latigid on

MIDIbox SEQ new frontpanel idea

301 posts in this topic

Good point about the red. You might be able to block it out with a type of collar or even a gel filter that cuts off ~700 nm.

Anyway, looking forward to more info.

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Just discussing with keycaps direct now. I'm leaning towards the DCS-type of switch as it sits just over 1mm lower and allows the front part to be labelled more cleanly. The angles are a bit shallower.

WK09c.jpg

 

Let's borrow some Sequentix images ;)

400px-P3_completed.jpg

here the switches are squeezed into the minimum spacing, and use quite high caps. There's no panel between switches (same as proposed for my layout).

 

sequentix-p3-742624.jpg

Alternative panel with DSA relegendables?

 

Cirklon looks like it uses DSA (notice the "spherical tops") with bigger spacing

image_33192.jpg

 

this also gives an idea of relative heights; the encoders are sunken into the panel as the switches sit very high up. 

 

A grid of DSA looks like this:

2550uaq.jpg

 

Whereas DCS are much smaller at the top:

Media7-Black-on-White.jpg

 

 

I imagine the cheapest way to go would be to order only one type of cap, so here's the side profiles:

 

5847dd0409b3b_Switchprofiles.thumb.png.d

 

or, the variably angled profile as intended:

5847e0d2aa84b_switchfourrows.thumb.png.5

 

maybe more ergonomic? Or weird?

 

 

 

 

 

 

 

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I'd choose a flat profile simply because then you can have the same switch caps for all switches, no matter where they go. Easier to buy, easier if you need spare parts. Also, I think the way the SEQ is operated, you don't hover your hands over the keys and use minimum movement of your hands as in typewriting, so the ergonomic advantage of an angled profile will probably not matter at all.

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Best DSA keycaps example:
imgext.php?u=http%3A%2F%2Fi258.photobuck
But on ALPS switchs. I didn't find this exact led window for MX stem.

You can find some DCS profile at maxkeyboard and DSC, DSA, G20 and SA  at Pimp My Keyboard but a little bit expensive.
 

Edited by Antichambre

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Pimp My Keyboard is the "retailer" for Signature Plastics -- what I think happens is they supply bulk runs and put the excess on the shopfront. 

The little window is mainly designed for Cherry MX, which have the LED in this location. As said already, this limits the switch illumination to the "north" part (or the "south" if you rotate 180 as some keyboards do). I have a few of the Matias switches (and a "sampler" for Cherry MX) arriving today. The drawings don't show it, but if the switches have enough room on the bottom, I'd like to put a low-profile SMT LED right in the centre. The plunger/slider of the switch is opaque, which should mean the light is diffused around the internals of the switch.

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Talk to the guys behind https://www.modelfkeyboards.com , and get some seriously overspecced keys? :grin:

More seriously, will these boards fit the custom aluminium cases? I've had one waiting for me to gather the other components for a seq.

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Also, for keycaps, is there a friendly laser engraver owner who could experiment with marking? I also wondered about paint black and then using the laser to remove it so the light could shine through the words.

http://keycapdiy.blogspot.co.uk describes DIY dye sublimation, but it's kinda difficult. Perhaps a group but could be arranged with them, though, if it's beyond us?

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No real quote as of yet from SP.

As far as the case goes, I'm doing my best to constrain everything to the same dimensions as Wilba. But it will likely need to be mounted straight on though, as the boards rely on being fixed to the bottom via standoffs. For a sloping case it'd need angled brackets or thick acrylic.

I'm aiming for something thin and flat, maybe a two-piece 3mm alu case where the front is bent around to create a side. Wooden end cheeks for sloping desktop use?

With keycaps, the main driver will be cost (as we are a bunch of cheap-asses :P ). I asked if SP would paint translucent caps, even 4 sides with one layer removed by us. They said it would be expensive, but available as an option. Maybe a spray can and remove one layer like the video above?

Something like this:

2zz7rx5.jpg

is perfect (if only relegendable) but sadly not doable by them. 

AFAIK laser etching is commonly done, but would add to the expense. I'm still keen for a set of blanks with labels printed at home as needed.

