Hawkeye

You should use the midi through on an expander to connect (chain) the other expanders. This way will work for any MIDIbox or any other controller, that you can buy. This will work with a MIDIbox, that has internal merging capabilities - I don´t know, if the MIDIbox64 variants can do that, but as far as I know TK., I would nearly bet on it ;-). You can use 360° endless encoders, which are "stateless" for sending continuous midi events, e.g. controlling the filter on an expander. These digital encoders are connected like "buttons", but use two ports (use DIN modules for them, not AIN which you need for analog faders and encoders). You can use buttons to send preprogrammed MIDI CCs (again, I don´t know, if this is supported by the MIDIbox64) to your expanders, e.g. for patch changes. Have fun! Greets, Peter

Hi Arnaldo, welcome :) 1) Your Roland RD-300SX looks like a very decent keyboard, you probably don´t want to drill it open to add encoders and faders? I´d recommend to build an external MIDIbox controller in a separate enclosure therefore - see answer 3) 2) No, USB-only expanders cannot be directly controlled by a MIDIbox, they need to have a standard MIDI IN port - or you´d need to buy some converters. Also, by using a MIDI through cable, you can control more than one expander from your Roland keyboard without a MIDIbox. 3) Your options are listed on this site: www.ucapps.de - have a look at MIDIbox64 and MIDIbox64E Bear in mind, that MIDIboxes are very modular, you can add any kind of tactile switch (button), potentiometer/fader or rotary encoder with the right modules. By using a "MIDI Merger" (also a MIDIbox project), you can "mix together" the MIDI outputs of your keyboard and your new MIDIbox, to play your expanders (with your keyboard) and control them (with your MIDIbox). Greets, Peter

Hi Ilmenator, sorry for the missing information - the solder pads are 8mm apart on the left, respective right side of each switch. Vertically, they are centered: ---- _| |_ | | ---- You can see them in the photo of the first posting of this thread (slightly blurred, but still visible). I cannot provide you yet with a manufacturer link, because I´ve obtained them very cheap on ebay, but would be looking for another supplier before routing, so the PCB can be reused by other interested users. As far as I´ve seen on the Alps webpage, these kinds of SMD switches are fairly common (5x5mm integrated button, ca 8x8mm case, soft feeling). Nevermind the clean PCB top side :-) I also have the strong feeling, that using a larger BLM matrix (e.g. 2 + 2 shift registers for a 16x16 matrix) increases the routing difficulties :-). Greets, Peter

Hi, you could always let Schaeffer only manufacture the CNC drilled frontpanels and build a modular enclosure from wood, for example. Also, depending on what you really need, you can save some money in Frontpanel Designer, e.g. by concatenating artwork or text into one single HPGL outline object (if I remember that right). Greets, Peter

Hi, on the first page of this thread, you find an overview picture montage of the planned unit in correct relative sizes... it is 600x800 pixels big and every pixel corresponds to 0.3mm giving a total PCB area of 180x240mm. If you scale the picture in your browser to 18x24cm, every component should be correct size :-). The switches have a pin-to-pin spacing of ca 7.5mm, the switch grid should be 10x10mm. The LEDs are 3.2mm x 1.6mm. Still missing in the illustration is one SMD diode per switch, which should be smaller than the LEDs. I am planning for partial SMD coverage of the backside for the MBHP_BLM_SCALAR components and want to route the backside tracks to the frontside with vias to connect all switches and LEDs. It is a next-to-impossible first project for learning PCB routing, typical :-) Greets, Peter

Hi Ilmenator, as far as I can see, it would be one LPC core per large BLM module of 17x17 buttons/duo color LEDs. If there is a solution to drive more than one large BLM with a LPC core, I would be fully convinced to go "modular", because the design goal for this project is minimum build cost. But I doubt, that it is easily possible, because one large BLM already uses 5x3 (=15) 74HC595 shift registers (5 MBHP_BLM_SCALAR modules) and as far as I know, the limit is 16 (or 4xDOUTx4). Of course, one could try to increase the matrix by not using two shift registers for 8x8, but by using four shift registers for 16x16... I don´t know if it would be possible, also regarding LED current requirements (for an 8-LED-matrix, there are BC337 transistors employed, I have no idea, if they would be sufficient for a 16-LED-matrix). Currently, I also have some concerns of how to fit all the necessary traces on a two-layer board with this really dense button/led packing :-). Greets, Peter

yes, totally.

