TK.

MBBLM schematics and PCB discussions

118 posts in this topic

I opened a separated forum section for discussions about the MIDIbox BLM, since this project is not tightly coupled with the MIDIbox SEQ project, but can also be used standalone.

 

Schematics:

 

 

 

I'm not planning to layout the PCBs by myself, but volunteers already evinced to help out! :)

Just start to coordinate your efforts here.

 

Some input from my side:

 

as you know I created the BLM16x16+X on veroboards (link to Gallery)

For me this was less time consuming than layouting and ordering PCBs, especially since at the time where I started this project it wasn't clear if the SRIO hardware will work stable - I used tricks that I never tried before to reduce the chip count.

With the prototype I've proven that the concept is working, so that I can release the schematics for layout.

 

If somebody really plans to build the circuit on verboard like me instead of waiting for the PCBs, be warned that you need some soldering experience, a lot of time and especially patience!

 

It took me ca. 40 hours to complete the BLM16x16+X on verobards.

It was hard work and I would never do this again! ;)

With PCBs I expect only ca. 15 hours work, a more stable construction, and less risk for wiring errors (-> newbie friendly).

 

My costs so far (all parts ordered at Reichelt):

 

LED 5 RG-3 Duo-LED, 5mm, 3pin, rot / grün 300 45,00 Euro
TASTER 3301B Kurzhubtaster 6x6mm, Höhe: 9,5mm, 12V 300 30,00 Euro
1N 4148 Planar Epitaxial Schaltdiode, DO35, 1 300 6,00 Euro
To speed up the wiring I used "verowire" (german: "Fädeldraht"), and I used 7 x "H25PR200" veroboards which won't be required for a PCB based solution, therefore they are not listed in the list above.

 

I strongly recommend you to order 300 LEDs/Buttons/Diodes as well although only 289 are used.

E.g., at my order Reichelt only sent me 296 LEDs instead of 300 - good that these were spares!

I had the remaining components for the 5 BLM_SCALAR modules + 1 PIC based MBHP_CORE already in my "personal stock". If you are interested in the part numbers you will find the references at the MBHP_DIN and MBHP_DOUT page.

 

 

Layout suggestions:

in the last months I got some mails about how a BLM layout could look like, and this only showed me that it will be very hard to find a universal solution.

 

E.g., somebody proposed to prepare the layout for different button footprints.

My comment: due to the increased amount of drill holes this will lead to much higher costs for everybody.

 

Somebody else proposed to use RGB LEDs instead of Duo-LEDs, since they are cheap at EBay

My comment: this will increase the costs for everybody again, and it will be hard to find the same LEDs at such a high amount.

E.g., consider only 30 people would like to join the PCB order - they would have to find ca. 8700 RGB LEDs from the same seller, or some of the people would have to buy more expensive RGB LEDs from a regular electronic shop.

Another point that needs to be considered: for the BLM16x16+X I already chained 15 74HC595, MIOS8 supports 16 DOUT shift registers maximum. Increasing the amount of DOUT registers to control the blue LEDs will lead to difficult software changes.

Third point: RGB LEDs draw much more current, especially more than Red/Green LEDs. Blue LEDs probably require additional transistors (or ICs) as source driver.

The additional 74HC595 and these source drivers will require a different BLM_SCALAR module - again it doesn't make sense to bring this into an universal layout that is intended for my original project.

I'm sure that most people will be happy about a cost efficient solution with Red/Green colour LEDs (like me).

 

Buttons: this will also become a difficult topic.

I will use these ones:

But I'm not sure if this construction will be stable enough.

A better solution could be the usage of the same buttons and caps that where used on Wilba's MBSEQ frontpanel.

 

Partitioning the PCBs:

the SRIO and BLM circuit has already been separated. The SRIO boards are stacked under the BLM board.

It has to be considered if a huge BLM board is better than splitting the circuit into two or three parts (think also about the reduced shipping costs...)

 

For the BLM_SCALAR boards I recommend separate modules for each 16x4 matrix, because it is too difficult to plug the board into more than 2 large dual pin header sockets.

Note that this approach would also allow you to use the same BLM_SCALAR boards for different BLM board designs!

 

Matrix routing:

can be changed if really required.

