LED Matrix Assembly

Version Differences

Beta Kits (early 2021) came with the V0.2 LED MATRIX.

Pre-Production Kits (late 2021 & early 2022) come with the V0.3 LED MATRIX. These omit:

1) The QWIIC connector (you can add it yourself JST SM04B-SRSS-TB from Digi-Key or similar)

Assembly Steps

The LED Matrix assembly is very simple. There are three items in this part of the kit: LED Matrix Board, 8-pin header, [optional] diffuser sheets.

STEP 1: Cut the header into four pairs

The 8-pin header needs to be cut into four pairs of pins. Each pair of header pins will go at each end of the 20-pin rows on the left and right edges of the LED Matrix. The middle 16 pins will remain open so the Core Board can slide through those holes and connect indepently to the Logic Board.

STEP 2: Solder the headers

Trim the short-end of the header so it barely sticks through the board. Flush is preferred. If you initially solder each pin flush with the top of the board, you can come back and give them a quick touch of flux and solder to make a nice domed top so they aren't sharp. Like this:

To hold the header pins in place, you can use the Core Board as an alignment fixture.

You can also use the backside of the Logic Board, or the Logic Board sockets if you have those installed already.

Whichever method you choose, the goal is to keep the headers perpendicular to the bottom of the LED Matrix board. Final final assembly position is like this:

Yes, that black wire is a bodge wire on the Beta Kits (V0.2 LED MATRIX. I failed to route the Digital Ground wire all the way to the header row. This path supports optional I2C-based accessories at the Qwiic port and the 4-pin header holes at the top and bottom edge.

After soldering, clean off any flux with isopropyl alcohol.

STEP 3: Battery Pack Installation

The Core64 can accept the battery pack on the top of the logic board or the back of the LED Matrix.

The Core64c can ONLY accept the battery pack on the back of the LED Matrix.

For the Core64, I recommend putting the battery pack on the Core64 Logic Board, and those instructions are provided in the Logic Board Assembly Section.

If you choose to install them on the LED Matrix (and you must for Core64c), the battery cells may fall out of the holder slightly since they are not held in by gravity. You may need to secure them with tape, depending the brand of cells you buy.

The battery pack includes double-sided tape so it can stick to the board. Install it in the position bounded by the four inner triangle marks denoted "Battery Corner" on the silkscreen. The insulated wires are routed through two small non-plated holes (strain relief) next to the B- and B+ silkscreen at the upper right corner on the backside of the board. Then route the wires back through the B- and B+ holes from the LED side.

The solder connection is made on the battery pack side shown here:

Here is what the wires look like on the LED side:

At some point you'll probably notice the Core Board has 8 pins which are labeled, but not used or connected to anything. They are the top and bottom pairs of holes on both the left and right edges of the board. From left-to-right, top-to-bottom: LSIG/USR1, 5V0/GND, USR2/USR3, +BATT/5VUSB. These pins are active in the Logic Board and LED Matrix, but unsused on the Core Board. They are labeled on the Core Board for reference/expansion if you come up with something clever.

LED Matrix assembly is complete for now. Later, in the Final Assembly chapter, you will trim the header pin lengths to match the Core Board header pin lengths.

You can power things up right now (Teensy® + Logic Board + LED Matrix) and you should see all of the LEDs illuminated in blue, at a fixed brightness. The LEDs may start to cycle through colors in later versions of firmware. The orange LED on the Teensy may blink or be on. Either batteries or USB will work as a power source. With USB the switch needs to be in the down position, with batteries the switch needs to be in the up position.