MB-MTRX (8x8 LED Matrix) Bulk Order

[m00dawg]

I have been working on an 8x8 LED Matrix board for my own MB-SID synth and figured I would offer it up for a bulk order in case anyone was interested in having a printed version cheaper than having one-off done via BatchPCB or somewhere else.

Information about the board itself can be found here.

The bulk order page can be found here.

Adding yourself to the bulk order page only indicates intent but isn't a full obligation at this point. Please only add yourself to the list if you are serious though!

Prices should be about $15 (not including shipping) for 25 boards or about $8 for 50 from Advanced Circuits. 25 is the minimum I am willing to do since, otherwise, folks can just have their own boards made via BatchPCB for about the same price.

The design is open - you can grab the Eagle files from one of the above links if you'd rather do it on your own. If you have any suggestions, however, just let me know and I will see if I can implement them if they make sense for the design goals.

EDIT (2011-09-13): Added Pic of board layout

Edited September 13, 2011 by m00dawg

[mastomo]

great !!!!

i'm in :flowers:

my name is on this bulk order list

[m00dawg]

I updated the design a small but by going ahead with the jumper idea. Now it is possible to share JD8 (for control surface designs mirroring the MB-6582) or simply use one of the pins on the jumpers separately, avoiding having to share JD8 with the LEDs. I can't think of a great reason to do it that way unless one was using separate LED and button matrices, but I figured I might as well provide that as an option, just in case.

I haven't regenerated the pricing or anything but I wouldn't imagine it would change much. We have 7 orders now - the price for 15(using the old quote) will be about $25 which is lower than having a one-off done via BatchPCB. So I may lower the minimum to 15 if everyone is ok with that pricing.

Edited September 11, 2011 by m00dawg

[m00dawg]

A friend at my local hardware meetup group recommended this place for doing some orders. They can both compete with BatchPCB for one off (with slightly different requirements) or medium-orders. In doing the match, 20 boards would be about $10/board which isn't bad.

Otherwise it would be about $17 per board so if we can't get to 20 or 25 boards for the bulk order, this may be a feasible option depending on how much folks want to pay since it's still less than BatchPCB.

I think they might be using a purple soldermask as well so that's fun!

It's a smaller shop than BatchPCB and certainly than Advanced Circuits but it's much easier to submit designs and have real feedback so I'm inclined to give these guys a go. I may be getting some smaller boards done sooner than this bulk order may be ready and if I do I'll certainly share my thoughts.

[Altitude]

Talk to Nebula, he uses those west coast guys and yes, its a better deal than BatchPCB. Anything approaching 50 boards, I'd go with advance circuits though

[m00dawg]

The setup fees for BatchPCB irritate me. I'd rather they just roll that into the price because I never end up ordering anything from them because I'm waiting to lump all my boards together. But I don't finish some of those boards without first having boards so it ends up being this vicious cycle :)

Certainly nothing against BatchPCB as I have had boards made from them and they do good work but these guys are good on price, seem friendly, are easy to work with - it's fantastic!

As far as 50 boards, I just don't see hitting 50 for this run but yes at that size, Advanced Circuits starts to become quite economical. They irritated me earlier today though by not giving me the usual customer service treatment I am used to when I have asked them questions in the past. Their responses just seemed hurried and vague...

[ilmenator]

I can only wholeheartedly recommend Laen's excellent PCB service with the purple boards. Even if you can get a similar price tag from Batch PCB if you actually manage to do a group buy (and thus go to larger quantities), I think it is worth supporting a low quantity service like Laen's. Just being able to order small boards in small quantities has helped me out a lot in the past.

[m00dawg]

Good to hear! I'm definitely going to try him out for at least one set of boards I need for my modular passive mixer I've been working on. I actually need multiple copies of the board so the minimum quantity actually works in my favor :)

And for this bulk order it means that, if people don't mind paying a bit more, we can order a small batch (20 at $10 a board or as little as 3 at $15 by my math).

[m00dawg]

So I've been thinking about making things simpler for my own CS design and perhaps moving to a system where I mount shift-registers directly on the control surface modules (including the 8x8 LED matrix). This would do away with the requirement to use a transistor sink (ala MB6582) but also means that folks wanting to use the LED matrix in a standard MB-6582 might be stuck.

Curious what people currently on this bulk order are interested in doing? I could put the SRs on the board itself, or just go to a standard pinout which one could use (with an extra board or clever wiring) on the MB6582 though I personally favor SRs on the board because it means the wiring of all my CS modules will be much simpler (or so it that idea).

Still pondering things so I haven't made up my mind on it yet but wanted to keep folks in the loop! The good news is that the board house I was going to use is still quite inexpensive for folks that might want to use the old design if I do change things around.

[rosch]

so this could be used with TK's standard configuration? or will i need the specific MB6582 firmware?

one could also use low current leds, without transistors, no?

so, i don't care for a few bucks more or less. if you like let's get some made. if it's more expensive and a really small run i'd probably take just one.

