OPERA ROTAS, a DIY mutant drum machine BUILD THREAD

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SphericalSound
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Re: OPERA ROTAS, a DIY mutant drum machine

Post by SphericalSound » Tue Aug 11, 2020 4:27 pm

Bodo1967 wrote:
Tue Aug 11, 2020 12:48 pm
SphericalSound wrote:
Tue Aug 11, 2020 10:21 am
What FW mean?
Firmware? 8-)

And I ordered one of these ST-Link V2 thingies today, it was about € 3.60 in total. I'll be ready for updates when they come.
And I hope I get the few remaining parts by the end of this week so hopefully I can finish the build soon. Most of it is done now.

The breakout boards are still missing and on their way, so is the 4N35. It only needs to be inserted into the socket when it arrives, and I need to solder the display and the otherwise finished OPL2 sub board. LEDs, pots, switch buttons and the other parts are all done now.
The 4n35 is for midi, as long as is not implemented yet you can use it without it. It needs the screen to boot, tho :tu:

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Wed Aug 12, 2020 1:25 am

SphericalSound wrote:
Tue Aug 11, 2020 4:27 pm
The 4n35 is for midi, as long as is not implemented yet you can use it without it.
Sure, I was aware of that (opto couplers are common in MIDI transmittal after all :D).
SphericalSound wrote:
Tue Aug 11, 2020 4:27 pm
It needs the screen to boot, tho :tu:
The screen has already been lying at home for a week or so, and I do have hex spacers, so this will in any case be done shortly.
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by yan6 » Thu Aug 13, 2020 8:03 am

What are the two blue pcbs at the top of the main board, are they part of the kit or a separate purchase

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Thu Aug 13, 2020 8:18 am

yan6 wrote:
Thu Aug 13, 2020 8:03 am
What are the two blue pcbs at the top of the main board, are they part of the kit or a separate purchase
Those are the 4067 breakout boards. They are not included with the kit (at least not with the 'basic' kit I bought), but they aren't expensive.
I paid less than 3 Euros for two of them.
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by yan6 » Thu Aug 13, 2020 8:19 am

Sorry to be dumb, but is there a purchase link for them

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Thu Aug 13, 2020 8:22 am

yan6 wrote:
Thu Aug 13, 2020 8:19 am
Sorry to be dumb, but is there a purchase link for them
I simply bought mine off Ebay. According to the tracking code they passed German customs by now so I hope to get them before the weekend.
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by yan6 » Thu Aug 13, 2020 6:40 pm

Thank you !!

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Fri Aug 14, 2020 1:39 am

Bodo1967 wrote:
Thu Aug 13, 2020 8:22 am
I hope to get them before the weekend.
Bingo. Received them yesterday, as well as the opto couplers :D.
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by rosch » Fri Aug 21, 2020 6:25 am

Cool, got the last one from Etsy :hihi:

Looking forward to doing this

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by cafesinleche » Fri Aug 21, 2020 12:50 pm

super interesting! is there a way to sync with external gear?

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SphericalSound
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Re: OPERA ROTAS, a DIY mutant drum machine

Post by SphericalSound » Sat Aug 22, 2020 4:44 am

cafesinleche wrote:
Fri Aug 21, 2020 12:50 pm
super interesting! is there a way to sync with external gear?
Yeah, currently it does clock out pulses to synch. There are midi in hardware implemented too. The firmware is not written yet. Should be ready if there are no incidents this fall. Hopefully!

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Sat Aug 22, 2020 5:40 am

SphericalSound wrote:
Sat Aug 22, 2020 4:44 am
There are midi in hardware implemented too. The firmware is not written yet. Should be ready if there are no incidents this fall. Hopefully!
That would indeed be great :tu: . That would make it so much easier for jamming - and possibly also for track-by-track recording: Sometimes, "120 bpm" vary a bit, depending on clock sources (as I wrote earlier in this thread, I am using the E-RM MIDIClock). I know of somebody who had prepared a track in 140 bpm - when transferring it into Cubase it turned out after some experimenting that he had to change the rate to, and I quote :!:, 139.936 bpm to get everything tight 8-) .

In any case, I have already ordered the ST-Link v2 programmer. When you're done with the firmware, please also provide idiot proof ;) instructions on how to get the firmware into the Opera Rotas 8-) .

And btw, mine is ready for testing now. I made a wooden base plate to mlunt it to as well, and I'm considering an acrylic cover plate or such at least for the upper part.
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by rosch » Sat Aug 22, 2020 7:01 am

Perhaps a dumb question: The bluepill, is that the MCU that comes with the board?
if not, would this be the right one? (image=ebay link)

Image

thanks

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Sat Aug 22, 2020 7:59 am

rosch wrote:
Sat Aug 22, 2020 7:01 am
The bluepill, is that the MCU that comes with the board?
Yes.
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by rosch » Sat Aug 22, 2020 8:37 am

thanks

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Sat Aug 22, 2020 9:20 am

Bodo1967 wrote:
Sat Aug 22, 2020 5:40 am
And btw, mine is ready for testing now.
Just switched it on for the first time.

