Panel Arrangement

There are currently two supported arrangements for four 64x64 panels in Piomatter --serpentine and --no-serpentine

No-Serpentine

In this arrangement all four panels are oriented alike.

The benefit of this is that view-dependent differences in pixel color are a non-issue. 

However, a rather long run of IDC ribbon cable is required to make the connection from panel 2's output to panel 3's input, approximately 50cm for a 3mm pitch matrix panel.

If you have a long enough cable, go for this arrangement.

Serpentine

In serpentine arrangement, the two bottom panels are oriented upside down.

The benefit of this arrangement is shorter cable runs.

The downside is that there are view-angle dependent color shifts visible between the upper and lower pairs, particularly when lighter colors span the break, which can cause a blueish line to appear.

In the attached screen photos, you can see the cause of this is the physical arrangement of the RGB LED trio per pixel. Blue is at the bottom of the pixel, so it is perceptually stronger where the two bottoms rows meet.

The build in this guide uses serpentine arrangement since I didn't have a 50cm cable on hand.

Connector Bracket

Plug in the IDC cables and then mount the back bracket. 

Press the bracket onto the panels so the registration pegs are nicely seated, then screw the bracket in to place using M3 screws.

Note, the bracket is designed to accomodate both panel arrangements, so there are holes that will remain un-used -- check for brass threading before screwing into a given hole.

Edge Joints

Next, screw in the edge joints to align and secure the panel edges. Note that the side joints (printed in magenta filament here) have cutouts in them to accommodate the data sockets.

Matrix Bonnet

Follow the silkscreen polarity markings and screw in the two sets of power cables to the terminal block as shown here.

Pi Mount

Use four M2.5 screws and nuts to create mounting points for the Pi 5.

Fasten the Pi with nuts or short standoffs so that the Matrix Bonnet can still be connected.

Mount Pi to Panel

Plug in the IDC cable from the Matrix Bonnet to the input of panel 1.

Screw in the Pi tri-corner mount to the panel.

Then, screw in the other tri-corner mounts. The keep the display centered in the frame, along with the frame spacer.

Plug in the four power connectors.

Frame Mounting

Place the acrylic panel in the front of the frame.

Set the four corner spacers into place as shown, so the wooden frame spacer will seat into them and hold them flush to the front of the frame.

Carefully place the matrix display into the center of the frame.

Speaker Prep

Press fit the speaker into the printed speaker holder.

Fit the speaker into the frame, then plug the USB cable into the Raspberry Pi.

Two Power Supplies

Plug in the USB C power to the Pi and the 5V center-positive 10A DC power cable to the Matrix Bonnet.

Back Panel

Dress the cables to exit below the panel 1 corner, then cut out a little mouse hole in the back panel for them using a hobby knife.