Doepfer MKE Universal Midi Keyboard Electronics Kit User Manual
Page 11
User's guide V2
page 11
MKE
Another possibility is to connect a second normal potentiometer to ST6. In this case
R12 has to be removed. The ccw terminal of the additional potentiometer is
connected to GND (available at one pin of ST3/4/5), the wiper terminal is connected
to pin 1 of ST6 and the cw terminal to pin 2 of ST6 (= +5V). This potentiometer can
be used to generate any Midi controller or Midi after touch data.
Even for ST6 the full voltage range 0 ... 5 Volt corresponds to the Midi data range 0
... 127.
Important! Unused inputs of ST3/ST4/ST5 have to be jumpered to GND or +5V.
Senseless MIDI data will be sent if one of the middle pins of ST3/ST4/ST5 is left
open. For this the MKE is delivered with jumpers put on the connectors
ST3/ST4/ST5. Remove these jumpers only if the pin header in question is used to
connect a wheel, potentiometer or after touch sensor as described above. For ST6
this is not necessary because of the pull down resistor R12.
Version 2 of MKE is equipped with two additional pin headers (ST7, ST8) and the
connector ST6 is a three-pin type (please refer to the remarks above):
(9) Jumper for pull up/down resistor ST8
If a jumper is connected to this pin header the corresponding input is connected to
GND (lower position, marked with the GND symbol) or +5V (upper position, marked
with "+") via a 10k resistor. This is required if only a variable resistor or a switch has
to be connected to ST6 (i.e. not a potentiometer with three terminals that works as a
voltage divider). This applies e.g. for after-touch sensors, (foot) switches or foot
controller that have only a two-pin variable resistor available. There are two
possibilities to connect the element in question (switch or after-touch sensor or
variable resistor):
•
The element is connected to the pin header ST6 between the center pin and
GND. In this case a pull-up resistor to +5V is required, i.e. a jumper has to be put
on ST8 in the upper position (+). If the resistance of the element connected to
ST6 decreases even the Midi date value decreases and vice versa.
•
The element is connected to the pin header ST6 between the center pin and +5V.
In this case a pull-down resistor to GND is required, i.e. a jumper has to be put on
ST8 in the lower position (GND symbol). If the resistance of the element
connected to ST6 decreases the Midi date value increases and vice versa.
(10) sound card connector
This pin header is planned to connect a suitable sound card (e.g. a sound cart of the
company Dream). The four pins have these functions (from left to right): +9V, NC,
Midi Out, GND (NC = not connected). The terminal NC can be connected to +5V if
required.