====== MT32-Pi, 286 Installation ======

This is part of my [[blog:286_pc|286 PC adventures]], a bit of a //finishing touch//, if you like. I already have a MIDI card for the machine, and was intending on adding a connection to my bank of physical MIDI devices... however I caught wind of the latest state of the [[https://github.com/dwhinham/mt32-pi/|MT32-Pi project]] and considered adding a software emulation of a Roland MT-32 synth //inside the PC itself//...

The aim, //in short//, is to put a virtual one of these:

{{:blog:386:mt32.jpg?400|}}

inside this:

{{blog:p1020532.jpg?500}}

//In more detail:// The emulation of the Roland MT-32 has come on significantly in recent years, with the [[https://github.com/munt/munt|Munt]] project releasing a very accurate software emulation of the device - //good enough// for most purposes.

More recently, a project to run the [[https://github.com/dwhinham/mt32-pi|Munt emulator on a Raspberry Pi]] (on 'bare metal', i.e. no Linux OS to boot), called MT32-pi, has reached a milestone where packaging a working MT-32 emulator on a device that can fit in the palm of your hand is possible.

Lots of people are now building these devices, packaging them in to small instrument cases or similar. However, I really liked the idea of having one or two computers where all of the MIDI functionality was //entirely built-in//, and not reliant on external boxes or power supplies. "//Hmm...//" I thought; "//...that 5.25 drive bay looks like just the place I could fit such a device//".

===== Parts =====

   * Raspberry Pi 3B
   * 20x2 alphanumeric LCD display 
       * Emulates the LCD display of the MT-32, as well as display MT32-Pi configuration options on button press
       * https://www.buydisplay.com/character-lcd-display-module/20x2-character
   * M-Audio Uno USB MIDI interface
       * USB input to the Pi, provides one MIDI __IN__ (to accept input from the PC's MIDI card __OUT__), one MIDI OUT (not needed at present).
       * https://m-audio.com/products/view/uno
   * 5.25" PC disk drive drawer
       * To fit the device inside the PC neatly, you could also fasten it to the back of a 3d-printed 5.25" blanking plate if you had the facilities
       * https://www.amazon.co.uk/IOCrest-SY-ACC65085-5-25-Inch-Computer-Accessories/dp/B01LY3YDLN/ref=sr_1_7?dchild=1&keywords=disk+drive+drawer&qid=1621843403&sr=8-7
   * Rotary encoder 
       * Used to control device volume/navigate menus
       * Any //relatively standard// 5-pin controller should work
   * Two momentary push buttons
       * At least 2 buttons are needed - one to switch between MT-32 and Soundfont mode, and one to select the type of MT-32 or soundfont being used
       * //Not latching//
   * Micro-USB to 4-pin PC 'Molex' power connector
       * To power the Pi from the standard PC disk drive connector
   * Innomaker HiFi DAC 'hat'
       * https://www.inno-maker.com/product/hifi-dac-hat/
   * Stereo phono cable (HiFi DAC end) to MPC-2 CD audio 'in' cable (Soundblaster 16 end)
       * This can be made up with a simple 1x4 dupont plug to go on the sound card end of the phono cable 

{{:blog:386:raspberry_pi_hifi_dac_hat_pcm5122_hifi_dac_audio_card_expansion_board_raspberry_pii_4_3_b_pi_zero_06-450x450.jpg?200|}} {{:blog:386:71kg54rj4ml._ac_sl1500_.jpg?200|}} {{:blog:386:377-03_600x.jpg?200|}} {{:blog:386:uno.jpg?200|}} 

{{:blog:386:91zsu44_34l._ac_sl1500_.jpg?200|}} {{:blog:386:61rop2zmvtl._ac_sl1500_.jpg?200|}} {{:blog:386:connect_black_20x2_character_display_to_i2c_adapter_board_with_dupont_wire.jpg?200|}} {{:blog:386:dsc_0098_f7105b71-2252-43e2-8654-112666eb3fc7_600x.jpg?200|}}

===== Logical Connections =====


===== Progress Images =====

Modifying the enclosure to fit the front panel and controls:

{{:blog:286:img20210530114639.jpg?600|}} 

{{:blog:286:img20210530114648.jpg?400|}} {{:blog:286:img20210530114706.jpg?600|}}

Painting the enclosure in the same shade Plastikote blue as the case:

{{:blog:286:img20210530115410.jpg?600|}}

Blanking card made up to block most of the backlight bleeding around the edge of the LCD panel:

{{:blog:286:img20210530141340.jpg?400|}} {{:blog:286:img20210530141352.jpg?400|}}

Buttons, volume control and tinted plastic fitted to front of enclosure:

{{:blog:286:img20210530141418.jpg?300|}} {{:blog:286:img20210530141512.jpg?300|}} {{:blog:286:img20210530141521.jpg?300|}}

Early mockup of the match to the 286 case:

{{:blog:286:img20210530142303.jpg?400|}} {{:blog:286:img20210530142308.jpg?400|}}

Volume control fitted and testing how well the panel fits into the front bezel:

{{:blog:286:img20210602122630.jpg?300|}} {{:blog:286:img20210602122617.jpg?300|}} {{:blog:286:img20210602122609.jpg?300|}}

{{:blog:286:img20210613120942.jpg?400|}}

Micro USB to Molex power fitted, controls and screen wired up and being tested:

{{:blog:286:img20210613120948.jpg?300|}} {{:blog:286:img20210613121014.jpg?300|}} {{:blog:286:img20210613121018.jpg?300|}}

{{:blog:286:img20210613121020.jpg?300|}} {{:blog:286:img20210613121024.jpg?300|}} {{:blog:286:img20210613121026.jpg?300|}}

===== Problems... =====

**[Update 13/June/2021]** - Unfortunately, it looks like the M-Audio Uno interface that I picked up is a different revision to the one being used on my 386, and it throws errors whenever an MT-32 game loads:

{{:blog:286:img20210613161944.jpg?400|}}

... in addition to the error message the instruments don't get set correctly and notes are missing or stuck during music playback.

**[Update 14/June/2021]** - Bought a Roland UM One mk2 MIDI interface to replace the M-Audio Uno. This is on the MT32-Pi compatability list, so fingers crossed it should solve the problems described above.