Wireless midi

DanP

Hello all,

Could anyone give me suggestions on how to get started·learning the subject of "wireless midi". As a project I would like to build a wireless midi transmitter and receiver for my keyboard synthesizer to my sound system. Would anyone have some suggested readings on how to get started with the basics, or even a project that I could look at. Anything would be great, I just want to get started. I appreciate your help.

Dan

Paul Baker

Hmmm, Im a bit confused. You say you want a wireless midi setup running from your keyboard to your sound system. But Im not aware of any soundsystem with a synthesizer built in. All midi is, is·a digital stream of data that specifies note on/off and control parameters, it is not music itself but directions to a synthesizer on what to play. As such an ordinary sound system wouldn't know what to do with the data unless you have a rack mount synth as a front end.

Are you rather saying you want the music output of the synth (speaker out) to be transmitted wirelessly to your sound system? If this is the case, there are existing products on the market to do this. And the bandwidth involved for this is too high for a stamp to deal with.

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Post Edited (Paul Baker) : 12/6/2005 10:07:03 PM GMT

DanP

Paul,

I'm the one that is confused. Sorry. You are right. I am looking for a way to transmit the music output of my synthesizer (speaker out) to my sound system. I want to learn how to build this type of system. I am very interested in it.

But, I am also interested in transmitting midi information from say a wind controller or guitar to a synthesizer. I have seen a few products that do this, but I want to learn how to build this type of system also.

Do you have any suggestions on how I could get started researching these two different applications?

Paul Baker

Ok setting the wireless audio aside for now (it's not that easy and requires extensive external components to do the grunt work if you are using a stamp to control it, since a stamp isn't fast enough to encode audio). The midi transmitter shouldn't be that difficult (well to a novice it would be not that easy either), but here's the rub: a stamp isn't fast enough to do midi receiving. There are examples of doing midi transmitting in a stamp by Jon Williams. Here's a link that rattles off some of the links, check out the nuts and volts articles he did: http://search.parallax.com·enter "midi" into the search form.

He also showed how to make a midi receiver using an SX in this thread: http://forums.parallax.com/showthread.php?p=533525

Now likely you wont want to have to invest in both the SX and the BS, but you should be able to translate the PBASIC code for the midi translator into SX/B (Basic for the SX).

Now for the problems you'll face: I not completely familiar with the midi protocol, but I do not think that midi has a timestamp that is accompanied with commands. If I am correct, this means that you derive the timing off of the time of receipt of a midi command. This means you will have to use an unbuffered wireless system because you will have to receive the data as it comes. If I happen to be wrong about this you could use buffered wireless and use a stamp to do the receiver too, but Im pretty sure I am correct. So when shopping for a wireless module, you should either get a serial stream "as it comes" type, or one that buffers only a single byte and interupts the SX when the full byte is availible.

Perhaps Jon can weigh in on this since he is much more experienced with midi than I am, also other forum member are more experienced in the wireless modules than I am, and hopefully they will chime in on suitible wireless modules.

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Post Edited (Paul Baker) : 12/7/2005 2:37:06 PM GMT

DanP

Thanks Paul