Doepfer Wheel Electronic
universal Midi Control Electronics especially to connect modulation or pitch wheels, joy sticks, foot controller, breath controller and sustain pedal
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.
Application examples:
- pitch bender
- wheels
- joy sticks
- breath controllers (e.g. Yamaha BC-1/2/3, additional resistor required, please refer to the user's manual)
- foot controllers (continuos)
- foot switches (on/off), momentary or toggle
- rotary potentiometers
- slider/fader potentiometers
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 expression
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
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...+2 V another microcontroller (PIC16LF73) can be delivered at Euro 5.00 additional charge.
- 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 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 spring-loaded wheels or joy sticks as due to mechanical tolerances the exact center position is not always reached.
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.
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
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 data).
Even voltages sources can be used instead of the controlling elements. An example for this application are the Yamaha breath controllers BC-1/2/3. In this case the voltages applied to WE have to be strictly within the range 0...+5V (referenced to WE GND) ! Voltages beyond this range will destroy the WE !
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, 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 30 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.
We do not offer a suitable housing as this would have to be completely different for various combinations of controlling elements.
An external power supply (7-12VDC@min. 100mA) is used. The wall outlet power supply adapter for 230V mains voltage and European type mains plug is included with the WE.
Electronic basic knowledge is required to install the WE electronics and to connect the controlling elements resp. control voltages. If you are not sure if your knowledge is sufficient please consult an expert.
For detailed information the user's manual is available as pdf file.
