jimhenry

Your organ layout is going to be much more like a theatre organ than a classical organ even though it will have a classical sound because of the pipes you use. I mention that because as you study how your organ might be arranged, you should know that the information about theatre organs will be more useful than that about classical organs. I realize that you are probably saying 100 outputs because it is a round number but you might as well get used to using the real numbers that will be involved. A basic rank of pipes is 61 pipes because there are 61 notes on an organ keyboard, 5 octaves + 1, and this is normally an 8' pitch. A rank that is extended to fully cover two pitches 16' + 8' or 8' plus 4' has 12 more pipes for a total of 73. For 3 pitches, generally 16 + 8 + 4 or 8+ 4 + 2, you need 85 pipes. For four pitches, almost always 16' + 8' + 4' + 2', you'll have 97 pipes. Now way off topic with regard to Midibox, do you have your pipes or are they yet to be acquired? Assuming you need to acquire your pipes, I am going to assume you'll be using used pipes because your costs will be astronomical if you use new pipes. I think you may have some problems finding ranks of classically voiced pipes that are extended to 97 pipes and maybe even 85 or 73. Even in theatre organ ranks, not many ranks are available with 97 pipes in a rank. The pipes at the top end of a 97 pipe rank are tiny and they all tend to sound the same, at least to humans. The bottom 12 pipes of a 16' rank are huge, heavy, hard to locate, and expensive. You'll need at least 1 octave of 16' pipes to provide a bottom to the pedals, preferably a stopped rank (half length) so the low C will be under 10' when mounted on a chest at floor level. You can miter the pipe or mount it horizontally if you don't have 10 to 11 feet of height. By now I think you will have figured out that I don't think 4 ranks of 97 pipes is needed or even very practical. You can get 16' pitches on the manuals by making 16' tenor C stops from your 8' ranks; these play at 16' pitch but the lowest octave is not present. Pitches higher than 2' are always missing notes at the top end of the keyboard. You can do the same to get 2', 2 2/3', and 3 1/5' pitches from a rank that only has a 4' top end. I'd suggest you use jOrgan to mock up your organ virtually and experiment with ranks and stops to figure out how your ideas are going to work out when it comes to actual performance. Things that look good on paper often turn out quite differently in reality.

Phyto, I didn't realize that your project used real pipes. That is likely to make my answers wrong. Tell us something about the pipes part of your project. What will be the flow of control from the console to the pipes? My experience with pipes is almost all Wurlitzer theatre organs that still use their original electro-pneumatic relays. My thinking will tend to be colored by that background. If you have something quite different, say a classical organ with direct electric valves under the pipes, I'll need to adjust my thoughts and comments accordingly.

By replay do you mean recording a live performance and playing it back? If so, for a virtual organ that would be done on the computer side. The Miditzer provides a MIDI recorder/player built-in. I think the other virtual organs are now catching up on that feature. If not, you can use general purpose MIDI sequencers for that purpose but it is less convenient. I don't understand what you mean by "partition editing." By wifi console I assume you mean a wireless MIDI connection rather than MIDI cables connecting the console to the computer. I don't know of a Midibox project that provides a wireless connection. I know such devices are available and you could use one to replace the MIDI cables to the Midibox. Here's one example of a wireless MIDI device: Wireless MIDIjet Pro from Classic Organ Works

Yes, your understanding of the pistons is correct. I'd suggest downloading the Miditzer and "playing" with it using the screen and mouse to get familiar with things. It is a true virtual organ in that everything is functional without the need for any real hardware. Of course, you need a real keyboard to really play live music but you can explore the function without it. This might serve as a primer with respect to theatre organs: Learning about the Theatre Pipe Organ (TPO) and How the MIDITZER simulates a TPO Section IV of the "Hauptwerk Installation and User Guide" has a primer for classical organs. I don't know if that is available for download separately from the download of the program, which is huge.