 

My switches came, I think I prefer the heavier action e.g. Cherry black over red. The Matias switches are fine but are completely flush on the bottom. They'll need some sort of shine through as @ilmenator suggested.

 

 

 

 

 

 

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Hello,

There's a custom option for shine through at Maxkeyboard
custom-bklt-key.jpg?t=1469431152Max_Custom_Backlight_Keycap_2.jpg?t=1454
but it's expensive, cheaper with bulk order maybe.

BR
 

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That stuff looks excellent! Personally I would think it the wiser to ditch the Heidenreich-case, as it was only available in a couple of bulk orders with long wait times, rather expensive and, well I don't like it cause the edges are to pointy and you still need to hotglue everything together to make the parts stop rattling. The real step forward of the suggested design is, I think, its simplicity. By offloading all the labelling onto the switches, the front panel gets so simple one might even be able to DIY a neat-looking version with a hand drill, a file and a jigsaw (and build the rest of the enclosure out of a few pieces of MDF or wood, similar to the case =FFW=> had constructed for the sequencer he offered for sale in the flea market recently). I imagine this would boost the appeal of this awesome musical instrument for a lot of potential users.

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The heidenreich case was never required. Being compatible with it surely only requires that the boards don't end up too big to mount behind the given panel space, which doesn't seem like too onerous a requirement?

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I must admit to being slightly confused - is this because the keys get in the way of bolting to the front panel? Or are they just deeper to the point of causing issues?

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If you read back, there is no front panel between the keycaps. This is fixed by the 19mm spacing for switches and keeping a 3U height. It's quite commonly done on mech keyboards and the P3 shown above. But it means the boards can't hang off the front panel, at least not where the switches are. It could be done another way, e.g. angled rails or chunky acrylic. But at some point you need to make up that angle as screws can't go around corners.

Maybe it makes sense to go for 4U for extra breathing space. 

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The images I saw seemed to have space at the left and right edges? Could the bolts not go there, perhaps with reinforcing struts behind to prevent flexing?

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2 minutes ago, lis0r said:

The images I saw seemed to have space at the left and right edges? Could the bolts not go there, perhaps with reinforcing struts behind to prevent flexing?

Maybe something like that, yes :). Some sort of interior panel or mounting rails would also give valuable room to mount things like the Core/AOUT/line driver etc.

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10 hours ago, lis0r said:

The heidenreich case was never required. Being compatible with it surely only requires that the boards don't end up too big to mount behind the given panel space, which doesn't seem like too onerous a requirement?

Yes, you are of course right, the case wasn't required, it was just the easiest way to a professional looking device. But at 128 Euro plus 115£ for the front panel from thebeast.co.uk plus however much the back panel cost, the case was by far the biggest cost factor in the build. A cheaper solution would be better. The screen printed metal case with wood sides for the Mutable Instruments Ambika i bought cost 110 Euro altogether incl. shipping. Might even be worth to ask Adrian, the guy that designed it, if he would be up for making one for this project. 

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Sure, more options are great. It'd be nice if it wasn't made incompatible, though, especially if it doesn't result in a significant cost difference. It'd be nice if the boards enabled users to express their design preferences, rather than mandated a cheap end result.

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3 hours ago, u-link said:

Yes, you are of course right, the case wasn't required, it was just the easiest way to a professional looking device. But at 128 Euro plus 115£ for the front panel from thebeast.co.uk plus however much the back panel cost, the case was by far the biggest cost factor in the build. A cheaper solution would be better. The screen printed metal case with wood sides for the Mutable Instruments Ambika i bought cost 110 Euro altogether incl. shipping. Might even be worth to ask Adrian, the guy that designed it, if he would be up for making one for this project. 

I think it was always intended to provide a case for the SEQ -- absolutely one's required if you're playing anywhere other than your attic (hint: @Hawkeye)! It's something that's always puzzled me, as the case is important to every project, but here was almost an afterthought. There've been enough disasters with money going missing that some folks are understandably a bit wary.

I'm in contact with Adrian now and again; he's a nice guy with lots of skills and contacts. Another option is Protocase, like I did with the BLM16*16+X. That one was complicated though as it required studs, milling, threading and precision bending. Great quality and accuracy though. 

