VOGONS


Show us your custom Physical mt32-pi Builds

Topic actions

Reply 60 of 72, by Mu0n

User metadata
Rank Member
Rank
Member
fxgogo wrote on 2021-11-10, 15:39:

I have only just started my project. Got the HAT soldered up.
MT32.jpg
This thread has given me some great ideas. Love the thought of it sitting inside my PC and being able to route the audio out from the SB or MT32 to my speakers with a flick of a switch. Think I am going to need to get a display the is larger and is closer to the original MT32.

Looks sharp. If I didn't also own a real physical MT-32, I'd definitely do this for a half-height 5.25 drive in my 486DX2/66.

Did you do a cost analysis when you did your own hat (I assume you hunted your own components), as in, the cost per unit if you did more than 1 unit? I'm torn between going above 1 or just stay frugal.

1Bit Fever Dreams: https://www.youtube.com/channel/UC9YYXWX1SxBhh1YB-feIPPw
DOS Fever Dreams: https://www.youtube.com/channel/UCIUn0Dp6PM8DBTF-5g0nvcw

Reply 61 of 72, by fxgogo

User metadata
Rank Newbie
Rank
Newbie

So I got the board from someone on RMC Retro's Discord. I then pretty much had to buy the components with enough to make at least three of them, but I really wanted to make just one and get it working first and the extra components were insurance if I mucked it up. I should see how much this cost, I have the receipts somewhere, and of course I have a spare pi3 so that reduces the cost somewhat.

Reply 62 of 72, by Thermalwrong

User metadata
Rank Oldbie
Rank
Oldbie
Mu0n wrote on 2021-11-09, 16:30:
Ha, should have reread your post. Your design is my favorite and hits all my needs in size/functionality/aesthetics. Is your pro […]
Show full quote
Thermalwrong wrote on 2021-04-02, 17:47:

The front wouldn't look right with the 3d printing layer lines, and my attempts to print text with the 3d printer didn't work out, so I used my Brother QL700 label printer to print out the matte paper label, and the glossy plastic label. The end result looks pretty fantastic to me, but I'd love it if there was a better way to print the matte front part. I Was thinking maybe a PCB with no traces on it, in a black matte finish. That would be cheap-ish and the silkscreen would work perfectly for the button labels.

Something I'd like to look at next is making a PCB that doesn't sit on top of the CPU so it can cool better, there's room in the case for that. But this one works and I can use it now 😀

Ha, should have reread your post. Your design is my favorite and hits all my needs in size/functionality/aesthetics.
Is your project shared somewhere and if no, would you consider it? I'm definitely down to check some PCB costs that would include the button area, but I could live with just the screen area.
I have to fight down the need to use a 20x4 screen especially since it's supported.....

hehe, I forgot about this entirely after I finished it! Thank you for the reminder.
I need to make the PCB into a design that can go onto a Pi3 and tidy it up a bit, but I can definitely share it. My lack of knowledge on how to take the paper facia into something more reproducible - right now it's a bit hard to cut correctly and doesn't look amazing. Idk how to get a matte black plastic printed that would have white labelling though.

Also, pretty keen to get hold of a Pi Zero 2 and make a board for that, should be simpler since it won't be adding an extra DAC

Reply 63 of 72, by Mu0n

User metadata
Rank Member
Rank
Member

The Pi Zero 2 W doesn't seem to offer enough performance right off the bat though, dunno if you've read this:

https://twitter.com/_d0pefish_/status/1454110 … s1_c10&ref_url=

1Bit Fever Dreams: https://www.youtube.com/channel/UC9YYXWX1SxBhh1YB-feIPPw
DOS Fever Dreams: https://www.youtube.com/channel/UCIUn0Dp6PM8DBTF-5g0nvcw

Reply 64 of 72, by Mu0n

User metadata
Rank Member
Rank
Member

Thermalewrong, any chance to get the fusion 360 files? I think I'd make the front part a bit thinner to accommodate a full sized pcb face plate. I need to adjust for the screen I ordered as well as the rotary encoder I selected.
I ordered most of the parts I needed from aliexpress and now the waiting game begins! (Jan 24th ish). I just installed kicad and can share my plate design once I figure it out. I muddled my way through altium circuitmaker, how hard can this one be!

1Bit Fever Dreams: https://www.youtube.com/channel/UC9YYXWX1SxBhh1YB-feIPPw
DOS Fever Dreams: https://www.youtube.com/channel/UCIUn0Dp6PM8DBTF-5g0nvcw

Reply 65 of 72, by Mu0n

User metadata
Rank Member
Rank
Member

Time to whip up something in Fusion360 myself and then easyEDA or kicad for the plate.
I'm finally settled in my choices for the screen (20x4) and inputs (2 buttons, 1 rotary encoder). This foamcore temporary mess what just to get a feel of how things will be placed, but was designed for when I still had a 16x2 screen.

Can someone easily find 3d printed button covers for these momentary tactile buttons?

If you fine people have any special tips for how to secure things on the 60 degree inclination front plate (relative the the bottom plane) at various distances, I'm all ears..

reia7xH.jpeg

1Bit Fever Dreams: https://www.youtube.com/channel/UC9YYXWX1SxBhh1YB-feIPPw
DOS Fever Dreams: https://www.youtube.com/channel/UCIUn0Dp6PM8DBTF-5g0nvcw

Reply 67 of 72, by tabm0de

User metadata
Rank Member
Rank
Member
Thermalwrong wrote on 2021-04-02, 17:47:
That's a nice clean design, I do recommend that you consider adding buttons though. Otherwise you can't switch from MT-32 to sou […]
Show full quote

That's a nice clean design, I do recommend that you consider adding buttons though. Otherwise you can't switch from MT-32 to soundfont mode, unless maybe you use MT32-pi-control software.