The MIDI only has to transmit what changes. The MidiBox scans the whole organ at 1,000 times per second, sees the change, and then sends the MIDI Message that describes that change. If you are using the console to control a virtual organ then it is the virtual organ that does all the multiplication of the notes for the stops and couplers that are on. Even then it is only the changes that generate data so for your example that is 10 notes x 30 stops x 3 bytes = 900 bytes/sec and it normally does not have to be sent via MIDI although it could be. The potential problem is the swell pedal. You have to design things so that the pedal doesn't "jitter" and send two alternating values as fast as the hardware can manage. When there is a problem of MIDI data saturation it is often traced to the swell pedal.

You'll probably want to add a second Core pretty quickly to handle the pedals. I'd wait till then to tackle the stops. You probably don't have pistons on your keyboards. Pistons are more useful than stops for serious playing. I'd add pistons before I did the stops. If you are going to use the Miditzer, adding 11 pistons per manual works well. The 11th pistons are located well to the right and are used for Cancel and perhaps Memory Level. You could wire up 3 pistons on each manual until you get the second Core. Once you have pistons, then you'll probably want indicating stops. You might do that by adding an LED over each stop tab and mechanically reworking the tabs to be momentary on. That will allow you to set a registration with a piston, see the settings in the LEDs, and then add and subtract stops by momentarily touching a stop tab.

PIC will work and there is much information about using it in projects of the type you want to do. You will need multiple Cores that can be linked together with MIDI cables. I assume STM 32 will work too but I have no experience with it. I would suggest doing a smaller project first to get familiar with the technology. MIDIfying an old electronic organ would be a good introduction.

I'd suggest you read this topic in the Miditzer Forum: Building A 4 Manual Console You'll need to register but it's free. That is a very long account of someone building a console. It will give you a better idea of what you are attempting. Maybe it will encourage you. Maybe it will discourage you. It will certainly enlighten you.

An 8x8 scan matrix is possible but I strongly encourage you to just use the extra hardware and do your organ with MIDIIO128. It is much easier and there are many successful examples of that having been done before. The scan matrix is nowhere near as mature and you are likely to spend a lot of time sorting out the Midibox side of things. With MIDIIO128 its full steam ahead on just getting your project done.

I think what you are describing for the push button is a tactile switch. It won't give you the feel of a Wurlitzer second touch but I think it could be better. It's hard to describe the Wurlitzer second touch feel. I guess I'd say it is a short, barely 1/8", and heavy additional travel of the key. The critical factor is that the minimum force necessary to hold the key at the bottom of first touch is significantly less than the minimum force needed to start the movement of the key into second touch. There is a step in the force curve.

I think you still want MIDIIO128 because it is oriented to projects with just DINs and DOUTs. You can use less than the maximum of 4 DINs and 4 DOUTs supported. I couldn't tell you if the whatever64 project is equivalent to MIDIIO128 for 2 DINs as I have only ever used MIDIIO128. I do know that the xxx64 project is primarily used for control surface projects because they use the AIN and AOUT boards as well as DIN and DOUT. Everyone I know who is MIDIfying an organ console uses MIDIIO128.

There is a guide to making the cable for an LCD in the Wiki if you want to take a look: Wiki LCD info

Good to know! They were included when I last ordered a core kit. I guess too many people preferred the chassis mount sockets rather than the PCB mount sockets that used to be included. I suppose it makes sense to make those a la carte so that people can order what they want. Are there enough header pins included to install the two 3 pin headers to connect chassis mount MIDI sockets if you are going that route?

I guess you missed "How to assemble a SmashTV Core module kit" in the Wiki: http://www.midibox.org/dokuwiki/doku.php?id=basics

You are correct about the needed hardware. If you can retain the switches that were used with the electric organ you will make your project much easier.

There is no existing project (firmware code) that I know of to do what you want. If you have the ability to program, it probably wouldn't be too horribly difficult to program the Midibox to serve as a combination action.

