a mini-MIDI vorsetzer?

a mini-MIDI vorsetzer?
(I posted this to MMD, but thought it was worth repeating here) In thinking about the best way to add a MIDI interface to a keyed fairground organ, it seemed to me that one of the easiest, most transferable, and most sympathetic means would be to make a "mini-Vorsetzer" that would clamp on to the keyframe in place of the pressure bar and play the organ by operating the keys just as the book does, rather than by introducing additional plumbing downstream. This would keep the keyframe "exercised" (which I'm told is a good thing), and would be much simpler than other means of MIDI-fying a typical pressure-operated keyframe. I wonder if anyone has made such a thing and how it worked? On a related note, it seems that most MIDI systems I see use relatively archaic systems for data storage and transfer (like floppy discs or proprietary ROMs). How hard would it be to make the organ (or piano) an Ethernet network device with a wireless card so that it could be run off a remote laptop, perhaps displaying an electronic piano roll version of the music, a la Cakewalk? (or at least to use a USB data stick?) As you can tell, I'm not an engineer (but I know there are many lurking here)! :-)

Re: a mini-MIDI vorsetzer?
In thinking about the best way to add a MIDI interface to a keyed fairground organ, it seemed to me that one of the easiest, most transferable, and most sympathetic means would be to make a "mini-Vorsetzer" that would clamp on to the keyframe in place of the pressure bar and play the organ by operating the keys just as the book does, rather than by introducing additional plumbing downstream. A nice idea, Roger. The only thing that springs to mind here is that the notes play when the keys are lifted through the hole in the music, so you would need a lever/reverser linkage so solenoids actually let the keys lift under pressure from their own springs, then when released, heavier springs would be needed to push the keys back down again. You don't want to set it up with the solenoids energized when the notes are "off". All this must be achieved in a key spacing of 3.48mm, no mean feat. Regards, John

I figured that you could use lever arms of various lengths so that the solenoids (do they make linear drive motors that small?) could be arranged in tiers, like the pneumatics on in a player paino. I've found out that such a device was made for Harvey Roehl's 57 key gavioli, here is a picture from DL Bullock's web site www.thepianoworld.com

This looks like they stacked the solenoids vertically (maybe horizontally as well). I hope to track down this organ and have a look at it. Yes, I was imagining the keys to be held down by spring pressure, which would be relieved by firing the solenoid. I think one would want to look for the most compact possible components to make it easy to put the device on and off the keyframe. Cheers, Roger >

Hello everyone, The amount of force involved in moving the keys would mean solenoids of a decent size, so you would have to have several staggered banks to squeeze them into the spacing, hence the large assembly over Harvey's keyframe. Incidentally, the bridge of the keyframe must have been removed to acommodate it, so it's not such a quick change over, but still the best non-invasive solution. A keyless frame would present much less of a headache. Small solenoids with tiny pallets, although you may need a manifold to seperate the holes. This has already been done for player piano tracker bars (remember their hole spacing is even closer together!) in the shape of the 'Poweroll' system made in the USA. One of the problems encountered on the early systems was a build up of heat (due to the close proximity of all those solenoids to each other) melting the very glue that held them together, but I gather that this teething problem has long since been ironed out. There has been plenty written about this product on the MMD, so do a search on there & find out all you'll ever need to know! Rob.

I'm no expert with Midifying, but found some stuff which might be useful on Harald Mueller's website: www.haraldmmueller.de Regards Robert Washington :org:

Great link Robert! More specifically, the following page shows an add-on tracker bar unit to allow MIDI operation on a 20-note roll player (i.e. keyless exhaust pneumatic action): http://www.haraldmmueller.de/midi_en.htm It’s a clever idea having the magnets at the top and bottom of the unit. Thus only to rows are needed, while keeping a magnet spacing of four times the tracker bar spacing.

Here’s an interesting ‘electronic roll’ product from a German manufacture which might be of interest… http://www.ziehorgel.de/aufsetzer_en.htm The item has been discussed in the organ grinders email group, and apparently each one needs to be custom made for the organ, but it’s an interesting concept. The long moving ‘fingers’ look too weak to be adapted to a keyed key frame, and I can imagine difficulty in having something like that fit onto a keyless key frame of a fair organ, bearing in mind in all likelihood there will be a higher air pressure and also closer note spacing. An interesting idea nonetheless.

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