Ganryu

The Hexboard

66 posts in this topic

Before I get started I must clarify two things. This is NOT my own original idea. Secondly: This is a project I will begin much later. At the moment I'm too much of a n00b to even begin buying parts for it.

First look at this:

http://www.c-thru-music.com/cgi/?page=prod_axis-64

This is a midi keyboard with hexagonal keys. Ridiculously overpriced, but the concept is very nice. I've been thinking about building something similar, but right now there are two obstacles.

A: How do I produce 192 hexagonal keys?

B: How do I aquire switches for those 192 keys?

In terms of capabilities most of the features of that thing are unecessary. I will have no pitch wheel, no mod wheel, no preset buttons.

The only advanced features I need to replicate iare s the single and split functionality.

Single mode: The whole keyboard transmits midi data on one single channel through the OUT port.

Split mode: The keyboard is split in three different sections each one sending data on a separate channel through OUT.

This means I need to be able to configure which part of the keyboard uses which midi channel.

Secondly, this layout means one more unique feature: The same NOTE can be played on different KEYS. That are multiple ways to play the same note. I'm not sure how the midibox will deal with this but look at this example below:

If I hold down one A(1) while rapidly pressing down and releasing another A(2) then the first A(1) will stop sounding because the second A(2) transmitted a note-off message BEFORE A(1) did. This seems like it might create some complications.

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I'm a bit of a n00b as well, but I'll give my 2 cents worth.

As far as getting the switches for the keys, I'd look at places like Mouser or Digikey. They should have plenty of switches for you to look at.

As far as the switch covers (aka Keys), Again I'd look at Mouser or Digikey first. However, I'm not sure about getting Hex shaped key covers. You could investigate something like Ponoko and getting the keys cut from acrylic, but I'm not sure what that would involve.

The rest of your requirements seem more software oriented than hardware.

You might also consider that you might need a few more buttons for your functions, as well as an LCD.

Hope that helps.

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I just ran across this other item from Analogue Haven:

http://www.analoguehaven.com/metasonix/whkb/

http://www.metasonix.com/index.php?option=com_content&task=view&id=41&Itemid=74

It's a DIY Wicki-Hayden keyboard, which seems pretty similar in key layout to the axis stuff. It might help you get an idea of what you need or you could get that and modify the system to work with a CORE. You could probably get some similar functionality in the MB-Studio software.

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Thanks for those links. I've looked around there but it seems hexagonal keys caps are difficult to find.

A friend of me reccomended I'd try contacting a company in china to make them for me by specification. Seeing that I need about a hundred of them this might actually work.

As for the switches, they are EXPENSIVE. 3 euro per switch is like 300 euro for just the switches. Insaaaaane. Add to that the cost of plastic caps and it's quite a hefty sum.

Anyway. This is a summer project, and then I will hopefully have a job and get some more money.

Now for a few questions

Suppose I buy the MIDIO128 and 80 switches and I link all the switches up to the card. Each switch is "assigned" it's own note value. Now imagine that I press the C# switch and hold it down. The C# note-on will be sent by the midi cable. If I release the switch, the note-off message will be sent for C#.

The harmonic table is interesting because unlike other keyboard layouts you can find the same key at different positions. There's a degree of redundancy. This means that while C# is pressed you can actually press ANOTHER C#. This leads to a midi conflict as midi data doesn't transmit whether or not a key is being pressed but rather if it has been pressed down or released. It actually CAN'T tell you anything other than what the midi data tells it it last saw (note-on or note-off).

In the above scenario this means that when one of the C# switches is released a note-off message is sent even if the other C# is still being held down.

Keytrouble.jpg

As you see above the actual length of the note will be shorter if either of the keys is released while the other is held down. This is bad.

Edited by Ganryu

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Thanks for those links. I've looked around there but it seems hexagonal keys caps are difficult to find.

A friend of me reccomended I'd try contacting a company in china to make them for me by specification. Seeing that I need about a hundred of them this might actually work.

As for the switches, they are EXPENSIVE. 3 euro per switch is like 300 euro for just the switches. Insaaaaane. Add to that the cost of plastic caps and it's quite a hefty sum.

Anyway. This is a summer project, and then I will hopefully have a job and get some more money.