The firmware has to be adapted accordingly (changes are difficult for somebody who never worked with forward/backward matrix transformations before, see main.c)

Therefore changes in the routing are only recommended for people with software programming skills.

 

Additional features:

I will add 6 faders to my BLM16x16+X, because I find it important to get the possibility for manual sound changes with one hand, while sequences are changed with the other hand (therefore it's better to have the close to the matrix).

The firmware is prepared for up to 8 pots/faders.

 

More informations/suggestions on request.

However, my hope is that this will become a community project where experienced people will help out and where I don't need to support you that much!

I could be interested to join the PCB/kit bulk order as well! :)

 

/Update Oct-2015: after 5 years finally we got a kit created by Latigid On!
-> http://midibox.org/forums/topic/19736-blm-16x16x-build-guide/

 

/Update Jan-2016: new firmware blm_scalar_v1_1 can be downloaded from http://www.ucapps.de/mios_download.html

It contains prebuilt hex files for various hardware configurations:
  o project_without_ain.hex            -> without AIN enabled (use this if J5 pins not connected to ground)
  o project_with_4_mapped_ains.hex     -> for Latigid On's BLM PCB layout, only 4 faders used
  o project_with_4_unmapped_ains.hex   -> AIN pins are mapped 1:1
  o project_with_8_mapped_ains.hex     -> for Latigid On's BLM PCB layout if 4 faders + 4 extension AINs are used
  o project_with_8_unmapped_ains.hex   -> AIN pins are mapped 1:1

 

 

/Update Jan-2016: if you are using a PIC18F452, it's required to change the PIC device configuration while flashing the bootloader: the brown out reset level has to be changed from 4.5V to 2.7V as shown in this picture:

blm_scalar_pic18f452_config.png

Otherwise PIC could be reset sporadically (depending on the number of enabled LEDs) because the voltage level could fall below 4.5V!

This change is only required for PIC18F452, other pics (such as PIC18F4620 and PIC18F4685 will work w/o this change).

Unfortunately this change can only be done with a PIC programmer. Please contact me for the case that you don't own a PIC programmer. I could send you a replacement PIC18F452
Alternatively use a PIC18F4620 or PIC18F4685 if you own one

Best Regards, Thorsten.

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For those who haven't seen this thread: I have volunteered to design a PCB and matching panel. There are a few example pictures further down the thread.

Some notes:

- I intend to design it in a way that will fit in a single chassis with Wilba's control surface PCB. This is my ideal scenario, as I already own this PCB and I haven't paid for front panel yet. It will however be simple to offer a modified version for standalone use. If I can find a free DXF editor I'm comfortable with (or get Inkscape's DXF export to work) I'll provide DXF files for those who don't want to use Ponoko.

- My intention is to use the same button(TL1100F160Q)/cap(611-PEBK)/Bi-LED(859-LTL1BEKVJNN) combo as in Wilba's CS (mouser part numbers). I will consider adding additional footprints to the board, but will keep expense and usefulness in mind. Personally, I can't afford ready-made illuminated buttons of decent quality. Ideally I'd like the quiet ones described here: Seems that group buy died unfortunately.

- I want my BLM to align with the buttons and encoders on the control surface. People who want a standalone BLM may want the 'square' format. I propose a BLM PCB that is (or can be) split down the vertical centre. This will allow both layouts. From looking at the schematic, each 16x4 section will require 31 wires to jump the gap.

- I propose to have the BLM_Scalar module integrated on the button PCB. As with the above suggestion, I'm assuming this is feasible but I'm not experienced in such matters.

- I have no experience with actually producing PCBs or panels. I have gotten the hang of both KiCad and Inkscape, so I think I will be able to achieve this with a few pointers from more experienced people. If any experts wish to take up this project, I'm happy to defer to them.

Please offer your suggestions! I'm stuck on a 13" screen until the end of the week, so probably won't start work until then.

:)

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Hi Guys !

I am in

LED : i have a friend who often goes to China and can get them on the market. I asked him 500 RGB Led and he came back within 1000 (free shipping, it was in his case)

having 10000 would not be hard (it is rather small in fact) . SMD would be a ggod alternative. We can negociate a good price as he deals with factories.

I have done an RGB 8x8 buttons matrix without the need of transistors.i did not notice all the requirements with the SD, SC, all the shift registers necessary, etc ...

