* Build

** Materials and costs

| Component           | Qty/measurement |   Cost |
|---------------------+-----------------+--------|
| Ikea LACK table     |               1 |   5.00 |
| Raspberry Pi 2B (?) |               1 |  35.00 |
| WS2812b LEDs        |           15x15 |  30.00 |
| 5V/3.3V buffer      |               1 |   0.50 |
| 5V Power supply 18A |               1 |  26.77 |
| Acrylic 5mm         | 560mm^2 + sides |  50.00 |
| MDF 3mm dividers    |           14+14 |  70.00 |
| Various parts       |                 |  30.00 |
|---------------------+-----------------+--------|
| Total               |                 | 247.27 |
#+TBLFM: @>$3=vsum(@I..@II);%.2f

** Steps

*** Drawing the lines
Begin by drawing a cross on the table, and recurse until the center of
each cell is draw.

[[./images/hires/step-0.jpg][./images/thumbs/step-0.jpg]]

*** Adding LEDs
Cut the LED strip in pieces and paste them with hot glue on each
center on the table. Connect the LEDs back together with three wires
per piece (5V, GND and DI/DO). Pay attention to wire each DO
(Data-Out) to a DI (Data-In) on the neighboring LED.

[[./images/hires/step-1.jpg][./images/thumbs/step-1.jpg]]

*** Dividers
The dividers where tricky. My first thought was cutting it by hand out
of cardboard. But I'm not really precise, and doing it 28 times (14
horizontal and 14 diagonal) would have been difficult.

After some looking around for other options I found [[https://www.snijlab.nl][snijlab.nl]] Which
is a great online service that will laser cut SVG files. It does come
at a price, but the result is beautiful and very precise. A
side-effect of the laser cutting are the burnt edges. This actually
gives a really nice effect as the black enhances the edges.

**** TODO add inkscape svg files here.

[[./images/hires/step-2.jpg][./images/thumbs/step-2.jpg]]

*** Raspberry Pi and Power
Controlling the LEDs is a Raspberry Pi (model 2B, other models will
also do). The Pi's GPIO pins operate at 3.3V, the WS2812b expects a 5V
signal. To bridge this gap a =SN74HCT125N= 3.3V<->5V buffer is used.

**** TODO add diagram here.

[[./images/hires/step-3.jpg][./images/thumbs/step-3.jpg]]
[[./images/hires/step-4.jpg][./images/thumbs/step-4.jpg]]

*** Power on!

It works \o/

[[./images/hires/step-5a.jpg][./images/thumbs/step-5a.jpg]]
[[./images/hires/step-5b.jpg][./images/thumbs/step-5b.jpg]]

*** Acrylic
Ordered, cut to the right size, at [[https://www.dokter-plexiglas.nl/][Dokter Plexiglas]]. Glued together
with special Acrylic glue.

[[./images/hires/step-6a.jpg][./images/thumbs/step-6a.jpg]]
[[./images/hires/step-6b.jpg][./images/thumbs/step-6b.jpg]]