Now for a few questions

Suppose I buy the MIDIO128 and 80 switches and I link all the switches up to the card. Each switch is "assigned" it's own note value. Now imagine that I press the C# switch and hold it down. The C# note-on will be sent by the midi cable. If I release the switch, the note-off message will be sent for C#.

The harmonic table is interesting because unlike other keyboard layouts you can find the same key at different positions. There's a degree of redundancy. This means that while C# is pressed you can actually press ANOTHER C#. This leads to a midi conflict as midi data doesn't transmit whether or not a key is being pressed but rather if it has been pressed down or released. It actually CAN'T tell you anything other than what the midi data tells it it last saw (note-on or note-off).

In the above scenario this means that when one of the C# switches is released a note-off message is sent even if the other C# is still being held down.

Keytrouble.jpg

As you see above the actual length of the note will be shorter if either of the keys is released while the other is held down. This is bad.

That would only be true if midi data is generated by the release of one of those buttons. For example if those 2 C# buttons are actually wired to the same points, the connection would only be broken when you let go of the last C# button and hence only one note off signal would be sent.

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That would only be true if midi data is generated by the release of one of those buttons. For example if those 2 C# buttons are actually wired to the same points, the connection would only be broken when you let go of the last C# button and hence only one note off signal would be sent.

That won't be compatible with the split function :(

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I've received a comment from the designer of the Sonome (different version of Axis 64). He claims the plastic button caps are a custom design and that they are pricey when not bought in large quantities. He reccomends using circular button caps instead.

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i bought 200 momentary switches with round caps for under £10 uk sterling from hong kong and that was with free delivery too. as for the caps, its simple you just get a dxf of a switch done i we work out switch size what you can do is this.

get the switches and round caps, have the hex caps lasercut out of some acrylic and also before this they have a 6.05mm hole drilled into the centre. if say the material is 5mm thick have them 2.5mm depth then you can have the switch cap glued into this hex cover cap. this way you get the amount you need made cheaply using a cnc shop that does acrylic.

i will do a quick demo render in solidwaroks for you to show you what i mean and post it later.

11.jpg

22.jpg

Edited by ssp

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Very nice. Thanks for the reply. When you speak of the switches how did you get in contact with that chinese company?

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i just bought them from ebay, it took about 8 days for them to arrive, i always use sellers with an above 97% rating though, the one i used was 100% rated in the feedback.

you could do the same thing with these here: http://cgi.ebay.co.uk/100-pcsTactile-Push-Button-Switch-Momentary-Tact-Caps_W0QQitemZ160380150333

all you do is you make the recess hole under the hex cap a wider diameter accordingly.

Edited by ssp

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i just bought them from ebay, it took about 8 days for them to arrive, i always use sellers with an above 97% rating though, the one i used was 100% rated in the feedback.

you could do the same thing with these here: http://cgi.ebay.co.uk/100-pcsTactile-Push-Button-Switch-Momentary-Tact-Caps_W0QQitemZ160380150333

all you do is you make the recess hole under the hex cap a wider diameter accordingly.

Interesting. While the price is excellent I see a potential problem. It's very difficult to create a square hole. If I make custom button caps I can't drill the holes.

There's one other problem. I have no idea how hard those buttons are to press. They need to be about the same force requirements as a general laptop key.

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Interesting. While the price is excellent I see a potential problem. It's very difficult to create a square hole. If I make custom button caps I can't drill the holes.

There's one other problem. I have no idea how hard those buttons are to press. They need to be about the same force requirements as a general laptop key.

why a square hole???? the switch sits on the pcb inside the case the hole would need to be a hex hole, if you want to make a case similar to the style you posted in the beginning in the link then you would need to get the case cnc cut anyway.

here is a diagram i did for someone else the other week , but it shows the same thing, the green pcb, the tact switch and then the cap showing through the top panel. you would do the same thing however the panel would be spaced a little higher to allow for the thickness of the hex caps.

spacing1.jpg

spacing.jpg

Then when you got it cnc cut out of acrylic you could get it done at the same place as the caps. If you wanted it out of metal then you have several options. the buttons are the same pressure rating as laptop buttons, in fact they dont take much at all, they are momentary tactile buttons or tact buttons as they are also known and require very little pressure, a gentle press is all it needs. how can i compare, press a button on a dvd player etc thats the same sort of thing, behind the cap is a momentary tact button.

