Doepfer wheel electronic with power supply
Wheel electronic (abbreviation: "we" in the
following) is an universal electronics diy midi kit designed to connect
modulation or pitch wheels. but it can be used also for joy
sticks, single or multiple foot controllers (analog or on/off), breath
controllers or even normal potentiometers. In addition a connector for a
sustain foot switch is available.
up to 4 continuously variable "analog" elements and a "digital"
switching element (e.g. a sustain foot switch) can be connected.
breath controllers (e.g. yamaha bc-1/2/3, additional resistor required.
foot controllers (continuos)
foot switches (on/off), momentary or toggle
different elements can be combined simultaneously. here are some examples:
pitch bender, modulation wheel, volume control (rotary or slider potentiometer), breath controller and sustain foot switch
pitch bender, three modulation wheels (e.g. modulation, volume, after touch) and sustain foot switch
pitch bender, two modulation wheels (e.g. modulation and after touch),
one rotary or slider potentiometer (volume) and sustain foot switch
pitch bender, modulation wheel and joy stick
two joy sticks
four foot controllers for volume control of four midi channels
dual or tripe foot controller (on/off or analog) and rotary or slider potentiometer
two modulation wheels or switches to control the rotary speakers of the
organ software b4 (von native instruments), two rotary or slider
potentiometers for volume and
the four "analog" elements are connected to pinheaders with 3 pins. for
the "digital" switching element a pinheader with 2 pins is available.
the pin headers are the white
parts in the above picture. four 3-pin cable sets and one 2-pin cable
set about 30cm each with suitable female connectors are included (please
refer to the pictures of the
applications examples below).
we has some special features compared to other midi control electronics (e.g. pocket electronic):
the upper voltage that is assigned to the midi data value 127 can be
adjusted exactly with a multi-gang trimming potentiometer. 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 control voltage. if an
electronics is used that analyses the full
voltage range 0...+5v the higher midi data values are missing.
the voltage range can be reduced with the trimming potentiometer to
0...+3v. for a still smaller range 0...+2v another microcontroller
lf73) can be delivered at an
for each of the four elements a jumper is used to select if the full
voltage range (0...+5v) or the adjustable voltage range is used for
measurement. this is necessary if
different elements are used simultaneously (e.g. modulation wheels or
foot controller with reduced voltage range and normal rotary or slider
potentiometers with full voltage
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
spring-loaded wheels or joy sticks as due to mechanical tolerances the
exact center position is not always reached.
wheel electronic with modulation wheel set
four jumpers are used to select the midi channel. further four jumpers
are used to select up to 16 different combinations of midi control
change numbers, pitch bend or after
touch - the so-called presets. remark: In the first version of the
firmware not yet all 16 presets are used !). A detailed list of all
available combinations can be found in the
the elements connected to we (e.g. wheels, joy sticks, foot controllers,
normal potentiometers, foot switch) are not included but have to be
added or purchased in addition by the
the midi data range is 0...127 with 7 bit resolution. the sampling rate
is about 50-60 samples/second (according to incoming midi data that
have to be merged to the data
generated by we; the maximum rate is obtained without incoming midi
wheel electronic with four single modulation wheels
we is equipped with midi in and midi out. the incoming midi messages are
merged to the data generated by we- provided that the incoming midi
data range is not too big. in this
way several we can be linked together or combined with other electronics
like ctm64, mke, pocket electronic, and dial electronic.
an led is used to indicate the midi activity.
we is available only as an assembled and tested pc board. the pc board
measures are about 60 mm (length) x 55 mm (width) x 25 mm (height).
several mounting holes with 3 mm
diameter are available for mounting the pc board to a suitable base e.g.
with distance sleeves or spacers and screws.