The 2021 ornament was an evolution of previous years ornaments and the first 3D one! It had been an idea for a while to make interlocking PCBs but required a couple of months of planning to make it work properly. A series of 3 interlocking PCBs were used – one main one with battery contacts, MCU, regulation and ambient light sensors and the other 2 just with LEDs. All LEDs are in parallel on opposite sides of the boards.
A series of contacts at the top and bottom are used to connect the signals between the boards and also provide structural support to hold everything together. Quite intensive to manually assembly them all but we produced 10 in time for the holidays. There’s a slot cutout in one PCB so you can insert a single AA battery in the middle.
Fred Temperton 