). For shipments
outside Germany please ask your local representative or dealer.

• We do not offer a suitable housing as this would have to be completely different for various

combinations of controls.

Page 4 Wheel Electronic V1.0 User's Guide

Connection and Installation

Please pay attention to the following notes !

Electronic basic knowledge is required to install the WE electronics and to connect the controls.
If you are not sure whether your knowledge is sufficient please consult an expert. We cannot
take back modules that became defective because of wrong installation or wrong connection of
the controls or voltages. We also cannot take back modules or cables which have been
soldered by the user.

Power Supply (1)

WE does not have a built-in power supply. Instead it uses a plug-in type external power supply

(AC adapter). One reason for this feature is electrical safety. Keeping danger voltages (main)
out of the WE increases the electrical safety. Therefore an external power supply of high quality
and safety should be used. If WE is used in Germany the external power supply has to be VDE
approved. Another reason for the external power supply is the fact that mains voltages and plug
types vary considerably from country to country. Using a plug-in external supply WE can be
used any where with a locally purchased power supply, thus keeping the retail price down.

The power supply has to be able to deliver 7-12 VDC unstabilized voltage, as well as a
minimum current of 100mA. WE is switched ON by plugging the AC adapter into a wall outlet
and connecting it to the appropriate jack on the WE board. There is no separate ON/OFF
switch. After power on the preset adressed by the setting of the jumpers is called up.

If the polarity of the power supply is incorrect, WE will not function. However, there is no danger
of damage to the circuitry since it is protected by a diode. The correct polarity is: outside ring =
GND, inside lead = +7...12V. A power supply for 230V mains voltage with European type mains
plug is included with the WE (valid only within Europe, for other countries ask you local Doepfer
representative or dealer).

Midi Out Socket (2)

Connect the Midi Out socket with Midi In of the device to be controlled by WE (e.g. sound
expander, synthesizer, sample player, computer with Midi interface and suitable software,
second daisy-chained WE) via a suitable Midi cable. If you want to control more than one Midi
device you have to use daisy chain Midi Thru / Midi In connection of the devices ore use a
external Midi Thru box.

User's Guide Wheel Electronic V1.0 Page 5