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Conference napalm::commusic_v1

Title:	* * Computer Music, MIDI, and Related Topics * *
Notice:	Conference has been write-locked. Use new version.
Moderator:	DYPSS1::SCHAFER

Created:	Thu Feb 20 1986
Last Modified:	Mon Aug 29 1994
Last Successful Update:	Fri Jun 06 1997
Number of topics:	2852
Total number of notes:	33157

2753.0. "DIY MIDI?" by ASICS::EDMUNDS (ack no none gal) Tue Oct 22 1991 10:56

    First off: a quick intro. I'm don't have any MIDI equipment today, but
    I'm toying with the idea of getting into MIDI (I do have Tascam 424 +
    guitars, etc). Also, thanks for this conference: I've learnt A LOT
    here. Lastly, in case it matters, I'm in the UK. Now, on with this
    note...
    
    Just browsing through the (newish) Maplin (an electronics shop)
    catalogue this lunchtime I noticed the E510 chip. This is a keyboard
    scanning chip that generates MIDI output: can have up to 96 keys on the
    board. Sends velocity info too.

    Now, gathering dust in my attic somewhere is an electric piano I built
    about ten years ago. The piano part is pretty crappy (noisy,
    unrealistic and about three notes don't work), but the keyboard is a
    61-note full size one. What do the panel think about the idea of trying
    to convert it to a MIDI keyboard?

    I don't even have any MIDI SGU so I wouldn't be able to test it
    initially, but seeing as the chip mentioned cost �25 (~$40), and given
    that I have the keyboard itself, I could end up with a MIDI keyboard
    for, say, �50 (~$85), which has to be pretty cheap.

    So...have I missed anything obvious? Oh, and one more question: the bit
    of blurb in the Maplic catalogue said that the MIDI output baud rate
    was dependant on the clock speed driving the E510. I would have thought
    that MIDI had a standard baud rate?

    Anyway, discussion or whatever is invited. I've posted this in
    SUBURB::MUSICIANS_UK too.

    Keith

T.R	Title	User	Personal Name	Date	Lines
2753.1	do you want to hack or do you want to play?	EZ2GET::STEWART	Balanced on the biggest wave	`Tue Oct 22 1991 11:44`	10
	Keith, unless you want to do this for the sheer thrill of hacking hardware, just go buy some used synth. You can probably pick up a CZ-101 for US$100 - as an example. For the money you get a nice little miniature keyboard (no velocity), an SGU with lots of buttons to push (and available support software), and a MIDI interface. But if you want to MIDI your piano, yes, the baud rate is fixed, so you have to choose the appropriate clock circuitry to achieve that speed.
2753.2		MANTHN::EDD	We are amused...	`Tue Oct 22 1991 11:50`	4
	Although the chip will "scan the keyboard" you'll still need some sensors installed in the keybed for the chip to scan... Edd
2753.3	An ex-Hardware Buff's View	SHIPS::REMMINGTON_J		`Tue Oct 22 1991 13:19`	22
	If you enjoy messing around with soldering irons and DIY PCBs, and can borrow a scope etc, why not? You'll need an idiots guide to the MIDI standard (I'm sure I've seen one in this conference somewhere, or I think I could dredge one up if you're stuck) and of course you'll need to be sure the sensors on your old piano are compatible with what the chip expects. HOWEVER, I suspect (not sure because I don't know the chip) that without some fairly fancy extra logic you will not be able to set up keyboard splits and layers, which, if you want to use it as a master keyboard for more than one SGU (or even a single SGU if it's multitimbral) could be a pretty serious limitation. In any event, you will need to adapt your keyboard to be able to select the MIDI channel to be used, and set up said splits etc if the chip can indeed hack it. So bottom line IMHO is basically to agree with -2; fine if you enjoy the practical side as an end in itself, but if you're really 'just' a musician wanting a cheap keyboard - don't - your time and blood pressure is likely to be worth more than the extra bucks you'd have to fork out to buy one ready-made. Good luck whichever!
2753.4		DECWIN::FISHER	I understand your concerns. Request denied.	`Tue Oct 22 1991 13:22`	6
	BTW, to get velocity, you have to have TWO switches for the ship to scan on each key. One which switches as the key leaves the top position, and the other which switches when the key hits bottom. Timing the difference between the 2 gives velocity. Don't know if your kb has these already. Burns
2753.5		MIZZOU::SHERMAN	ECADSR::Sherman DTN 223-3326	`Tue Oct 22 1991 13:34`	8
	In the end, I think that you won't save money rolling your own versus going out and buying a keyboard, at least not that much when you consider the cost of your time. Eventually, you may want to add velocity, splits/zones/layers, aftertouch, pitch bend, hold pedal, expression pedal and so forth. You can get that on the used market now for pretty cheap. Steve