Heart & Star

Make a badge using gimmick of star shape change to heart shape. The point is arrangement of LEDs.

This circuit is using Charieplexing, that is using 5pins drived 20 LEDs,

1st prototype using 3mm LED.

Prototype using chip LED.

Whole surface coated with UV resin. So, switch moved to back side.

MPU moved to back side too. Only LEDs on surface.

0603 chip LED changed to 0402.

Arrangement of LED

And again changed to 0201 (0.65mmx0.35mm).

Left 0603, center 0402, right 0201.

I tried to decorate by decreasing the size of the board to φ30 mm.

I challenged to make the substrate smaller.

And I made it slim by making it a tear-shaped one.

φ34 →φ30 →φ20 → 17mm x 23mm

I made the battery smaller to make the board smaller.

It is CR2032  to CR1220, that is, φ20mm to φ12mm.

I tried challenging multicolorization.

0201LED: I added green LED and white board.

0402LED:  I tried to 5 colors.

I made width slim 13mm.  17mm x 23mm →13mm x 31mm

I tried challenging slim figure.