[m00dawg]

As far as TKs design, yes and no. For the modifications, there are two ideas I have which affect the usability of the board in different ways (though arguably both are still fairly flexible). The LED wiring will generally remain unchanged because the "standard" MB-SID wiring layout still uses a matrix so this is really only for the behavior of the buttons.

1. Put the shift registers on the board itself such that you only have to connect CORE J8 and J9 to the board. It will have headers to go from the CORE to the additional modules in your control surface. In other words, with this option, there are no DIN/DOUT boards as those have been moved to the various control surface boards.

Pros: No wasted space for DIN/DOUT modules in your enclosure and there can be fewer wires connecting the other parts of your control surface together

Cons: I haven't tried adding shift registers to the matrix board, but it will likely make it at least a little bigger. Firmware modification may be necessary, but only to define which I/O pins go to where so those should be easy.

2. Assume DIN/DOUT boards will be used external to the LED Matrix and provide headers for these solutions.

Pros: Will work with TKs wire outputs and is otherwise very flexible. A jumper could be used to tie the buttons to GND for a standard solution. Otherwise one could use those pins to wire up the buttons in a matrix (with the help of some addition wire off-board - I think).

Cons: Won't work as a drop in to the MB-6582 board after these changes are made and will otherwise require DIN/DOUT modules to be used (or similar)

Still playing around with the idea as a whole so, at the moment, I haven't done anything to the LED matrix board just yet. I have thought about "both" as an idea. So having option 2 but making a board that you connect to it using the same header positions that would then have the shift register stuff for folks that don't want to use separate DIN/DOUT boards. That won't exactly be cheap but is still a very feasible solution, I think, and keeps the LED matrix board itself smaller.

That said, the beauty of the above board shop is that the price includes 3 boards, so costs aren't really too bad if we have as few as 3 people interested. To do medium runs (say 20), costs go down quite a bit at that point. That makes any of these boards designs feasible for what people want to ultimately do.

[m00dawg]

Spent some time thinking about this while working on my other boards. I think the size of the LED matrix board would grow in size too much for me to be happy if I tried to cram shift-registers on it. So, instead, my idea is to convert the current LED board design to one that can accommodate the "standard" wiring by default. For folks (such as myself) wanting to do special things, a daughter-board can be used. In my case, I am going to make a daughter-board to house shift registers, resistors, etc. since the rest of my control surface is likely going to use board-mounted shift-registers.

For folks wanting to use a button matrix (ala MB-6582), another add-on board could be used. That's probably not something I will be designing myself unless folks already on the bulk order would like it (since originally I was thinking of using a button matrix when I designed the board initially).

Everybody wins this way, except for those wanting to do fancy things, as this will increase the costs, but I think is the best route to go to offer the most options.

Thoughts?

[rosch]

works for me!

i'm planning to do the TK standard control surface.

:thumbsup:

[m00dawg]

Ah well in that case you'd be all set :) The only catch for you is I will likely have 1 GND pin for each row of buttons (2 total) you will have to account for. I have to do it this way if I want to offer a potential compatible option with a button matrix. I may try to see if I can make that easier via a jumper or something, though. I'm hoping to start work on this tonight so should hopefully have some layouts to share in a few days.

[m00dawg]

Still need to work on the labeling (pins are swapped for some of the headers, stuff like that), but here is what I'm envisioning it to look like. The board is bigger on all sides, but only by a little and, unlike the old board, is symmetric for the OCD folks :) There are two planes for the buttons that will normally be tied to ground but could be used for a button matrix using a daughter board. The headers are intentionally on the top left to make such a daughterboard smaller (and thus cheaper). Since there is no need for diodes, I removed these off the main board. Folks wanting to do a button matrix could add them onto the daughterboard I think (I don't believe they need to be close to the buttons to work right, although I'm not 100% sure on that).

Once I finish this, I'll make the daughterboard next which will basically be a DIN / DOUT board mounted to the back with the idea, as noted previously, being that the board can be part of a chain when using shift registers mounted on control surface boards directly. Fare warning, there will probably be some SMD work involved here since, so far, I have had to use SMD shift register chips for my other control surface components and would prefer to use all the same chips throughout. Plus it should end up saving space (and thus cost) to have the board made.

[m00dawg]

Here's a better version of the 8x8 Standard LED Matrix and of my SR daughtboard.

I had the wiring backwards for the LED Matrix, which would be probably easy to fix in software but I wanted to stick with a drop in solution for folks trying to go with standard wiring (at least for the LED matrix itself). So that is fixed and I added some nice labels to make it easier to hook it up however you might want.

The SR board is, well, I feel like it could be simpler than it is. Thought about using standard DIP SR's instead to see if it would make things a bit cleaner (fewer vias maybe). I am using SMDs for other boards so I figured it might be better to use SMDs for this one too.

I will likely order both boards soon but I'm moving in a week so I will probably have to wait a few for things to settle down. I'll be using DorkBot so I'll have a few extras of both boards if anyone wants to have whatever I end up not using (if I don't screw up, I'd only use one board of each :) ).

As for the full bulk order, I'll let things float for now but given the interest the best option is to just buy the board from DorkBot and split the costs.