While you can build a MIDI Merge using the MidiBox, it is more cost effective to buy a MIDI to USB interface with the required number of inputs if all you need is the merge. BTW, 3 keyboards plus pedal is 4 MIDI In. If you can get by with 4 Inputs rather than 5, you will save quite a bit of money. If you need 5, then you probably should buy 4 and use your existing 1x1 USB for the 5th input.

You are going to have to go to a lower level than MIOS control of the DIN and DOUT to achieve sub-millisecond scanning of a matrix. You either need to get comfortable with what QBAS has done or find TK's earlier sm_8x8 code that QBAS used as a basis for his project. As for using the QBAS code, can you not just ignore the boards you aren't using?

If you are going to plunge into assembly language programming, cut your teeth on something other than the heart of the scan matrix code. I am not a great assembly programmer but I do have more than a passing acquaintance with it. The scan matrix inner loops are not easy to understand even if you are reasonably comfortable with assembly code. When you are ready to tackle the scan matrix, start with TK's example rather than QBAS's extension.

It may not be possible to mix sm and normal pins. I'm not saying it is not possible, just that from what I understand of how sm works I would not be surprised if sm prevented any other use of the pins. You should be able to add debouncing so that once there is a change of state, further changes are ignored for some time. It might even be there already. However, if you speak only C, debouncing may be difficult to deal with. For whatever reason, it doesn't seem like very many people are involved with sm. You are probably going to be pretty much on your own as far as any tweaks are concerned.

850 kOhms sounds like it could be a problem. Connect +5V through a resistor to one column, try 10K to start, and ground one row. Connect a voltmeter between the column connection and ground. You should have +5V with no key pressed. Then press the key at the connected column and row. You want to see the voltage go down, ideally somewhere under 1V. If you really do have 850K resistance between the column and the line, then it won't go down that far. Try larger resistances between +5V and the column and see if you can find something within reason that will give you +5V when not pressed and <1V when pressed. Search the net for information about resistor voltage dividers or resistor networks if you need help understanding what is going on here and how to calculate what sorts of resistor values are needed. While you can make this work even with a large resistance between the column connection and ground, at some point the high resistances will start to make the arrangement "delicate" such that it doesn't work reliably. Where that might be is a bit beyond my off the top of the head knowledge. It may be that the conducting surface on the rubber has worn away or glazed over due to dirt. That may be why it is unreliable now and was sent to the dump. You could try cleaning the contact surfaces with alcohol on a cotton swab and see if that helps. At some point, it will get more expensive to salvage this keyboard than to buy a new one. Figure out what the keyboard would cost to replace with new and keep an eye on your expenses so you don't go "upside down" on the keyboard value.

Actually, not at all exotic. This is exactly how the keys have to be wired for a scan matrix. It takes a little bit of study to get your head around how scan matrix inputs work. The basic idea is that you have one side of the matrix, the columns, as inputs to a DIN. The other side, the lines, are connected to OUTPUTS from a DOUT. The outputs are connected to ground one at a time to read, in your case, the 6 notes for the line that is grounded. That is why you see the lines and columns being connected as keys are pressed. There are diodes in the matrix for reasons I won't go into. You need to verify that they allow the flow of current from a plus voltage on the columns to ground on the lines. If not, then you have to columns to the DOUT and the lines to the DIN.

If you are willing to strip out all the existing electronics and reduce the console to a collection of electrical switches, then yes, MIDIfication is as simple as wiring the switches to the contacts points of a MIDI converter, like a Midibox with 4 DIN boards and running the MIDIIO128 project to provide 128 points of input.

I don't know if MIOS has a facility for a pulse output but I'd be uneasy using it even if it did. Anything MIOS provides will be software driven. That means if anything happens to stop the processor, the pulse could be stuck on. You are going to need some sort of buffer to step up the output to the 30V required by the Rodgers solenoid (and probably step up the current too). I don't know how to do it but I'd want to use a hardware circuit that delivered a 30V pulse of adequate current based on receiving a 5V logic level rising edge.

Clem, I can see no fault with your schematic but, like you, I am not so good with electronics that I trust my analysis 100%. I would do what you are going to do and verify it by building it.