TK.

MBBLM schematics and PCB discussions

118 posts in this topic

Could be the BC337 transistor replaced with the BC337-16 transistor?

The first one has a HFE/63 and the second one HFE/250.

I'm asking this just because my supplier have only the BC337-16.

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The "-16" doesn't have anything to do with the hFE, it's the maximum voltage rating.

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The "-16" doesn't have anything to do with the hFE, it's the maximum voltage rating.

I tought that had something to do with HFE because the difference showed on the list is only the HFE!

bc337.jpg

Both have 45V and 800mA, changes only this HFE/value.

The datasheet linked from the supplier is the same for both the models:

BC337 Datasheet

What i can understand from the datasheet is that:

The standard "BC337" model have:

HFE1 min.100 and max.630

HFE2 60

The "BC337-16" model have:

HFE1 min.100 and max.250

HFE2 60

At the end the question is if this BC337-16 model can be used with the BLM module, unfortunately i don't have a great knowledge about transistors, so i don't know if the max voltage rating can affect in a some way the BLM Module.

Edited by Rics

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Hello everyone! could 2 pins bicolour led be used?

thnx!

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no, such LEDs are not supported (they would require a different circuit and firmware)

Best Regards, Thorsten.

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I've got a problem with a series of buttons.

Four buttons/leds of I1 from J4_1 aren't working no more, i've eight buttons/leds connected to that line, so four are working and the other four no more.

I've controlled buttons, diodes and leds, they are all ok, connections are also ok.

Where i've to indagate to solve this problem?

I've to check the control board IC's, resistors and transistors?

Thank you for the help!

Edit:

I've checked also the resistors and connections on the MBHP_BLM_SCALAR module, but they're all fine.

Could be the IC1 (74HC165)?

But i don't know how to check if it have I0 input pin broke. In the meantime I could try to swap it with another one that i've as replacement.

PS:

To Thorsten or mods, i don't know if it's off topic my question, if it is OT i'll delete this post and open a new thread.

Edited by Rics

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I don't think that an IC is damaged...

Did you build the BLM on a veroboard?

First check should be to find out if only buttons or only LEDs are not working anymore.

Buttons can be checked with a MIDI-Monitor: do they send MIDI events?

LEDs can be checked with a MIDI keyboard (can also be a virtual one): send MIDI events to enable/disable the LEDs

If LEDs and Buttons are not working, the common line connections (C_x, blue signals in my schematic) are the reason.

You could swap two common lines to check if the connections on the BLM_SCALAR module are the reason, or the wiring on your Button/LED matrix

Best Regards, Thorsten.

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Yep, i've built it on a veroboard.

Today i've re-checked all, and i've also disconneted all the AIN modules from the stm core, i've uploaded to the stm core the software that control only the blm module (deleting the ain and din encoder code) and now seems that's working all ok.

So i think that's something related with the AIN modules and the jitter generated by them.

Of course i clamped to ground unused inputs, but i've also a continue streaming of values on the mios studio midi input monitor.

I'll try now to modify the deadband setting to "127" (5bit), but i was experiencing a continue streaming of data in the midi in (checked with mios studio) already with a deadband setting of "31" (7-bit).

I don't know if 5bit is reliable as solution, but i'll try anyway to see if it's a problem of deadband.

Last test will be a switch from usb to power supply unit to see if it's the usb to cause the jitter.

If also this will not work i'll switch back to a REV.D spare pic core that i have from an old project....altough it could seem a fail that i'm not used to. :sad:

Edited by Rics

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I think that the STM32 based BLM + AIN modules are not a good combination.

The multiplexed LEDs produce a lot of digital noise, and the analog inputs are only working in 0..3.3V range, accordingly the signal noise ratio is worse compared to 0..5V range used in PIC applications.

I'm planning to provide a solution with cheap external 5V based ADCs soon (very soon), this will be interesting for you.

Best Regards, Thorsten.

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Thank you Thorsten, i'll see forward for your solution.

In the meantime i'll do that other tests and i'll update on news.

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Hi

my idea for low budged is this button

http://www.ebay.de/itm/100x-ALPS-SKPM-SMD-Taster-softfeeling-/300694803665?pt=Elektromechanische_Bauelemente&hash=item4602ce94d1

(http://www.alps.com/WebObjects/catalog.woa/E/HTML/Tact/SurfaceMount/SKPM/SKPMAME010.html)

+

2 Part of Acryl ( 3mm in 20x20mm + 1mm in 22x22mm) put together with some acrylic glue - so that the cap cant fall out of the hole(<<--not my idea :) )

The button is very small - 6x6 mm and with 6,5 cent very cheap.

Cost would be arround 30-40 € inkl. the acryl caps .

Edited by Zossen

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I have tried these buttons (though I'm not sure they're the same force). The ones I tried were nice feeling, quiet, but a little too much force required to push for my taste.

A word of caution with your acrylic button caps. I have tried laser cut acrylic caps (with Alps SKPG buttons) and have found it quite difficult to get them to work well. The gluing is very tricky and time consuming, and the caps often do not track straight or get stuck on the front panel. You will probably find you need to glue the cap to the button actuator. Try a small cheap prototype first! :)

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Hi findbuddha,

thx for your testresults.

There are a few diffent types of the button, but the ebayseller does not tell what typ it is.

When you have fixed the cap to the button, has it worked comfortable ?

Do have some pics ?

but i will give it a try (have some space left on the Acryl) with a few different sizes and shapes of caps

and report the results here.