 

3 hours ago, lis0r said:

Sure, more options are great. It'd be nice if it wasn't made incompatible, though, especially if it doesn't result in a significant cost difference. It'd be nice if the boards enabled users to express their design preferences, rather than mandated a cheap end result.

I get what you're saying about reusing the existing parts. I will try to maintain the sizes, but we've gone and squashed a whole extra row of buttons in, and they're quite a bit larger than the TL series. In the end, this is a new project and if things have to change, they will. Just thinking about the idea of metal reinforcement, the panel will be mostly holes and cutouts, so it won't be very strong. 

585083403fde7_mechSEQroughpanel.thumb.PN

(~$70 for one-off).

 

I'm not discouraging anybody, so please keep up the opinions. Better still are solutions to things like mechanical strengthening, mounting options, part suggestions etc.

If people want a cheap SEQ, they should stick with the Wilba version. The switches and keycaps alone will likely cost more than the "parts kit" for the former. But I've tested the Matias switches and they light up quite nicely. I'll to look at methods of reverse-mounting LEDs of decent brightness. 

 

 

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Good diagram. If strength of the front plate is a serious worry, it seems like plate mounted key switches would be better than plain PCB ones?

I know this heresy here, but if depth is getting to be an issue, how about a pure SMT all-in-one core & I/O board? Soldering an STM32F4 might be intimidating to a newbie, but it doesn't look as if it'd be hard.

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Thanks, it's not 100% accurate but gives a general idea. Now imagine if the north and south edges were bent 90 degrees and formed a U-shape. This adds significant strength to the metal and could allow for panel mounting. 

The switches are indeed already plate-mounted (using the same PCB that holds the encoders and aux switches). Still, the plate/PCB needs something to fix to! My experience with the BLM is that you need mounting points at least every 75mm or so. The smaller PCB in the current work will help, but it needs consideration. 

I think I'd be okay with soldering an STM32F4, but you lose the valuable ST-LINK part, so need an FTDI programmer or similar. These would put the project out of reach for many people. Let's see how the jigsaw puzzle pans out.

Heh, I think you can use the Discovery Board as a programmer :)

 

More edits: Discovery has an okay power regulator and an ESD snubber for USB OTG, and the whole thing is very affordable. If at all possible I'll try to keep using it. 

 

Edited by latigid on

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Presumably that'd be two U shaped switch plates per unit with 24 cherry shaped holes as well as any mounting holes. Are there any companies that specialise in making cherry switch plates, or would we have to engage the services of a general metal workers? They sound expensive!

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I don't have good chops at 3D CAD, so you'll have to read my explanation :) The main take-home is that the mounting plate is not the front panel!

Let's consider a U-shaped case. The top layer is ~3mm aluminium or maybe thinner steel. Next down is the "plate," which has lots of square-ish cutouts. It also carries the encoders and other bits you'll see on the panel. Below this is another PCB where the switches mount, also the BLM and shift registers. There's two lots of 8*4 per build. Below those are whatever PCBs are needed to complete the unit: Core, I2C, maybe AOUT, though I expect a line driver can be added. 

To the north side of the PCB assemblies sit the LCD/OLEDs and under them newly designed MIDI IO ports. They'll have 8 DINs on each and can be wired as 4 I/4 O or 8 O.

I have some ideas to use the space on the left to get the SD/USB out. 

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Regarding the inner plates, I was reminded of the C64 keyboard, where tiny screws were used to mount the PCB to the plate, then the plate mounted to the front panel at the edges. Is there any way this could be used to simplify the internals.

USB%2Bkeyboard%2Bcontroller%2Bon%2Bback%

C64-keyboard.jpg

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I think I get what you mean: extend the "plate" so it can be fixed past the main PCB sitting below it? I think that would add some height to the front panel? Also the displays get in the way. I'm not expert on mech keys, but I think the main purpose of the plate is to reduce lateral wobble in the keyswitches. With some extra standoffs between that and the main board it should add some rigidity, but the major flex point will be right in the centre of the lower one. 

It'll have to be a "best guess" approach for the initial run and see how we go from there. Over-engineering is a good idea. :)

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