3D Christmas Tree Soldering Kit - 2019

By Jamal Bouajjaj


This project is a PCB soldering kit in the shape of a christmas tree. The 3D parts of the projects comes from connection the main PCB and 2 "auxilary" PCB thru a right angle connector. The kit has been designed with some SMD and THT parts. If you plan to use this design as a kit for people who have no/minimal soldering experience, it is recommended to pre-solder the SMD parts before giving the board to them for them to solder.



Project's folder:

Click the GitHub folder below to access the project's files, which include the KiCad PCB files, the Gerber files, and the Autodesk Inventor CAD files.

Google Drive Link

Theory of Operation:

The circuit is based on a 555 timer and a 4017 decade counter. The 555 timer is set to operate as a astable multivibrator. The clock output of the 555 is connected to the 4017 decade counter. This counter then incremently turns on a "channel" at a time. Each "channel" signal is connected to a Darlington array in order to drive the potential 4 LEDs connected per channel. Each "channel" output has 2 LEDs connected to it in the main board, and 1 in each auxilary board. The auxilary boards are not required for the operation of the main board, but is recommeded to solder them on, mainly because they look cool.


Image 1

PCB Parts:

This kit has some THT and SMD parts to be soldered (THT means through-hole, and SMD means surface-mount).

Main Tree
PCB ReferencePart DescriptionPackage SizeQuantity per Board
U2ULN2003 Darlington Transistor ArraySOIC-161
U34017 Decade CounterSOIC-161
F1250mA PolyfuseTHT1
J3Micro USB Right AngleWürth Elektronik 6141051507211
J45-9V Battery Connector2-pin 0.1" header1
C2 0.1uF Decoupling CapacitorSMD-08051
R14.7KΩ ResistorTHT1
C1100uF CapacitorTHT1
D1-D155mm LEDTHT15
R2-R16330Ω ResistorSMD-080515
Auxiliary Tree
PCB ReferencePart DescriptionPackage SizeQuantity per Board
R1-R7330Ω ResistorSMD-08057
D1-D75mm LEDTHT7
J18-pin Right Angle 2.54mm HeaderTHT1


Here is the PCB's schematic (The first one is for the main tree, the second is for the auxilary tree):

Schematic of Project 1 Schematic of Project 2

Technical Diagrams:

Here is some diagrams relating to the project:

PCB Drawing PCB Drawing PCB Drawing PCB Drawing PCB Drawing PCB Drawing PCB Drawing


The PCB is designed to be screwed or tight-fitted into a case at the buttom of the board. I have designed such case, which you can find in the project's GitHub folder.