Projectdescription:
In Germany we have a lot of historic (pipe) organs. Many of them have a lot of different timbres which are controlled by registers: (Registerzüge, in german)
Ive been asked to automate this technology in our local church. The wish is to have a control panel with different profiles, one for each organist (organ musician), so they can easily swap between their personal favourite options.
Problem:
There are at least 60 to 90 different leavers for the different registers and feedback of the active registers is also wanted (probably in form of LEDs).
That means I need a minimum of 250 in- or output pins to get all the states of the registers to my Controller.
Would you recommend using an Arduino with some sort of Bus System for all the leavers?
My Ideas:
I2C bus on the digital Pins? (With software emulated I2c bus libs)
SPI bus in some sort of MasterSlave different arduinos which send arrays to the Master Arduino.
Any other, hopefully much better Ideas are appriciated
I2C is a possibility, but distance could be a problem. You may get i2c signals to travel 2m, but any further will require repeaters.
An i2c multiplexer may also be useful, and could act as a repeater also.
For large numbers of buttons and LEDs, arrange them in a matrix to reduce the number of inputs and outputs needed. For example, 16 inputs can scan a matrix of 64 buttons.
In addition to the chips mentioned by @J-M-L , take a look at:
The current standard is a SPS (PLC Simatic/ Wago) Solution (costs about 6000€) but its simply too expensive.
Another reason to redesign that system is, i dont want to have one seperate cable for every stop and or LED. I am more than convinced that there has to be an easier solution with more user friendly access.
It might even be possible to design this project as modular as possible for other organs.
Indusrial standard at my work at VW would be Profibus / Profinet for large application.
Maybe ModBus could work with the RS485 idea. However I personally have not worked with that yet.
You wouldnt believe me if I told you thats the current solution in many organs here in Germany...
Id love to show you some pictures
Even tho possible, i would really like to avoid that. Id rather have the smallest amount of problems possible with the hardware:
You know -> Church = Rough conditions for electric systems.
A very long time ago the company I worked for designed similar system. That is, we had to indicate hundreds of outputs separately, each with an LED across shelves in a very large room and also read a push button corresponding to each LED. I would suggest the same technology we used then since it's just as effective: shift registers as someone noted.
By "daisy-chaining" or cascading the registers you can get around the problem of long control signal distances since each registers will buffer the signal of the upstream one. Using CMOS, you can drive it at 12 volts and improve the signal integrity due to greater hysteresis levels.
No devices come to mind immediately, but if I have time, I'll look through an old CMOS databook later.
Maybe I missed the answer to this question: I can see from the picture that the registers are manually activated by pulling/pushing them to the desired positions. Is there second method to control them, pneumatic cyinders or electrical solenoids?
Indeed. That sounds like a lot more trouble than a bunch of push buttons and LEDs. There may be space constraints too, for the solenoids, steppers or whatever the mechanism is.
IF there is an off the shelf answer that costs too much, I wonder how much your test system will cost or are you going to disable the church organ for the entire time you are testing? And will you need to use the church organ between tests?
Thank you for your awesome contribution. Sounds exactly like the system I might be interested in.
Do you have any references? I am going to read a little bit more into that.
Ive designed a system for electromagnetic activation. (Stuff I actually do at work :D)
There are reed contacts build in, that are used for the determination of the final position.
A lot of other churches use toggle switches, which are pneumatic, mechanic or even electric. For all of these systems are relatively cheap options already on the market.
In this specific project i want to design a User Interface in which you can safe different and personal combinations of the registers/stops.
The coding should'nt be a problem, however I want a relativ rebust and simple system so nobody really has to interfere with it in the next few decades.
Repairable, affordable (especially for churches) and user friendly are my personal ambition!
That system is already built, space saving and currently in testing phase. So no worries!
As I mentioned before its an electromagnetic system.
The actuator is controlled by a simple 5V or 12V relais (whatever is needed to supply the rest of the circuit)
I can give you more information on that topic if needed. However I would open a new topic for that, because its not corresponding to the current topic.
Id like to thank you anyway for your prudent and forward looking thinking!
The off the shelf solution in Germany is currently a PLC system with a WAGO PLC.
You have to wire every cable for every sensor, register, switch, LED etc sepperatly.
So that solution is too expensive (WAGO PLC+Modules alone like 3000-3500€, Everything together+ installation costs around 10000€) and for me personally too laborious to use.
The next thing is, that a PLC is absolute overkill. Its sitting there most of the time and just waiting for User Input.
The switching process is not really timing dependent. Thats why I thought a microcontroller of any sort is more than sufficient for this task.
All in all I am convinced that I can get away with around 3000€ to 4000€ for all together. However that remains to be seen.
The church organ will only be disabled for the installation. All testing is done with my testing rack at home. The testing rack consists of parts of an old organ my father once "adopted"
He is a proffesional organ builder and the reason why I am planning a system for our local church.