Wow. Already lovin' this little machine :mrgreen: :tu: :nana:.
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bjarne » Sat Aug 22, 2020 1:38 pm

I haven’t built mine yet, but I look forward to having access to the firmware for tinkering.

A question on the low profile buttons: i guess it would be wise to replace these with some taller if making an enclosure? Not sure how to go ahead with this though since some components (eg capacitor and jumpers on stm32) are quite tall.

Anyway, it seems quite sweet even without an enclosure.

Cheers
SphericalSound wrote:
Sat Aug 22, 2020 4:44 am
The firmware is not written yet. Should be ready if there are no incidents this fall. Hopefully!

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by misa » Mon Aug 24, 2020 2:58 pm

I have a stupid question:

what's the orientation of C1? Negative "up" (towards the Blue pill)? That's what it looks like in the videos, but it's very blurry. the indicator isn't so clear to me.

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Tue Aug 25, 2020 4:26 am

misa wrote:
Mon Aug 24, 2020 2:58 pm
what's the orientation of C1? Negative "up" (towards the Blue pill)? That's what it looks like in the videos, but it's very blurry. the indicator isn't so clear to me.
Yes.
or1.png
(copyright disclaimer: this is a detail from one of the original pics on Tindie, I only added the green and red arrows and polarity indicators).

Basically, the non-filled area with the square solder pad is always the "+" side with electrolytic caps. The "-" side has a round solder pad and is often filled in on the silkscreen (usually white).
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... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by rosch » Tue Aug 25, 2020 8:17 am

A question about the OLED.... I just got a 0.96" one but with the same number there were also larger ones. Does it matter which size i get?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by misa » Wed Aug 26, 2020 5:20 pm

Bodo1967 wrote:
Tue Aug 25, 2020 4:26 am
misa wrote:
Mon Aug 24, 2020 2:58 pm
what's the orientation of C1? Negative "up" (towards the Blue pill)? That's what it looks like in the videos, but it's very blurry. the indicator isn't so clear to me.
Yes.

or1.png
(copyright disclaimer: this is a detail from one of the original pics on Tindie, I only added the green and red arrows and polarity indicators).

Basically, the non-filled area with the square solder pad is always the "+" side with electrolytic caps. The "-" side has a round solder pad and is often filled in on the silkscreen (usually white).

Thank you Bodo!

kainiggemann.bandcamp.com
anterasa.bandcamp.com
gratofficial.bandcamp.com
thedorf.net

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by SphericalSound » Wed Aug 26, 2020 8:28 pm

rosch wrote:
Tue Aug 25, 2020 8:17 am
A question about the OLED.... I just got a 0.96" one but with the same number there were also larger ones. Does it matter which size i get?
As long as it has the same pins configuration and resolution (128x64) should be :tu:

In any case, maybe better use a 1x4pin female socket to change it in case it would not be compatible, but it should 95% work

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by SphericalSound » Wed Aug 26, 2020 8:30 pm

Bodo1967 wrote:
Tue Aug 25, 2020 4:26 am
misa wrote:
Mon Aug 24, 2020 2:58 pm
what's the orientation of C1? Negative "up" (towards the Blue pill)? That's what it looks like in the videos, but it's very blurry. the indicator isn't so clear to me.
Yes.

or1.png
(copyright disclaimer: this is a detail from one of the original pics on Tindie, I only added the green and red arrows and polarity indicators).

Basically, the non-filled area with the square solder pad is always the "+" side with electrolytic caps. The "-" side has a round solder pad and is often filled in on the silkscreen (usually white).
That´s correct. Thank you Bodo1967 :tu:

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by Bodo1967 » Thu Aug 27, 2020 1:31 am

SphericalSound wrote:
Sat Aug 22, 2020 4:44 am
Yeah, currently it does clock out pulses to synch. There are midi in hardware implemented too. The firmware is not written yet. Should be ready if there are no incidents this fall. Hopefully!
My ST-Link v2 thingie arrived this week, so can't wait to make the OR sync to an external clock (DIN sync or MIDI would both be OK).
... why buy it for $100 when you can build it yourself for $150?

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Re: OPERA ROTAS, a DIY mutant drum machine

Post by autodafe » Tue Sep 01, 2020 11:56 am

I finished building mine, after lots of struggle I (apparently) managed to program the Blue PIll

Then I switched the OP on and noticed that the screen was getting really really hot, at one point it became red and something burned, i presume...
I measured -3.3 Volts on the screen VCC/GND and then realized that VCC and GND on my display board were INVERTED !!! :mad:


Image

I cut the headers on the screen and connected a couple of wires in the correct way. now the screen has the correct voltage (+3.3V), but I believe it's fuc*ed...
The unit doesn't seem to work. No noise from it, no leds light up, buttons do nothng as well as pots...
I guess that something shoule light up even if the screen is gone...

Any idea on what to troubleshoot next? maybe something else got fried by inverting the polarity of the screen ??

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