Buttons : from my experience, plastic buttons are clicky. Rubber buttons like those in the monome are "middly" good. Those from Sparkfun are rather good.

The guy who own livid sells 8x8 matrix buttons. for a big GB, he could make discount. A friend of mine own a plastic factory. I will talk to him about rubber buttons to have an idea of costs.

Personnaly i would prefer all in one pcb (shift registers soldered on the back), even if it is SMD (it isn't hard to solder if you have Flux and a good video demo).sandwiched version with screws.

I designed in Frontpanel Designer and Eagle http://4colors.free.fr/4colors/Machines/Pages/The_Rainbow.html

PS : if we can make an MAXMSP patch like "nonome", lots of people could be interested

Edited by julienvoirin

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- I want my BLM to align with the buttons and encoders on the control surface. People who want a standalone BLM may want the 'square' format. I propose a BLM PCB that is (or can be) split down the vertical centre. This will allow both layouts. From looking at the schematic, each 16x4 section will require 31 wires to jump the gap.

In this case it could be a good idea to change the matrix structure to 8x8 instead of 16x4.

This would give us 4 quarters, and between these modules there are only the SRIO connections to BLM_SCALAR modules.

It would require some firmware changes, but so long only a second variant is required to simplify the HW, it would be ok.

- I propose to have the BLM_Scalar module integrated on the button PCB. As with the above suggestion, I'm assuming this is feasible but I'm not experienced in such matters.

This isn't feasible with a double layer board, because there are too many crossing traces between buttons and LEDs.

We would need to use a multi layer PCB, and thats expensive.

Personnaly i would prefer all in one pcb (shift registers soldered on the back), even if it is SMD (it isn't hard to solder if you have Flux and a good video demo).sandwiched version with screws.

dito, same problem with crossing traces.

Buttons : from my experience, plastic buttons are clicky. Rubber buttons like those in the monome are "middly" good. Those from Sparkfun are rather good.

The guy who own livid sells 8x8 matrix buttons. for a big GB, he could make discount. A friend of mine own a plastic factory. I will talk to him about rubber buttons to have an idea of costs.

Please identify the costs before this discussion goes into the wrong direction.

So, we have already three plans that contradict each other - are there other opinions; how should your BLM16x16+X look like.

(I will start a poll once enough frontpanel ideas have been collected)

Best Regards, Thorsten.

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Using your Ikea case idea the approximate size is 30 cm EDIT: by 40 cm. So approx. 7 rack units, plus a Wilba/TK SEQ is 10. That's quite a bit of real estate, and I'm wondering whether the SEQ belongs in the rack (MIDI'd to your synths) and the BLM on a keyboard stand/ table/ hand-held as a real performance instrument.

Plus, it's gonna be battery powered and WLAN MIDI'd right? ;)

I'd say people will have a lot of opinions on which buttons to use, my humble suggestion is to keep the layout as general as possible so peeps can choose. SPST tact switches usually have 200 mil pin spacing, correct?

Edited by latigid on

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TK. Just wanna say great work. Did you like your circular rubber button matrix idea that you were testing?

To everybody.

I would think that everyone would of course want a pcb design but what would that cost roughly? Anyone? Vero board is a lot cheaper in this case right? Either way you look at it, it will be a one time job for most of us and 40 hours of build time seems right for something so massive. If a pcb board gets broken down into sections will that reduce the cost at all? Being able to use self made panels and common switches/buttons (round type) would get a lot more of these babies in action.

Concerning a panel.

To keep costs down I think a simple sheet metal panel of whatever type only cut to size with holes drilled by yourself for round switches and round leds would be a very cost effective panel solution. If you have access to someone/equipment that can cut a big and simple square piece of metal. From then you just get a ruler out and pencil you drill holes and get drilling. The you could write in sharpie, label maker or use the adhesive printing paper technique to get your text on the panel.

TK.

When you get a chance could you possibly take a close up picture of the wiring on the back of the veroboard and add some text to describe what is where and where its going? I never figured out the button matrix for my MBFM because I don't quite understand certain aspects of schematics. If this seems to be a waste of time please disregard this last paragraph. I am feeling cheap right now and wanna get excited making a veroboard version.