The MB64E supports LED rings, for example (Core8 platform). Also, you can create LED rings using the Core32 platform - tutorial #9.

The Rock impro sounds great! Well done! Greets, Peter

Wicked tune, my friend. Please don´t do drugs! :-) Greets, Peter

Hi, maybe you overheated them during the soldering stage?

That sounds great - I will try to learn Eagle and read a book on PCB layouting with it in the holidays, so it will take some more time for me :-). Greets! Peter

Heheh, exactly what I thought - it has written "Transformers" all over - but it is a really nice color combination, well done!

Hi, dunno about the LCs capabilities, but you can always build a separate MIDIbox offering the additional controls you need and merge the outputs using a MIDIbox merger...

+1 on the protection thoughts... hopefully at some time someone here will come up with a PCB using standard parts, linear supply for the audio components, offering protection and a good build tutorial...

dreamer, they do look nice and while they may seem expensive, they are not really, as jojjelito noted correctly, ´cause if you calculate time for building your own and sourcing the parts, they are quite cheap. I´ve also seen, that Conrad sells some "lineare Netzteile" for those from germany...

Well yeah, I totally second your wishes for easy tools, 10k is way over the top - the eagle autorouter module had to go, too - and budget-wise i´d liked the Eagle standard version better, but it will allow only for euroboard-size PCBs... Will give it a try, when there is some time :)

Just a suggestion, with all that modding around, it might really be easier to sell the MPD24 unmodded and build a new MIDIbox from scratch. Greets, Peter

It will ´prolly be Eagle Pro - i´ve seen all those magazine ads over the last 15+ years, so why not - it is another welcome area to learn something, and I still have a little bit of software budget in the company for this year :-) Edit: wow, really fancy image link :-)

dreamer, those are all switchers :) brrzzztrzts (<- simulation of very high frequency output on the audio lines. probably too high frequency to hear, though :-)).

Bilderbuchi, no problem at all - thanks for your comments - they are appreciated - I have to start learning pcb creation first anyways, so it will take some time before reconsidering modularity vs integration :-).

@Dreamer: Cool - but someone else must do this - I didn´t post explicit instructions in the build tutorial, because I didn´t want to take the risk of bad karma, when someone rebuilds this, forgets that it is plugged in and has a hell of an electrifying trip :-). And also, there are many good (probably better) designs out there, some surely being more efficient (e.g. not pumping 9v * 1.4 into a 5V vreg) or having even better ic-controlled over-voltage protection circuits.

Heheh, now i understand, why i got all kinds of strange motorcycle spare part offers while trying to obtain it on ebay :-)

@jojjelito: yes, 2-color "only" is fully intentional, because of the design goal of minimum price per BLM - but it will be fully sufficient for pattern programming. @bilderbuchi: yes, the cheapest tactile switches with integrated LED illumination, that I found were around 1 US$, so I thought, that 5+9 cents per switch/led are very sensible cost-wise. Also, as the button cap push area is only 5x5mm, it makes sense to have the LED above the area you pushed, for visual confirmation, that you really enabled the step (otherwise only your finger is illuminated :-)). Regarding the integration of the Core... The LPC itself is carried as a "removable" shield on the backside - as there needs to be lots of PCB routing done anyways, it makes sense to integrate it for this module. It is already very specific, anyways. I just measured the space above my Moog LP - and four of these units (18 + 16 + 16 +16 cm) would fit perfectly for a compact 64x16 BLM ;-). So I guess, I have to bribe someone to help with the PCB routing :-) Greets, Peter

Thanks, findbuddha, I will wait for your tests - great work on your BLM, hope everything works! Me just had an idea, how the above design can be improved - consider the shown PCB as the frontpanel of the unit, all switches and LEDs are quite flat and SMD-soldered to it, no real need for plexiglass (but you could have something cut by ponoko, probably). But then, the LPCXpresso and all ports would be exposed, which would not be very nice visually... So, consider just flipping the upper section of the image to the backside. You would therefore only see the solder points for the LPCXpresso, the solder points for the MIDI, USB, ethernet and power sockets and the vias. The BLM_Scalar modules would then be realized with smd components on the backside, just like TKs original design - and would connect to the switches and LEDs with vias. With this method, another two centimeters of vertical PCB space (18x22cm final size) could be saved - and the original 17x4 (x5) horizontal segmentation could be used. Gotta get back to work, thanks for your comments :) Greets, Peter