Glittering PCB Art Christmas Wreath

PCB ART for Glittering LED

If I ask what a PCB is, most people will think of a board with thin wires and electronic components on it. This time, I'm going to change my taste a little bit and make Christmas decorations by painting on PCBs with PCB art, which uses PCBs as a canvas and wiring (copper foil), resist, and silk printing as paints.

Since the PCB can be used to design circuits, I would like to incorporate not only ART but also a circuit with sparkling LEDs to make a Christmas decoration.

I'll show you how to make it as well.

Christmas Wreath Drawing

After much deliberation on what kind of Christmas decorations to make, I decided to make a Christmas wreath. The first step is to draw a design of a Christmas wreath with a pencil, and make a detailed drawing of each ornament inside the wreath. We will decide on the design.

Creating data using PhotoShop

We will use PhotoShop to draw pictures based on the pencil drawings. To make a substrate, the resolution should be 10cm x 10cm and 300DPI.

The setting of the PCB to be made this time is red resist PCB, silk is white, and copper foil (Cu layer) is gold plated. For this reason, we can use red, white, and gold colors.

In addition, a layer of red resist on top of copper foil gives a bright red color, while a layer of red resist on top of no copper foil (the bare substrate) gives a dull red color. Also, the bare substrate without any resist or copper foil looks dull and yellow.

Thus, the available colors are the five listed above.

Using PhotoShop, extract only three types of areas from the wreath illustration: Cu layer, resist mask, and silk, and convert them to black and white images.

Cu layer: extract bright red, gold, and silk areas
(In this case, we also included the silk area, but it is better not to include it, as it makes it more difficult to place the components).
Resist mask: extract gold and dull yellow areas.
Silk: extract only white areas.

Creating a Footprint Library in KiCad

Use the bitmap component conversion function of KiCad.

Cu layer

Load the BMP of the Cu layer,

Format: Pcbnew(.kicad_mod file)
Image Options: Check for negative
Layer to use: Surface layer solder mask (no Cu layer, so choose this one for now).

With the above settings in place, "Export".

In the Footprint Library, add the folder you exported.

Open the exported data using the Footprint Editor. The F.Mask layer is purple, so we will change it to the brown Cu layer.

Double-clicking on the purple area will bring up a window for changing the layer. Change from F.Mask layer to F.Cu.

When all the areas have been changed to brown F.Cu, the Cu layer is complete. Save.

Resist mask

We will also use the bitmap component converter for the resist mask and export the BMP with the same settings as before.

When you open the exported data in the Footprint Editor, it is OK if it is purple.

Silk

Load the silk BMP,

Format: Pcbnew(.kicad_mod file)
Image Options: Check for negative
Layer to use: surface silk

With the above settings in place, "Export".

If you look at it in the Footprint Editor, it is light blue. This is OK.

Substrate it

Click on the IC shape icon in the right column, and load the three footprints you just created one by one on the layer.

Cut lines to trace the outline, and your design board is complete.

Use the 3D viewer to check the finished image. It's quite beautiful.

Glitter Circuits

Since we are using a printed circuit board, we would like to incorporate a mechanism to make the LEDs sparkle.

This time, we made the system super simple. た。We used an inexpensive ATTINY13A microcontroller and connected LEDs to all the IO pins. Each LED is programmed to light up with a random twinkle.

The random function is a simple one, using lightly processed XOR and shift registers. To save power, we also lowered the clock to 125 kHz, the lowest possible. In our experiments, it ran at about 0.5mA on average, including the LED lights. I think the LEDs will keep sparkling for a week or more.

Project and program Files are below.

wreathTiny13A

A coin cell battery, microcontroller, and resistors are placed on the back of the PCB.

The PCB design is complete

Arrival !!

Oh, oh, oh!

It's quite beautiful. It's hard to tell from the picture, but the gold is very beautiful.

The front side is a wreath pattern, and the back side is a circuit. す。The back side is also nicely done.

Assembly

The parts are very simple. LED, resistor, battery box, microcontroller, and switch.

It is a DIP component, but it will be soldered to the back of the board like a surface mount component.

Finally, solder the LEDs and the board is complete. The number of parts is small, so it doesn't take long. It is easy to make even for beginners.

Tie the ribbon and you have a Christmas wreath.

Done!!!

This time, I made two types of Christmas wreaths, a white one and a brown one without silk printing.

When you turn it on, the LED will blink like this. We left it on for about two weeks and it is still glowing. It seems to have a pretty good battery life.