Here's what I've been working on for a few weeks now - my MT32-pi case which is designed to look like a shrunken regular MT32, but with the bigger 20x2 LCD.

IMG_0285.jpg

IT's been designed in Fusion 360, but the DAC and MIDI input PCB are currently just on some PCB stripboard that I knocked together. Digitising the physical objects is time consuming work, especially when a print of the top and bottom parts takes 6 hours each. The DAC's audio jack doesn't fit right for instance, but it's close enough to work.
IMG_0293-2.jpg

2021-04-02 18_23_43-Window.png

The Pi3 is screwed in there to be an MT-32PI forever, but on the underside I can get to the micro SD card to swap it out, and the MicroSD card can't fall into the case (very annoying when that happens).

IMG_0299-2.jpg

The front wouldn't look right with the 3d printing layer lines, and my attempts to print text with the 3d printer didn't work out, so I used my Brother QL700 label printer to print out the matte paper label, and the glossy plastic label. The end result looks pretty fantastic to me, but I'd love it if there was a better way to print the matte front part. I Was thinking maybe a PCB with no traces on it, in a black matte finish. That would be cheap-ish and the silkscreen would work perfectly for the button labels.

Something I'd like to look at next is making a PCB that doesn't sit on top of the CPU so it can cool better, there's room in the case for that. But this one works and I can use it now 😀

Is the 3d model available for download ? 😀

naa, nothing yet...

Reply 68 of 72, by khan_games

User metadata
Rank Newbie
Rank
Newbie

Some great pictures in here. Thanks for posting them.

I'm pretty new to all this, but I have my pi 3b hooked up to my DOS PC's game port currently via a Roland MIDI to USB cable and it's working great. I'm just missing sound effects being mixed in.

I'm trying to do some research to figure out how to pipe in the SFX to be mixed with the MIDI stuff and I'm so new that it's hard to really figure out how to do it. Almost all the hats I see that connect to the pins on the Raspberry Pi seem to have stereo RCA output as well as a headphone output. The only ones I see that seem to have an input are sold out (like the PI-MIDI).

Is there a DAC that I can buy to add to this chain to allow me to connect my Soundblaster as an input? Or if there's a hat available that I'm unaware of please let me know.

Reply 69 of 72, by appiah4

User metadata
Rank l33t++
Rank
l33t++
khan_games wrote on 2022-06-12, 18:08:
Some great pictures in here. Thanks for posting them. […]
Show full quote

Some great pictures in here. Thanks for posting them.

I'm pretty new to all this, but I have my pi 3b hooked up to my DOS PC's game port currently via a Roland MIDI to USB cable and it's working great. I'm just missing sound effects being mixed in.

I'm trying to do some research to figure out how to pipe in the SFX to be mixed with the MIDI stuff and I'm so new that it's hard to really figure out how to do it. Almost all the hats I see that connect to the pins on the Raspberry Pi seem to have stereo RCA output as well as a headphone output. The only ones I see that seem to have an input are sold out (like the PI-MIDI).

Is there a DAC that I can buy to add to this chain to allow me to connect my Soundblaster as an input? Or if there's a hat available that I'm unaware of please let me know.

Doing the mixing on the Pi is probably not a great idea, I would suggest an external mixer device instead.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 70 of 72, by Shreddoc

User metadata
Rank Oldbie
Rank
Oldbie
khan_games wrote on 2022-06-12, 18:08:
Some great pictures in here. Thanks for posting them. […]
Show full quote

Some great pictures in here. Thanks for posting them.

I'm pretty new to all this, but I have my pi 3b hooked up to my DOS PC's game port currently via a Roland MIDI to USB cable and it's working great. I'm just missing sound effects being mixed in.

I'm trying to do some research to figure out how to pipe in the SFX to be mixed with the MIDI stuff and I'm so new that it's hard to really figure out how to do it. Almost all the hats I see that connect to the pins on the Raspberry Pi seem to have stereo RCA output as well as a headphone output. The only ones I see that seem to have an input are sold out (like the PI-MIDI).

Is there a DAC that I can buy to add to this chain to allow me to connect my Soundblaster as an input? Or if there's a hat available that I'm unaware of please let me know.

The detail of what I'm about to suggest depends much upon your particular DOS PC and soundcard (and it's driver software / options).

But one budget method often used is :

* route Pi's sound output back into the Line In port of your DOS PC's soundcard
* configure the soundcard's Mixer software to set the relative levels

The result is that the DOS PC is outputting both Sound Blaster SFX, and your Pi's MIDI music, at levels controllable by you using your soundcard's Mixer software.

As mentioned above, a dedicated external mixer is the 'best' way to do it, but there are other options such as the one I've mentioned here.

Reply 72 of 72, by appiah4

User metadata
Rank l33t++
Rank
l33t++
khan_games wrote on 2022-06-14, 13:49:
Shreddoc wrote on 2022-06-13, 06:17:

But one budget method often used is :

This worked great. Thank you so much!

I also use this method, but it's not ideal because games tend to mess with sound card mixer settings a lot and not all sound cards are equal and most do not have the mixing quality of proper equipment. That said, it's a cheaper option than buying an ADC for the pi.

Retronautics: A digital gallery of my retro computers, hardware and projects.