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Below is the user manual for MIDI-IR version 1.
MIDI-IR User Manual
Introduction
MIDI-IR is part of the Andromeda Space Rockers series of beat-synced drum-machines and synthesizers. The purpose of MIDI-IR is to sync other Andromeda Space Rocker devices to the MIDI clock from a computer, MPC, sequencer, etc... Andromeda Space Rockers use a wireless infrared (IR) protocol to transmit and receive clock information. MIDI-IR has two IR clock outputs, one on each side. MIDI-IR has some other unique features which are described below.
Chassis
You may notice that MIDI-IR is supplied without a case or chassis. This is because we think it looks cool. It also keeps costs low. In general static electricity is not a huge problem, although you may not want to rub a balloon on your hair and then rub the balloon on MIDI-IR. Try not to bend any of the components on the MIDI-IR board. You may choose to make your own case for MIDI-IR.
MIDI in/thru
MIDI-IR has a MIDI-in port and a MIDI-thru port. It receives MIDI clock information as well as start/stop messages from a computer DAW, MPC, sequencer, etc... Clock information is global, so no channel has to be configured. MIDI-in data is passed out the MIDI-thru port for chaining other equipment (or multiple MIDI-IR boards).
Some computer software may not output MIDI clock by default. There is usually an option in the software to enable this. Consult your software manual.
Status LED
There is a status LED which indicates different conditions based on its color and how it is blinking.
| Color | Blink-rate | Meaning |
|---|---|---|
| Yellow | Constantly on | MIDI-IR is on but not receiving MIDI commands |
| Green | Constantly on | MIDI-IR saw the MIDI start command, but not clock |
| Green | Blinking 1/4 notes | MIDI-IR saw both MIDI start and clock |
| Green | Blinking 1/16 notes | MIDI-IR is in BURST mode |
| Yellow | Blinking 1/4 notes | MIDI-IR is seeing clock, but missed the start command |
| Yellow | Blinking 1/16 notes | MIDI-IR is in BURST mode, but missed the start command |
Note that at very fast tempos, the LED may look like it is constantly on when it is actually blinking.
IR Output
There is one IR clock output on each side of MIDI-IR. Each output has a switch to select between two different beat subdivisions. The right side can select between 16th notes and 8th notes, and the left side can select between 16th notes and 12th notes (i.e. 8th note triplets). If you toggle a switch in the middle of a measure, the change won't take effect until the next measure.
At the bottom of the board is a large green button labeled "BURST". When you press this button, you will temporarily change the rhythm used by the right side IR ouput. The change will take effect on the next measure. There are 12 pre-programmed burst rhythms which are selected from pseudo-randomly. Burst rhythms include 32nd note rolls, swing time, triplet fills, and other beats, simple or exotic. Whether the burst rhythm sounds good or bad depends on whatever devices you are driving with MIDI-IR. So if you don't like it, wait till the next measure and it will go away. If you do like it, press the BURST button again and you will lock in the burst rhythm. Press the BURST button a third time to go back to straight 16ths or straight 8ths. For a pdf file of the different burst rhythms, click here.
Firmware
MIDI-IR uses the Microchip PIC 16F688 microcontroller. If you are a PIC hacker and would like to customize your MIDI-IR software, contact me and I will provide you with the source code. The white 6 pin header can be used for in-circuit programming. It has been tested with the PICKit 2 programmer.
Power
MIDI-IR is operated from a single 9V battery. It only draws 6-7 mA, so the battery should last a long time.
The MIDI input and LEDs will keep working down to fairly low battery levels (~2.5 V). However at some point the MIDI thru will not be able to drive enough voltage to the next MIDI device in the chain. If the MIDI thru stops working even though the LEDs are blinking then it may be time to replace the battery.
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