So I should be able just to use the out on the Midi i/o correct? so J11->midi I0-> Quad IIC BLM connector
So I should be able just to use the out on the Midi i/o correct? so J11->midi I0-> Quad IIC BLM connector
Yes, it should work from J11E. Or if you connect a MIDI IO board, you could for instance take MIDI IO4 from J2.
i got a message from FORMULOR:
Ihre Datei enthielt Effektfilter zum abrunden der Ecken.
Diese werden von unserer Maschine als Rechtecke ohne Abrundung interpretiert, da dies nur ein visueller Filter ist und nicht vektorisiert ist.
Für die Produktion haben wir die abgerunden Ecken in Vektoren umgewandelt, um Ihnen ein gutes Ergebnis liefern zu können.
Die Produktionsdatei finden Sie am Ende dieser Nachricht.
I dont get the product up to now, so i cant proove that, i let you know…
Okay, thanks for the file, let’s see how yours goes and I can add it to the OP. I didn’t have issues with mine (corners are properly rounded) and I think TK.s was also good? In any case, the spacer holes are a few mm larger than the buttons.
TK.: very nice! It looks like the slider implementation is very good. I guess you kept the longer sliders in? This will be a personal preference I suppose. An idea I had was to make or buy some silicone covers to use as slider caps. This might make them a bit more ergonomic and also act as diffusers for the LEDs which can be quite bright.
The long slider shafts are ok for me. LEDs are too bright (especially the white ones) with a 220 Ohm resistor, I will probably replace it by a 1k resistor. Silicone covers would be nice.
I take it that there’s no issues with the case? Stability (i.e. no PCB flex) is good with the extra standoffs? Are all M2 grub screws installed? Do the bottom feet work?
Thanks for the reminder about the bottom feet, I forgot to install them and that’s also the reason why the case slipped sometimes during the video recording. Now it’s stable.
Yes, I installed the M2 grub screws, PCB is stable when I push the buttons
Okay, thanks for the file, let’s see how yours goes and I can add it to the OP. I didn’t have issues with mine (corners are properly rounded) and I think TK.s was also good? In any case, the spacer holes are a few mm larger than the buttons.
They are good, but I’ve only 4 spacers, a spacer for each screw would be better to avoid that the PCB is bended during mounting
@Altitude: nice panels 
Best Regards, Thorsten.
The long slider shafts are ok for me. LEDs are too bright (especially the white ones) with a 220 Ohm resistor, I will probably replace it by a 1k resistor. Silicone covers would be nice.
Notice I recommend 10k for the LED resistors, hopefully you can change them. For the covers, perhaps some sort of silicone block or tube could be used, I had a look at the hardware store this week but didn’t find anything. Or unmelted hotmelt glue sticks?
They are good, but I’ve only 4 spacers, a spacer for each screw would be better to avoid that the PCB is bended during mounting
I don’t quite understand; only two circular “washers” should be needed (right-most top and bottom viewing from the PCB front) as the remaining PCB area is covered by the spacer?
i got a message from FORMULOR:
I dont get the product up to now, so i cant proove that, i let you know…
[BLM_spacer_3mm_Formulor.eps](< base_url >/applications/core/interface/file/attachment.php?id=12309)
yes it works:
Thanks, I added it.
Wow. That’s amazing looking! :)
Wow, what an awesome build this all was.
Now that the ‘hard’ part is done, comes with ‘soft’ part: What’s not clear to me, using a virgin PIC (F4620), is what firmware this BLM would use? Is it just a matter of loading the bootloader and that’s it? Or should the blm_scalar_v1.0a.zip file from the MIOS download site?
Congrats on the build if all is well!
You need to first burn a virgin PIC with the MIOS bootloader. After you can send it regular MIDI data using MIOS Studio.
The easiest way is with a normal 8-bit Core because it has standard MIDI ports.