Regards,

echo

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Using your Ikea case idea the approximate size is 30 cm EDIT: by 40 cm. So approx. 7 rack units, plus a Wilba/TK SEQ is 10. That's quite a bit of real estate, and I'm wondering whether the SEQ belongs in the rack (MIDI'd to your synths) and the BLM on a keyboard stand/ table/ hand-held as a real performance instrument.

From my experiences with the BLM16x4 that I built into a rack case a separate BLM that sits flat on the table is definitely better than a rack mounted option!

TK. Just wanna say great work. Did you like your circular rubber button matrix idea that you were testing?

I haven't got the new rubber button order yet, and will need a frontpanel before I'm able to mount them.

Before other people are trying this, I recommend to wait for my tests.

I would think that everyone would of course want a pcb design but what would that cost roughly? Anyone?

I assume ca. 50 EUR - no?

Vero board is a lot cheaper in this case right?

You would save 35 EUR, but would get a robust and easy to solder solution in return.

Either way you look at it, it will be a one time job for most of us and 40 hours of build time seems right for something so massive.

Maybe my warning wasn't clear enough: don't do this at home kids! ;)

If a pcb board gets broken down into sections will that reduce the cost at all?

Probably yes

When you get a chance could you possibly take a close up picture of the wiring on the back of the veroboard and add some text to describe what is where and where its going?

See http://midibox.org/forums/index.php?app=gallery&module=images&section=viewimage&img=279

The cables are so thin, and the circuit is so large that a picture doesn't really help.

The schematic http://www.ucapps.de/mbhp/mbhp_blm_map.pdf gives you a better overview, but if it doesn't make sense to you, it's definitely better to wait for a PCB, because otherwise chances are high that you've to spend much more time to find and fix wiring errors!!!

Best Regards, Thorsten.

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I assume ca. 50 EUR - no?

You would save 35 EUR, but would get a robust and easy to solder solution in return.

Well if its only that much I wouldn't mind hearing from US and euro distributors. I am just concerned if it is decided to go with Wilba's rectangular buttons from seq run because that would mean a professionally cut panel would be pretty much required instead of drilling holes ourselves using circular buttons/leds if we wanted that option.

Maybe my warning wasn't clear enough: don't do this at home kids! ;)

Yes Midi Papa ;)

Regards,

echo

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I am just concerned if it is decided to go with Wilba's rectangular buttons from seq run because that would mean a professionally cut panel would be pretty much required instead of drilling holes ourselves using circular buttons/leds if we wanted that option.

The same button caps need not be used with those buttons - perhaps there are circular ones available?

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The same button caps need not be used with those buttons - perhaps there are circular ones available?

hi all,

i used these ebay tact switches on wilba's seq cs pcb.

http://cgi.ebay.com/100pcs-Tactile-Push-Button-Switch-Momentary-Tact-Caps-/370371926198?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item563be318b6#ht_806wt_908

round = only one colour, blue.

also available with square tops and 5 colours.

:thumbsup:

post-3719-12741539139_thumb.jpg

post-3719-127415399783_thumb.jpg

post-3719-127415403511_thumb.jpg

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I'd prefer a monomeish solution with rubber buttons. To size it like the sequencer LCDs sounds like a good idea.

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If it were 2 pin duo led's (example http://www.betlux.com/product/LED_lamp/Dual%20Color%20LED(2Pins)/BL-L517.PDF )

Then it was easy to use the switch with transsparent cap.

Is a 2 pin duo led even possible?

Yes, but it's more like two diodes arranged back-to-back. Unfortunately you can't then use both LEDs at the same time, so you couldn't have a third "orange" state. The addressing of each LED state becomes a bit tricker too (I think).

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TK, do you think 3mm LEDs would work alright with your illuminated button concept?

I see a possible configuration:

Switches: E-Switch TL1105SP - 7.5mm to top of actuator.

LED: 3mm duo as used in Wilba's CS order. Mouser: 859-LTL1BEKVJNN - 6.7mm min height.

Button caps: There is a matching round cap for those who want to drill their own panels, Mouser: 612-1R-BK, and also other shapes.

It would also be possible to do a solution like TK's cheap illuminated buttons. Also I'm thinking it might be possible to use the silicon sheet, and have nice looking laser cut acrylic glued on top as buttons instead of the rubber feet. This would hopefully give a nice feel.

:)

What's everyone think?

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In this case it could be a good idea to change the matrix structure to 8x8 instead of 16x4.

