midicck™ KT & CS

For Keyboard.

SUMMARY

midicck™ (MIDI Contorol Chip Kit) for keyboards is the micro-controller which does make a MIDI controller or a MIDI keyboard by yourself. midicck for keyboards consists of KT and CS series. The KT gets a performed signal having the velocity value of the keyboard. The CS receives a signal from KT of more than one, and transfers that message to the external MIDI sound module. midicck is a microchip which uses the micro-controller of the U.S. Microchip Technology Inc.'s pre-programmed PIC.

Composition
The "x" following the KT means the number of keys which can be input, and the "x" following the CS means the number of the KT which can be accommodated. There is a KT12 to get the 1 octave's keyboard (12 tones) performance now. Because 2 contact points are used for a key, KT is able to input the contact points of 24. And there are CS4 and CS8 which are able to input four KTs and eight KTs.
Function
The KT uses the switch of two per a key, and detects the status of the keys was pushed or released and how was the velocity. The KT uses the structure of the key matrix for the input, and the status of the contacts of 24 (case for KT12) is scanned with 10 points of IO's of 6 input and 4 output in a short time. The signal which was got like this is transferred to CS by using the original serial communication. The KT have flexibility because the range of the note number and the sensitivity of the velocity can be changed. The CS4 outputs the received data from the KT to the MIDIOUT terminal while handling other operations such as damper(sastain) pedal operation and program change's up/down operation. Plus, the CS4 has the function of changing the "velocity curve".

midicck™ PL

For Percussion.

SUMMARY

The midicck PL series is the microchip which can make the MIDI percussion instrument easily by adding PIEZO transducer and the simple analog circuit by yourself. At present, there is the PL1 which single sensor can be input, and the PL2 which two sensors can be input. midicck PL is also microchip which uses the micro-controller of the U.S. Microchip Technology Inc.'s pre-programmed PIC. (PLx has download edition,too.)

Algorithm

The delay of the sound isn't specially forgiven in the percussion instrument. So, midicck percussion system do the MIDI change of the performance signal which has the power level (velocity) of the percussion instrument by the following algorithm. The electric charge which occurred in PIEZO element due to the vibration is amplified in the preamplifier section in the voltage which is suitable for handling first, and prepared in the filter section in two of the detection signal and the power signal. Because it is analog processing here, it can finish the management in the time lag which is realistically about close to 0.

The Digital section (PIC) all the time checks the detection signal in the shorter period than 1µs, and prepares for the next action. Then, the moment the detection signal is caught, the transmission of the MIDI signal is started, and the power level (velocity) measurement is started immediately. The command to sound the sound of MIDI transmits the data of three bytes of Note-on/Note-Number/Velocity. That time required is 320µs/byte. In other words, the time of about 1ms should be necessary as the specifications of MIDI to sound 1 sound. On the other hand, as for the A/D convert, it is possible that it gets the velocity value while the first byte is being transmitted because all the action can be completed in about 40µs. Because the velocity value is transmitted by the third byte, the time lag by the A/D convert isn't added to the time lag of MIDI, so the delay of the time by doing the A/D convert is prevented. The A/D convert of PIC has the satisfactory precision to the velocity which 7bit should be necessary because it is 10bit precision.

Structure

PIEZO sounder that the acquisition is the easiest conforms to midicck as a sensor. The system can be built easily with the fundamental devices such as the resistors etc., an op-amp, a comparator, a logical-IC(7404). 5VDC for digital and the positive and negative power supply of about +/-10VDC for analog conform as a power supply. Containing the analog circuit diagram in reference manual.

Function

The midicck PL series outputs the signal of the channel 10 which it does the layout for the percussion of MIDI. midicck can change them with the NoteUp and NoteDown buttons because the sound source of the various percussion instruments generally is assigned to each NoteNumber (interval) in the rhythm part of the MIDI sound modules. And, it is possible that 8 tones(drumset) are changed by channel switching, too. Refer GM1(General MIDI Level1) Percussion keymap.
Default setting
PL1: #38-Acousric Snare
PL2, Input1: #38-Acoustic Snare / Input2: #35-Acoustic Bass Drum
It be able to change the number with NoteUp & NoteDown buttons.