Utah Makers

As some of you might know, I have a Roland E-Drum kit sporting a TD-8 drum brain, which I use in conjunction with a Guitar Hero World Tour kit cannibalized for its MIDI inputs (pics below, mod carried out exactly as seen here). Normally this would be exactly what I need, except that the Roland TD-8 brain cannot manually set a separate MIDI note for open and closed hi-hat sounds, whereas Rock Band has them mapped to yellow and blue respectively most of the time. This has the effect of slowly driving me crazy as I play Rock Band, because I have to hit another cymbal when I know that I should really just have to twitch my left foot.

Not being content with the status quo, I decided I would learn how to control MIDI output using an Arduino, and have it act as a MIDI preprocessor, so that I can control the open and closed MIDI outputs in such a way that the GHWT kit takes an open hi-hat to mean blue and a closed hi-hat to mean yellow. Last night I got the first step of this scenario figured out, which is to get the Arduino to interface with my old TD-3 Drum brain (which has the same hi-hat problems as the TD-8), and then have the Arduino send back corrected MIDI notes depending on open or closed hi-hat, while also sending nothing for closing the hi-hat using only the pedal (as this sound is generally not mapped in Rock Band).

I'm still working on getting a working circuit all drawn up properly isolating the MIDI input and output, so I will not post the temporary circuits I am using until I have a finalized design, but I will show you the LED blinking when I hit a drum head, and the mess of a circuit I made (most of it is an old H-Bridge design). I got the design for the MIDI-In circuit from here. I am currently thinking of purchasing a Boarduino to act as the brain of a (more or less) permanent 'preprocessor box' which will run off of battery power (or possibly the 9V power cord for the TD-8), and output light signals corresponding to the pad color being sent to the GHWT MIDI box.

Also on the table is modding an existing Xbox controller to be controlled by the Arduino instead of using the GHWT MIDI connector, as that connector is lacking in transmission of velocity information and differentiating between cymbal and pad hits (i.e. yellow cymbal (hi-hat) vs yellow pad (high tom)), though I have not done any research into how much more work and cost that would entail.

And so, without further ado, here's some pictures of my current setup, the MIDI circuit (in the bottom left corner of the breadboard, the rest is not doing anything here), and my cannibalized GHWT drum kit MIDI box.

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The forum would not let me upload all the pictures in one post, so here are the others:

Parsing the midi stream seems like overkill for switching one signal.

What about a more simple hardware solution of using a reed switch(s) on the pedal to cut the input over between the yellow and blue 'buttons'? (or perhaps I've misunderstood the circuit)

Bill

This is possible, and I attempted it once, before I switched over to GHWT MIDI as my primary input, however I got alot of unwanted notes being played during the switch. The magnets weren't positioned in such a way that it allowed for both of my reed switches to switch simultaneously. I also tried a mechanical switch, and it had (less severe) similar unwanted hit problems. Both solutions felt 'wrong' to me, since I am used to using a normal hi-hat. These Guys have made a box that does it cleanly, but that costs WAY too much for what it does.

MIDI from the drum brain is a much cleaner signal, in my experience, since the TD-8 (or TD-3, previously) has alot more control over drum sensitivity, threshold and crosstalk canceling. I also prefer using MIDI because my TD-8 is much more sensitive than my previous ION Brain module, so I can play more quietly/quickly, even though I lose velocity information and the ability to hear cymbals in fills (GHWT controller limitation). I am still considering hacking up an xbox controller and figuring out how it works so I can use the arduino MIDI solution in conjunction with this hacked controller as my primary input method, bypassing the GHWT box entirely, but that will be a project for another day.

I am currently working out an improved design that will be programmable for all MIDI note inputs, so you can take any MIDI device, and send notes through my Arduino-based preprocessor and output whichever notes you wish. That gives it a more useful existence than this specific Rock Band problem. It will work for anyone interested in inexpensive MIDI preprocessors. Using the built-in EEPROM on the Arduino, I ought to be able to store up to 250 or so notes with an input note number and output note number. (I need a few of the 512 bytes for saving the channel it is operating on among other configuration things.)

I'll keep everyone posted on how this is going, as MIDI can be used for all kinds of fun things (Stage lighting controls based on when I'm drumming while playing rock band sounds like all kinds of fun. ^_^ )

Dude, I don't know how your doing that but that is awesome.... That is why I am excited to learn more about how to use the Arduino and really get involved with things of the sort.