This would give us 4 quarters, and between these modules there are only the SRIO connections to BLM_SCALAR modules.

It would require some firmware changes, but so long only a second variant is required to simplify the HW, it would be ok.

TK, do you plan to create this schematic?

I have my new monitor now, I will start PCB and frontpanel design work soon. I'll start with the BLM_SCALAR modules.

:)

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Design is progressing..... though I haven't gotten to the hard part yet. :frantics:

post-6793-127739439007_thumb.jpg

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Looks good so far!

The 8x8 based variant would look similar, but currently I don't have the time to draw the schematic.

You would create a schematic anyhow, so let's save this effort - I will explain it instead.

If LEDs/Buttons are numbered this way:

EC1 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16

EC2 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 B13 B14 B15 B16

EC3 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16

EC4 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16

EC5 E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 E13 E14 E15 E16

EC6 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16

EC7 G1 G2 G3 G4 G5 G6 G7 G8 G9 G10 G11 G12 G13 G14 G15 G16

EC8 H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 H11 H12 H13 H14 H15 H16

EC9 I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 I11 I12 I13 I14 I15 I16

EC10 J1 J2 J3 J4 J5 J6 J7 J8 J9 J10 J11 J12 J13 J14 J15 J16

EK11 K1 K2 K3 K4 K5 K6 K7 K8 K9 K10 K11 K12 K13 K14 K15 K16

EC12 L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 L11 L12 L13 L14 L15 L16

EC13 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16

EC14 N1 N2 N3 N4 N5 N6 N7 N8 N9 N10 N11 N12 N13 N14 N15 N16

EC15 O1 O2 O3 O4 O5 O6 O7 O8 O9 O10 O11 O12 O13 O14 O15 O16

EC16 P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 P15 P16

EC17 X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16

we would:

  • connect BLM_SCALAR::J3_1:C0..C7 with the cathodes of EC1+A1..A8, EC2+B1..B8, ... EC8+H1..H8
  • connect BLM_SCALAR::J3_1:G0..G7 with the green anodes of A1..H1, A2..H2, ... A8..H8
  • connect BLM_SCALAR::J4_1:R0..R7 with the red anodes of A1..H1, A2..H2, ... A8..H8
  • connect BLM_SCALAR::J4_1:I0..I7 with the buttons of A1..H1, A2..H2, ... A8..H8
  • connect the green anodes of EC1..EC8 with BLM_SCALAR::J3_5:G0
  • connect the red anodes of EC1..EC8 with BLM_SCALAR::J4_5:R0
  • connect the buttons of EC1..EC8 with BLM_SCALAR::J4_5:I0

Do you see the logic behind this matrix routing, or do you need additional explanations?

Best Regards, Thorsten.

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Ok, I’ve got 4 quadrants done:

A1->H8 and cathodes EC1->EC8 connected to J3_1,J4_1

I1->P8 and cathodes EC9->EC16 connected to J3_2,J4_2

A9->H16 connected to J3_3,J4_3

I9->P16 connected to J3_4,J4_4

Can you please explain the connection of the extra column and row to J3_5,J4_5?

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I am a big fan of the 8x8 version too, because i think it is more versatile. Anyway seems to be a very common way of design when researching other sources like monome, arduino, livid, etc.

Regarding the buttons i dont think there will be a solution pleasing all of the midiboxers. I personally clearly prefer silicone rubber buttons like the monome solution with an "integrated" led. IMO

it´s not clicky, best for playing live and stylish (in terms of design) but i can totally understand the cons (costs, availability, frontpanel not diy-able, etc)

I´d say "first come first serve" and the creator of the first pcb decides what to use...

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see next page..

Edited by phunk

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That´s a mock up of a 16x16blm with the livid buttons. It has 38x38cm.

gallery_4776_55_36677.jpg

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man, those 8x8 sheets look nice and for $130, not to painful on the wallet for the big one..

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has anyone considered a 8X16 grid? Having to page over 8 steps for a 16 step seq sounds a little tedious but having to page up and down doesn't sound too bad..

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Can you please explain the connection of the extra column and row to J3_5,J4_5?

This can be decided layout-driven (there are multiple possibilities) - for extra buttons it's only important that each button/LED combination is individually accessible in the matrix.

(I will check your layout once it's finished)

Best Regards, Thorsten.

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