The circuit is super simple…just six wires…but the tiny enclosure necessitates some unusual build steps. We’ll get into the details on the next page, but for now, in simplified schematic form, this is what we’re aiming for:

Some points of interest to remember:

• Do not assemble the LED matrix and driver board yet…some unusual steps are required if making the pendant design.
• For the pendant, the LiPoly Backpack is flipped and installed “sidecar style” rather than the usual position where it’s stacked on top.
• A couple of wires need to be soldered directly to pads on the back of the Pro Trinket rather than the usual through-hole vias.
• There’s a trace that needs to be cut on the LiPoly Backpack to enable the power switch. This is shown on the next page.