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That's not what I mean. I mean the square hole in the button cap itself. To attach it to the switch. If I want to make custom caps later on I won't be able to drill holes for attaching it to the switch.

If you follow the link you posted you will see the button caps have a rectangular hole. This hole will be impossible to replicate if I make my own. I would need to mould them and I don't have the machines for that.

Edited by Ganryu

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Umm, I don't see the problem here. The switch has a round shaft. That's where you attach the cap. You don't attach it to the switch base.

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Umm, I don't see the problem here. The switch has a round shaft. That's where you attach the cap. You don't attach it to the switch base.

No. Follow the link that was previously posted. It's clear the switches have a rectangular shaft.

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Umm, I don't see the problem here. The switch has a round shaft. That's where you attach the cap. You don't attach it to the switch base.

No. Follow the link that was previously posted. It's clear the switches have a rectangular shaft.

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Um, yeh. Use buttons with a round shaft then? And btw you totally can fit a square shaft into a round hole if the hole has sqrt(2)*side_length diameter...

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look the way i suggested is the quickes, and easiest way for you to get the hex caps you want, you recess the green coloured cap into the actual ex cap by glueing it in there, it then just clicks onto the tact switch, that is the quickest, easiest and proven method of doing it. quite a few mboxers have done this method when making custom caps.

so to re-iterate, you get the hex cap made with a small hole drilled into the bottom of it with enough depth to glue the green cap into it flush with the bottom.

when its set you can then click it onto the switch. hey presto there is your hex switch/cap. its really that simple.

you take the cap, measure the diameter of the cap, then with the hex cad file which has got the correct dimension hole cut out in the bottom you take the cap and insert it into the hex acrylic cap. like so

hex1.jpg

once its in there you will have this

hex2.jpg

you can see the green caps rectangle hole? well to connect the now one piece cap which is one piece because you glued the green cap into your cnc cut hex cap you just click it onto the original switch using the original cap hole.

heres a side profile. where the gap is where the glue is.

Assem1-3.jpg

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the other option is to get some tall shaft tact switches and then you just drill a hole in the centre of the hex cap for this to settle into.

however, you want to make a hex control surface similar to what you have linked in the first post, to get the tolerances of spacing right you would need to get them cnc cut and the holes will also need to be cnc drilled, otherwise your not going to get withing 0.001 tolerance. the likely hood of you hand cutting and shaping, sanding these caps and getting to that sort of tolerance would be quite an effort.

what has been suggested is the quickest, cheapest and one of the most used methods for custom caps members use here.the other option is the just glue them to the top of the cap, however your not guaranteed to get them centred at all

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Thanks for your enthusiasm, seriously :D

I know the distance between each button center is 19mm (got this information from the original designer) so the 12mm switches will fit. I guess I'll measure everything out first and then make a prototype version using the switches you linked.

I tried looking around but I could find no switches with round plungers at the same price level.

There's another problem as well in that this will require 192 inputs (if I want to make an exact replica). Afaik the MIDIO128 can only take 128 inputs. How should that be solved?

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The small tacts that are used on the mb6582 for instance are pretty much as cheap as it gets.

More inputs? Matrix.

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also you dont have to have the caps the exact size as the other one, even if they are 1mm over does it really matter? you will still need them custom designed and cut anyway.

at least this way you can be a bit more adventurous with the design etc.

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The small tacts that are used on the mb6582 for instance are pretty much as cheap as it gets.

More inputs? Matrix.

I can't find those for sale anywhere. The official website doesn't actually list the prices and I found only two distributors in sweden, neither which has a website where I can check the price. Do you know how much they cost?

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At reichelt they're 0,11eur each, at mouser has them for the same price iirc.

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Thanks. I found them on Mouser. Couldn't find anything on Reichelt, though. Couldn't figure out if it was possible to show the website in English or not.

I see one problem with the SKHHDTA010 switches used on the MB6582 however. The travel is only 0.25 mm and that's far too short for me. I would prefer 3.0 - 4.0 mm and it seems once you go from the 0.25mm to higher it gets a LOT more expensive.

Btw: In a previous post something called a "matrix" was mentioned as a solution to the lack of inputs on the MIDIO128. What exactly is that? Tried googling it, but alas.

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