The update is possible if you have your SEQ ready to go with the DIN cable and everything, just configure the router page using e.g. USB2->MIDI3 and MIDI3->USB2. Select USB2 as the MIDI in and out on MIOS Studio and you’re talking to the Core8!
first MIOS bootloader if virgin pic via burner …and after the .hex file via midi in blm_scalar_v1.0a.zip…
for grounding the 4 unused AINs inputs:
take a 10 pin IDC male connector, kill the 5V pin , and solder AINs and grounds pins with a unused component leg, easily removable so it could be evolutive for future…
Yeah Andy! your solution is more simple! i am so stupid that i would have never thought!
A problem… and a solution.
Testing the BLM the last couple of weeks I was getting intermittent behaviour. Notably the SEQ was having trouble communicating at power on and the miniCore would reset if too many blue LEDs were lit. I think what happened is large spikes were causing the supply to drop out, which might appear as a reset pulse on pin 1. The problem remained if I used different 5V PSUs (switching and linear) and adding extra caps to smooth the rail didn’t help. TK. managed to get all of his LEDs lit without any comment, so I can’t rule out that it is particular to my build, or is caused by faster switching due to the Schottky diodes that I added. I’m interested to see how others go with their BLMs.
The power situation is not ideal. Running everything connected to the DIN cable means there’s quite a lot of cable impedance/inductance and the regulation is far away. Using 5V means there is no headroom for a normal regulator, and as the Quad IIC board uses the same rail to drive the MIDI IO circuit, using a higher voltage here isn’t really feasible.
One option is to use the extra case holes to connect a higher (e.g. 9V) DC input, then regulate down from there. A simple regulator could be built in the “muck” area present at the top (but beware that the acrylic spacer sits over the other side of the PCB).
Or, continue to use the 5V line from the Quad IIC board but with a regulator injected in. 5V input means you need a “Buck Boost” converter. I bought an adafruit “Verter” board, which are around $10. I thought the simplest place to put it would be in place of the R1 bridge wire, but the problem is really on the miniCore side. So I cut the 5V and ground lines coming in after the DIN socket. For mounting I used an SIL header in the blank muck area; there are some unused functions on the Verter PCB like enable etc. I only had one terminal socket handy so I soldered directly to the output.
The result is much better: the BLM initialises as soon as the SEQ is ready and there is no problem illuminating all LEDs. The Verter specifies that its normal 5V output is actually 5.2V, which is still fine for the PIC and its analogue inputs. This also helps with the inevitable voltage drop observed when many LEDs are lit.
Happy BLMing!
Someone asked about power draw (also added to the first post):
- Using the Verter, standby voltage and current is 5.2V and about 30-60mA.
- With all LEDs lit (both colours) the draw goes up to 647mA, although this would never be done in normal operation.
- In track mode with all 16x16 blue LEDs lit the draw is 467mA and the voltage drops to 4.72V. I don’t really perceive a difference in brightness, but it could only be a good thing! As long as the ADC inputs are scanned relative to the supply voltage you shouldn’t lose control at the top end.
Testing the BLM the last couple of weeks I was getting intermittent behaviour. Notably the SEQ was having trouble communicating at power on and the miniCore would reset if too many blue LEDs were lit.
While reading your posting an idea came into my mind: the PIC device configuration (which comes with the MIOS bootloader) is preconfigured with a brown-out reset detection at 4.5V, which means if the supply voltage falls below this limit, the PIC will be reset, although it also works at lower ranges.
I selected this high BORV setting to ensure, that for example an ongoing IIC EEPROM programming operation will be interrupted (by resetting the PIC) before the external device is outside the valid voltage range during power-off - this could lead to data corruption.
But the BLM16x16+X doesn’t access external EEPROMs, so actually the BORV could be lowered to 2.89V or even 2.14V
Unfortunately this can only be done with a PIC programmer.
Best Regards, Thorsten.
I’m almost done populating the board after working a few hours each week on this project. As others have noted, this is a pretty tedious build. I worked out a method that sped up the diode installation process for me. Take a small piece of veroboard and make a little template for the diodes. You can quickly place a diode on the small board and then flip it over to trim the leads. After removing the trimmed diode from the board, trim an extra millimeter from each lead so that once the diode is placed on the pcb the leads won’t protrude from the front side. I made small piles of trimmed diodes and soldered one row of diodes at a time. The diodes were easy to place on the pcb because they were already properly formed, and I never had to flip the large pcb during this process.
