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RoonMatrix Part 11: RoonMatrix Mini with MiniBoss DAC option

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You can optionally use the RoonMatrix with a MiniBoss DAC expansion.
This is a small but excellent digital analog converter, with very good technical and tonal qualities. Especially for the called price.
As this piggyback has to be mounted on the Raspberry Zero 2W, it no longer fits into the U-profile.
That's why I built my own RoonMatrix Mini version - with its own case for the CPU board and DAC, combined with a smaller LED matrix consisting of 9 modules.
With this variant, the LED matrix is ​​a separate module, which is linked between CPU case and LED matrix case via a magnetic contact connector. Awesome, right?

The control software on the CPU board is already prepared for the mini module, and I/O pins were used from the start to connect the LED matrix and the button board to the CPU board, which are not already occupied by the miniboss DAC so that this can work smoothly.

The Miniboss DAC has a stereo cinch output to connect any amplifier, active boxes, or headphones.

Also cool: The Miniboss DAC is recognized by Roon as a WIFI audio device. This means that music can be output directly from Roon to the DAC of the RoonMatrix, and the Roon Zone and playback can be controlled using the buttons!

 

The MiniBoss DAC occupies the following I/O pins of the Raspberry Zero 2W:  

I/O PIN No. I/O Pin designation
3 SDA1-I2C
5 SCL1-I2C
12 I2S_BCLK
31 GPIO6 / DMUTE
35 I2S_LRCLK
40 I2S_DOUT

 

Used I/O pins of the MiniBoss DAC (highlighted in blue)

 

Overview of the two modules of the RoonMatrix Mini.

 

Case for CPU board with buttons and MiniBoss DAC.

 

The buttons and screwing of the buttonboard with the case cover.

 

Case view from the front with magnetic contact.

 

Case back view with audio cinch connections and USB ports.

 

LED Matrix module of the RoonMatrix Mini - View from the front.

 

LED matrix module of the RoonMatrix Mini - back view with magnetic contact and Velcro fastener for a Bluetooth audio module

 

The distance spacers from the matrix modules are adjusted in length so that the LED front closes exactly with the acrylic glass pane.
This does not need a screw joint of the LED modules to the aluminum U profile. The whole thing is held by the screws with the distance spacers.

LED Matrix module - Modules with screwed distance holders and their assembly in the U-profile (side view).

 

LED matrix module - magnetic contact detailed view.

 

RoonMatrix Mini case before contact with the LED Matrix module.

 

RoonMatrix Mini case with contact to the LED matrix module.

 

The magnetic contact bar was soldered onto a small breadboard and then screwed to the case. The cable is routed through a drilled and filed opening to the I/O port of the Raspberry Zero 2W I/O port.

Additional magnets and magnetic contact bar with cable passing (view aluminum profile inside right).

 

Additional magnets and magnetic contact bars with cable passing (view aluminum profile inside left).

 

Passing of the flat ribbon cable from the magnetic contact bar to the Raspberry Zero 2W case.

 

Here are a few pictures of the assembly of the case:

Case is completely open with the U-profile in the front and cover with button (right).

 

View into the U-profile with magnetic contact board and its screw connection, and the two additional round magnets.

 

U-profile with cable passing through the magnetic contact bar to I/O port.

 

U-profile with screwed front part of the case.

 

Case with U-profile without cover and side parts.

 

Attachment of the button board to the cover of the case.

 

 

And here is a picture of the RoonMatrix Mini in action:

RoonMatrix Mini in action.

 

The components list for the RoonMatrix Mini differs slightly:  

(Note: The links to the individual parts are no Affiliate links, I don't earn anything about it. It should only make it easier for you to search for suitable individual parts, which were used in this project. These are the original sources that I used in this project.)

Case for Allo MiniBoss and Raspberry Pi Zero, Acrylic Black (Max2Play)
U-profile aluminum AlMgSi05, HeightxDepth: 40x25, 2mm thick, Length: 300mm (Amazon, Heck & Sevdic GbR)
Plexiglass acrylic glass tinted gray (7c83) light-permeable 21%, 800x200mm, 5mm thick, shortened to: 300mm x 36mm (Ebay, Gerner plastics)
Aluminum rectangular tube profile, HeightxDepth: 35 x 20, 2 mm thick (50cm long, shortened to 7.5 cm as a mounting base for LED matrix on the Raspi case) (Amazon, Hofmann & Pabst GmbH)
20 pcs M5 x 16 Hexagon flat head screws, stainless steel, black (Amazon, Ruixin O)
20 pcs distance spacers M3 brass, 5+6mm (Sourcing Map, Amazon)
4 pcs of screws M2.5 stainless steel 6 mm (Amazon)
4 pcs M2.5 x 6mm Hexagon countersunk head screw, black (Amazon)
6 pcs M3 x 8mm Hexagon countersunk head screw, black (Amazon)
4 pcs of distance spacers M2.5x6mm+6mm brass (Amazon)
Rubber strip seal, 15 mm wide, 2 mm thick, 1 meter long, black (Sourcing Map, Amazon)
Tesa 4651 Premium fabric tape, width: 6mm, color: black, roll length: 25m (2b adhesive tapes)
2 pcs of Opiol distance spacers M3 (Ø inside: 3.2 mm; Ø outside: 6 mm; length: 18 mm) made of aluminum (Opiol, Amazon)
2 pcs of the hexagon countersunk head screw M3x30mm, black (Sourcing Map, Amazon)
5 pcs Cerioll tactile 4-pin miniature button 6x6mm, 11mm head length (Amazon)
1 piece of Euro Epoxy breadboard 160x100mm (Amazon)
1x 40pol. two-row right-angled PCB male connector bar, 2.54mm grid size (Amazon)
4x Neodyme disc magnet, 15 x 3 mm, with 3.5 mm hole and lowering (Amazon)
Solder (Amazon)
Stranded wire 0.14 qmm, red and black (Amazon)
UHU Superglue (Amazon)
9 pcs LED 8x8 matrix with Max7219 LED controller (4 pcs module bar from AZDelivery or as a single module from Hailege, Amazon)
1x 5-pin magnetic plug connector - Adafruit ADA-21440 (botland.de)

as well as: Allo Miniboss DAC (Amazon, Max2Play)

 

Here is a screenshot of the Audio Device Configuration in Roon:

MiniBoss DAC Audio Device in Roon.

The MiniBoss DAC of the RoonMatrix Mini is automatically recognized as an audio device in Roon (marked red here),

 

 

 

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