PAiA 9201DK, 9212K projects kits for Sensor to MIDI 'drum'..

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PAiA 9201DK, 9212K projects kits for Sensor to MIDI 'drum'..

Post by PAiA-Scott »

PAiA 9201DK, 9212K projects kits for Sensor to MIDI 'drum' control

The 9201 MIDI Drum Computer ("Brain") is a pcb and parts kit project 'part' of a system for a pad to MIDI controller.

At one time, we had a complete kit for a MIDI Drum Brain, but sales for it didn't justify us keeping all the items on the shelf to produce the complete kit.

We still have main parts of the unit though, the 9201DK which is the processor and converter board for sending MIDI note messages for the 0-5v dc pulses, and, the 9212K ProcAmp pcb and parts project kit which conditions sensor signals to be 0-5v pulses for application to the 9201DK.

MIDI Controllers <>

Drum Sensor Processing Amplifier. <>

Notes about sensors that can be connected as inputs to the 9212
Percussion Sensors <>

Sensors could be built into pads that are rubber or similar on boards or even practice pads.


9201DK notes

The 9201DK can be configured for stand-alone use by connecting DC power and 0-5 volt DC pulses (percussive envelopes) as trigger inputs. The Tips on Using section of the manual beginning on page 14 explains the way either an external 5V power supply can be used for power, or, an optional 7805 voltage regulator and associated
filter capacitor can be used so a DC adapter can be used for power. Also shown is an example of peak-detector circuitry that can be used for converting various transducers to the DC percussive envelopes for input to the board. Pulses from an external source such as the 9212K or constructed peak-detector circuits connect via the DIP socket position J5. An external +5V supply would be input on pins 9/10 (ground) and 11/12 (+5V) at this position too. See the lower right hand section of the Fig. 2 Schematic for the 9201. With the 9212K, this is a simple flat cable with DIP connectors on each end.

When a DC adapter is used for power, a 7805 +5V voltage regulator must be installed at the IC1 position and a 1uF electrolytic capacitor at the C14 position. The voltage rating of the capacitor must exceed the voltage of the DC adapter (ie 16V or more for a 9-15V dc adapter). The DC adapter connects to points G and +. See the lower left hand section of the Fig. 2 Schematic for the 9201. The 9212K board has the 7805 and converts the 9-12v dc from an external dc adapter to the +5v supply for the 9201DK.

A 324 is a quad op-amp that can be used for the peak-detector trigger conditioning circuit:

Two of these can be used to make the circuitry for all eight inputs. The DC power supply would connect to pins 4 (+) and 11 (ground) on this part. Note, unused cv (trigger) inputs at the J5 position should be connected to ground or to ground via a resistor so spurious transmissions of note messages with velocities in the range of 0-2 are suppressed. A 14pinDIP socket can be installed at the J5 position and a 14pinDIP header with solder terminals used to connect/disconnect the input circuitry, or, wires can solder direct.

The IC5 position is for another optional component, the StaticRAM IC for storing 're-map' or reprogramming of the analog input to MIDI Note Number relationship. The part simply plugs into a socket at this designation. Normally, only map eight can be reprogrammed and it reverts to the default C Major scale when power is removed, but if a 6116 type SRAM is installed, all eight maps can be reprogrammed. These will be revert to the default maps if power is removed, but a special SRAM with an internal battery can be installed and the re-maps will be retained on power-down. This is the MK48Z02 type as mentioned in the using section and available
from Mouser (1-800-346-6873). These are available with various access speeds (nanoSecond ratings), but none are too slow for this application--go for the lowest cost.

sl, 06/26/08
Scott Lee