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Lighted Stop Action with a Twist

Building organ consoles for use with Hauptwerk, adding MIDI to existing consoles, obtaining parts, ...
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Coenraads

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Lighted Stop Action with a Twist

PostFri Aug 27, 2021 1:48 pm

Elsewhere on the HW Forum,

viewtopic.php?f=1&t=19935

it has been suggested that if one has a lighted stop action with more stops then are needed for a sample set, it would be nice if there is a way of indicating which stops are enabled (activated) and which stops are not being used. A forum member,  engrssc, has the rather clever idea that the LEDs for enabled stops all be made to glow dimly and only come on fully when the stop is ON. Since I have a decoder driver on my website already, I went ahead and modified it to have the behaviour just described.

https://sites.google.com/site/casavanto ... th-a-twist

Here is how it works: When a stop is turned on, its number is stored in an array that keeps track of all stops that are enabled. These stops are then turned on and off rapidly with about a 20% duty cycle causing them to glow dimly until they are turned ON, when they glow fully. Turning the stop OFF causes it to revert back to the dim state.
The code can be loaded onto an Arduino Mega which is then connected to a keyboard (channel 1) to see how this works. You will need to connect some LEDs (+resistors) to the outputs (pins 2 to 68) to see it in action.
When a new sample set is loaded, the decoder is reset by clearing the array that keeps track of enabled stops. For testing purposes only, I have arranged it so that pressing top C clears the array. This function could also be assigned to a "console reset" button or alternatively, it could be triggered automatically when a new sample set is loaded. If one now pushes a special general piston that has been programmed with all the stops in that sample set followed by a general cancel, all the enabled stops will glow dimly while stops not available will remain dark.
I think this is an excellent way of getting around having to use a touch screen if you already have a console with a multiplicity of stops and a lighted stop action.
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larason2

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Re: Lighted Stop Action with a Twist

PostFri Aug 27, 2021 3:32 pm

That's a very clever idea, thanks for sharing! This lets an LED be used with a digital pin instead of requiring an analog one.
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Coenraads

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Re: Lighted Stop Action with a Twist

PostSat Aug 28, 2021 10:57 am

Yes, that's right. Basically I am pulse-width-modulating the digital pins. And since it takes only 3 microseconds to switch a digital pin, this is quite feasible.
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engrssc

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Re: Lighted Stop Action with a Twist

PostSat Aug 28, 2021 12:11 pm

I might add this project is still a work in progress, but as is, works well as John mentioned. I have been using a KEYESTUDIO Mega Advanced 2560 R3 Board as the decoder for testing.

https://www.amazon.com/gp/product/B07Q8F414X/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

This board has been able to power all 64 high efficiency LEDs (with a series 1K, 1/8W resistor) simultaneously with no problems.

The idea behind this is to be able to use generic labeled lighted stops (in my case - lighted drawknobs). When a sample set organ is initially loaded, it's stops can be assigned (using auto-detect) to these generic appropriately labeled console drawknobs. It is possible that all of the sample set's stops may not be used. In that case, only the assigned (for that particular sample set) will glow (light) dimly. Any unused console drawknobs will be dark (unlit). This gives the organist an indication which stops (for the selected sample set) are available.

When a stop is drawn, either thru using a combination action piston or by hand registering, that stop will change from dim to bright and of course be playable.

When another, different sample set organ is selected, the above arrangement will be reset (cancelled). Then according to the way this (new/latest selected) sample set stop's have been assigned to the console's "generic" stops will be substituted.

We are trying to address in part the labeling issues between various sample sets without the need for using other external means (Launchpads, etc). In one case, a client used small "sticky" labels for a second most favorite organ. The primarily used sample set organ used the originally installed drawknob labels. Sticky labels - not good. :roll:

BTW, the same (above) can be used with lighted stop tabs - using LEDs. If the stops are using incandescent lamps, a driver between the Arduino and the lamp would be necessary due to the higher current draw of. Incandescent
lamps,

The Arduino board communicates with Hauptwerk via the MIDI Input and MIDI Output interface.

Rgds,
Ed
Last edited by engrssc on Sat Aug 28, 2021 9:22 pm, edited 1 time in total.
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engrssc

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Re: Lighted Stop Action with a Twist

PostSat Aug 28, 2021 6:51 pm

An answer to a question as to how to change existing drawknob labels (which may not be a perfect solution for everyone). I did this process a while ago with good results:

Image

Most drawknob "heads" are fastened to the drawknob assemblies with a tiny set screw on the bottom of the drawknob head. You can use a 5/64 Hex Key Allan Wrench:

https://www.ebay.com/itm/293067434136

After removing the head, the existing label can be (carefully) lightly sanded so that a replacement generic label can be substituted. Alternately depending on the drawknob configuration, you can purchase new blank stop faces from Matt at

https://www.mcnsystems.com/about.htm

For replacement labels these Product OL1025CL - Clear Gloss Laser - 1" Circle Labels can be used

https://www.onlinelabels.com/products/ol1025cl?src=mp-449

Tip - you can request from OnLine Labels up to 3 free sheets of a given label as a sample.

https://www.onlinelabels.com/samples

Also available from On Line are free printing templates for making custom labels. I used a tweezer to assist in placing a label. These labels are very durable but if desired later, can be peeled off and removed from a stop head face and be replaced.

Additionally there are small rectangular labels for stop tabs and/or couplers:.

https://www.onlinelabels.com/products/ol4904cl?src=mp-449

You obviously can choose the font, type size and color for your custom labels. Yes, a bit of work, but quite doable. Esp since many Hauptwerk folks are into making custom "product improvements" . 8)

Rgds,
Ed
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mdyde

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Re: Lighted Stop Action with a Twist

PostSun Aug 29, 2021 3:42 am

[Topic moved here.]
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.
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engrssc

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Re: Lighted Stop Action with a Twist

PostMon Sep 06, 2021 3:19 am

I have added to the project - each sample set selector button both selects an organ (sample set to load) as well as provides a single (array) reset "command". All of the reset functions from the second piston output(s) from all of the selector buttons (in parallel) produce a single reset output. This reset pulse "clears the way" prior to a new sample set being loaded. To accomplish this (paralleled) reset pulse requires four mouse clicks. John has provided a reset pin for the Arduino decoder sketch. Quite straight forward. See John's explanation "How this works" above.

https://forum.hauptwerk.com/viewtopic.php?f=15&t=19969&p=149879#p149765

If you've followed this dim / bright lighted stop project you probably realize the biggest time thing would be reloading each sample set and matching the sample set stop names with the appropriate available console stops. In some cases,
there may be a need to re-label the console stops to make them more generic. At best there will need to be some compromises which not everyone wouldn't find acceptable.


BTW, thinking of possibly adding a sample set selector (rotary) switch with a single piston to "make it happen".

https://www.syndyne.com/products.php?id=91

Rgds,
Ed

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