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The Flatsequencer (MBSEQ V4 with TPD, battery powered)


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End of year holidays = build time ;-)

Here is a new specialized "form factor" for a MBSEQ, that is based on Wilbas CS PCB and the new STM32F4 board.
Of course, it involves a bit of DIY to achieve the flatness, some connections have to be soldered without IDC connectors, and U-shaped aluminum rails have to be cut, but no problem! :-)


Tech specs:

* "Slim and wide" MBSEQ V4, only 21mm high, about 70 cm wide

* 40x2 OLEDs for high screen update speed and low power consumption

* Pushable encoders for accelerated scrolling/note input

* Battery powered for high mobility and no necessity to carry around a PSU for a jam session with friends

* High quality omron tactile switches for a few million cycles (at least that is what they are advertised for)

* Green transparent acrylics base and side panels for ambient light gathering and green beam emission :-)

* Additional bling and functionality achieved with the TPD board :-)

* Laser engraved Manga, that has been "inked" for a higher contrast :-).


More pictures will be added, as the build progresses, but so far things are looking good!

The battery is a 6 cell 2700mAh AA NiMh soldered pack, that can be recharged with a simple wall charger (the charge port is installed in the upper aluminum rail). A small integrated high-efficiency switching PSU converts the 6 - 9V from the battery pack down to a stable 5V. USB powered operation is optional and switchable. The battery actually lasts for many hours, i have not managed to drain it during the assembly test time, I guess it should be good for at least an evening of jamming, but maybe even 10 hours (current not measured, yet). Using NiMH and not LiPo batteries was a requirement, due to easiness of charging and battery safety.

This unit was especially built for use on a MIDIfied piano. It fits perfectly on the central noteholder and after attaching just 2 midi cables, one is ready to jam :-). The amount of MIDI ports has been reduced to 4, as more is not necessary for that usecase, but an additinal four MIDI ports can be stacked on top (right side of the unit, see a picture, that is posted later on ;-)).

If you are interested in the Formulor/Ponoko plans or have general build questions, say a word, and I will make them available publicly and give advice on how to build it.

Hopefully, you are enjoying the report and maybe get some ideas for building a non-standard SEQ? :-) It is the best hardware sequencer on this planet and deserves some customization efforts to create a unique, personalized unit! :-)

Many greets,




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Thanks, guys.... more pictures soon, as the build progresses! :-)

Andy: there are button caps, these are just not standard and require a bit of labor to fit on the omron switches, but they have a perfect feeling! :-)

Many greets and thanks for your comments!




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Thanks, TK! :-)

Here are two more views:

a) the unit charging, using an old retro 1980s NiCd charger

b) and when turned on in battery mode

The MIDI ports are actually a bit taller than the case, but that is not a problem...

Still some parts are missing, but it is working alright :-)

Many greets,





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Thx :)

Sauraen: the OLEDs (picture one) are the same Raystars as in Jbdivers thread:

Great price on tme.eu, but should also be available on mouser. The displays look great and are highly recommended! :-)

EsotericLabs: The exact dimensions of the case are 70cm x 15cm x 2.1cm, using cheap aluminum "U" profiles, with dimensions 10mm x 15mm (vertical side) x 10mm. Then there is a big acrylics baseplate and three acrylics top plates. Actually, I think that I bought the black center part from you last year, thx again! :-).

The core is placed below the manga, it had to be soldered quite flat, with only 15mm of vertical space to work with :-).

It may be a bit tight in there, but all fits, see picture two. There are switches for battery or usb power, a small switching regulator (inexpensive ubec from the rc hobby sector), a charge port and a cutout in the aluminum top profile for easy access to the sd card and the micro usb port. The battery is just a quickly soldered-together NiMh AA pack, 6 cells for now, but i found some available unused space above the tpd, might add two additional cells for more runtime later on. It can be charged with any NiCd/NiMh charger without risk of fire or other problems :-).

Now, fitting the tactile switch caps. It will take some time, as each of them has to be modified a bit to fit, but sometimes easy, repetitive work is just what is needed to calm down ;-).

Many greets,






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Thx, y'all :-)! Good news: because it is nearly completed, I will stop spamming this forum thread, soon :-).

EsotericLabs: cool! Make sure, you post some pics, if you follow that path! :-) An advantage of this method is, that you need not buy a case. A disadvantage is, that you have to work on the aluminum rails, but it is not difficult - and they are available in a lot of sizes (also higher than 15mm) for cheap.

Shuriken: ah, the build list needs to be processed from top to bottom... the Anushri (thx for that again!) is probably due somewhen in 2017, given the little one does not interfere so much ;-).


Here is a picture of the bottom panel of the unit. Most module interconnections are "spaghetti wired", as there was no room for proper connectors. But these wires are well protected behind the acrylics bottom cover. The top acrylics panels and the bottom panel are held together by > 2x50 screws and center hex spacers. In conjunction with the alu rails, this box is really stable, but one should invest in an ergonomic screwdriver ;-).

Many greets,




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Hi, I'm in the process of sourcing parts for building two MBSEQs myself and was wondering if you can tell me what kind of encoders you used. I would like to go with the pushable encoders in my builds as well. Do you have used them in previous builds already?

Thanks a lot!

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@TK: hehehe! Good idea! Especially the inflatable bit might boost inspiration! ;-)

@EsotericLabs: cool, please do that! If you happen to find any 15mm x 10mm x 10mm *black* U-shaped aluminum profiles, please tell me :)

@westlicht: yes, i used the same old 12mm pushable Alps encoders as used in previous projects, but while these encoders are the next best thing after sliced bread, certain precautions must be met: a) their pins need to be bent to fit in the 16mm encoder sockets. b) the center and the right pin need to be swapped (crossed with a wire). If you are happy to do that, check the photo tutorial :-). Parts number: Alps STEC12E08, you might get these cheap on ebay.

Now, the build is finally complete, and the piano has a worthy and portable sequencer, that also got the gurls blessing. I added 2 more batteries, to enhance the runtime and boost the input voltage to the switching voltage regulator. And I might swap the silver aluminum profiles for black ones, if I can source them. And eliminate a few LEDs on the STM32F4 board, as they shine through the manga. But this is all of secondary priority, it works and I have to thank TK. and Wilba again for their great work!

Many greets,





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@Hawkeye this company offers alu profiles in nearly any color. Sizes are a bit different but  they have something useful *black* for you. I see they also make custom sizes... If you'd need help with the language, let me know.


Edited by EsotericLabs
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