RoonMatrix Part 5: Button board and connection to I/O port

Now, as shown in the next pictures, the button board is to install.
The Button-breadboard must be adjusted so that it fits into the U-profile and can be completed with the LED modules.
The holes and their distance to each other must match that of the Raspberry Zero so that the button breadboard can be assembled with the distance holders to the CPU board.
The whole thing looks like this:  

The Button-breadboard stands in the way at the right end of the ribbon cable connector of the LED modules. Therefore, a suitable recess in the breadboard must be filed here:

The buttons still have to be wired. For this I use thin copper wire with insulation. One push-button connection is connected to each other.
The counterpart of the button connection, which connects the contact with the common connection, is connected individually to a ribbon cable.
Since we have 5 buttons, a ribbon cable with 6 pins is required.
In the picture you can see what it could look like. Here you can see the wiring on the top. However, it turned out that the cabling is better carried out on the underside, since the cover paper can then be better to lie flat, which will later be installed above the button breadboard.

In the following picture you can see very well how closely the components lie together. The power connection comes very close to the CPU board.
You can also see very well as the button board was installed on the CPU board, and where the micro SD-Card is inserted with the operating system and control software.

In the following pictures you can see very well that the screws for the button board and the spacers are still too long. These must be shortened so that the acrylic glass can fits over the board.  

The button and LED modules must be connected to the I/O port of the Raspberry Zero 2W.

Connection of the buttons and LED matrix to I/O port

The LED matrix is ​​connected to the following I/O pins of the Raspberry Zero 2W:  

Before connecting to the power supply, please check for short circuits with the multimeter!

What can be controlled with the buttons?

The buttons always control the active zone selected on the RoonMatrix. The zone is synonymous with output channel from Roon or the selected output channel of Spotify or Apple Music, which is provided for remote control via a local web server on the target device (Mac or PC).

To get into the Zone selection , click once on the button which points Upwards in the button cross.

You can also leave the zone selection by clicking on this button. But this also works by clicking on the button in the center of the key cross.

If you are now in the zone selection, you can use the Left and Right buttons in the button cross to navigate through a list.
This list consists of the names of the zones which are found. If the name of the desired zone is displayed on the display, select this zone by clicking on the button in the Center of the button cross. Alternatively, you can also click on the button, which shows Upwards in the button cross.

If you have left the zone selection again, you can use the buttons to control the selected device or the playing behavior of the zone:
With the Left button the song will be played which is played before. With every further click you go back in the playlist or the album.
With the Right button the next song is played in the playlist or album. With every further click you continue in the playlist or the album.
With the button in the Center you switch between playing and pause.
With the button which points Downwards , you can switch between random play and the sequential playback.

Here again as tables:

Zone selection:  

Control of the zone (standard behavior):