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Hi, I've attached a pic, sorry about quality (from phone).

The caps are 4.5mm, front panel is 3mm, button actuator is pretty much flush with base of front panel - so they stick out a nice amount. Many of them feel quite good. Some have suffered from excess glue which is blocking the motion - they are quite stiff but still successfully activate. The cap rubbing on the panel makes it noisier than the bare button, but I still prefer this to clicky buttons.

I'm also not sure how long the glue will last.

post-6793-0-07706400-1336637861_thumb.jp

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THX for the pic. :)

i will try a 3 layer design with clear "Bump on" Buttons like this one

http://www.ebay.de/itm/Bump-On-selbstkleb-Scheibenknopfe-13-x-H-3-5mm-20St-/320624577340

(have asked the reseller how much of this buttons he has and he told me he has 900 left)

here is a picture how it works

I hope it works. And when the 0,5 mm acryl is transparent the button is illuminated by the Led.

post-5641-0-82034100-1336655321_thumb.jp

Edited by Zossen

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Hi!

 

for info:

-------

i don't know if you are familiar with aliexpress but it's worst put it in the balance with ebay searches:

it's really similar to ebay bulk orders from china, but with sometimes really better prices,

and rapid delivery options (the 5-7 EMS or 3-7 days DHL are not too expensive if you make a big order)

 

i experienced it to buy 100m of strip led and a dmx led controller,

that was much cheaper than ebay, and delivered in 4 days ! incredible...

 

ie: for momentary tactile switch 

http://www.aliexpress.com/wholesale/wholesale-tactile.html?SearchText=tactile&CatId=0&SortType=price_asc&filterCat=410605,410699,4099&groupsort=1

 

ie2: dual color led / segment indicator

http://www.aliexpress.com/wholesale/wholesale-led-dual-color.html?SearchText=led%2Bdual%2Bcolor&CatId=400101&initiativeId=AS_20130313074102&SortType=price_asc

 

-------

 

I'm planning to make a prototype of BLM16x16,

but the livid-like solutions are too expensive IMO

(rubber stuff + square cut in a frontpanel ...)

 

Standard round tactile switch + led and round cap would be a solution,

but i can't find illuminated tactile switch with a dual-color led integrated...

 

The best solution for a cheap and compact version seems to be 

the technic of the led-over-the-switch (the led act as the caps for the switch)

-> easy panel making (only round holes)

-> compact layout

-> cheap (no caps, no FPE order)

 

i saw this technic for the 16x4 BLM, but i can't find the post again.

 

what do you think of this solution ? 

 

thanks for your advices !

 

Best regards,

 

Thomas

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Such a shame this project caught so much dust! I was going to get findbhuddas PCB etched when I found out it'll cost me some 700$...I didn't really plan to design a new PCB but after I copied the schematic, motivation struck. I can see now how a vero board is actually a faster approach  :rofl:

 

Here's a render of what I have so far. These are 10 PCBs connected together (for the sake of ordering them in an affordable manner). The bottom row needs some work still and the schematics and routing of the 16x4 boards need to be checked. I hope the Eagle file isn't corrupted or anything, since it's just an export from Target 3001.

I'd be very grateful if someone could have a look at that schematic, just to make sure.

 

0.27uutt.jpg

 

Here's the schematic if anyone can be bothered.

 

http://www.file-upload.net/download-7826803/BLM-16x4.zip.html

Edited by diwib

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Here's an exploded view. You can find a lot more details in the MI forums  :smile:

 

6dbe9652b226ee6c78837d7cf3e435.jpg

Edited by diwib

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Good job, but I don't think that there are enough mount holes. These things are pretty long, covered in components and one would be applying pressure over the whole surface. Too much flex in my opinion.

 

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I already had those kinda concerns but those boards might seem longer than they actually are. About the length of a Midialf board which I have right in front of me - if i put it on the edge of my table and hold the other end with my hand and then put a lota pressure on it, it barely bends at all. In addition to that, those pin headers are actually on the backside of the board and the Scalar modules plug right into it, eventually serving as a spacers themselves. If that doesn't work out on my test boards, I can still order 2mm boards, rather than 1,6mm for no additional cost.

 

Here's my stuff plus findbhuddas Scalar board btw. Made in Target, exported to Eagle, I hope without errors. I'm ordering these soon, but I don't think it will be before September that I can test them. And I'm not sure at all if I found all errors yet. I got a feeling there's a very grave error somewhere  :pinch:

Edited by diwib

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Maybe run the Eagle DRC? There are two vias which overlap and many traces below the minimum clearance. Best of luck!

 

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Thanks for pointing this out - good idea using the the Eagle DRC! Most errors didn't exist in previous versions before I moved the pin headers together, since that spawned many more vias :/ And apparently Target is a lot more liberal ^.^

 

Fixed the DRC Errors in the 16x4 board and the Extra 2 board. Used the OSHPark and Seeed Studio DRU btw. The schematics still need to be checked. Once I'm really, really bored maybe...won't be able to order these any earlier than end of this month anyhow.

 

The traces are all fine if you go after OSHParks rules or the Seeed Studio ones. But a lota vias weren't. Oh and ignore the overlaps on the Extra 2 board, those are intentional. More or less.

BLM 16x4 rev 1.0.zip

BLM Extra 2 rev 0.8.zip

Edited by diwib

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I am not sure it is a good idea to do DRC before you know exactly that your schematics are correct...

Edited by ilmenator

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