Summary of Making a mini LED Christmas tree
This article details the construction of a mini LED Christmas tree for children, featuring 22 multi-color and red LEDs controlled by a PIC12F683 microcontroller using Charlieplexing. The build involves creating a foam board base, covering it with green construction paper, and wiring the LEDs on the backside to five I/O pins via a prototyping board with current-limiting resistors.
Parts used in the Mini LED Christmas Tree:
- PIC12F683 microcontroller
- 22 multi-color LEDs
- 11 Red 5.0mm LEDs
- Black foam board (0.2 inch thick)
- Green construction paper
- General purpose prototyping board
- 100 Ohm resistors
- Header pins
- Sharp pin
- Christmas shape stickers
Christmas tree control circuit
This section describes the electronics part of the project. It uses the PIC12F683 microcontroller that operates at 4.0MHz using the internal clock source and drives 20 LEDs through 5 I/O pins (GP0, GP1, GP2, GP4, and GP5) using the Charlieplexing technique. The 20 LEDs are connected to the five Charlieplexing signal lines (named A through E) as shown in the figures below. Multiple color LEDs are chosen to make the Christmas tree colorful and attractive.
– See more at: http://embedded-lab.com/blog/?p=8116#sthash.HFMkB7wL.dpuf
Construction of tree
First of all, make a paper layout of the tree and stick it on a cardboard or a foam board using glue. I am using the 0.2″ thick black foam board from Dollar Tree. Mark the places where you want to place LEDs on your Christmas tree. Next drill two holes (approximately 0.1″ apart) for LED legs at each marked LED position. Then cut the foam board along the layout of the tree. These steps are illustrated in the following pictures.
– See more at: http://embedded-lab.com/blog/?p=8116#sthash.HFMkB7wL.dpuf
For more detail: Making a mini LED Christmas tree
- How many LEDs are used in this project?
The project uses a total of 22 LEDs, consisting of 11 red LEDs along the edges and 11 multi-color LEDs in the body area. - What technique is used to drive the LEDs with limited pins?
The Charlieplexing technique is used to drive 20 LEDs through only five I/O pins. - Which microcontroller operates the circuit?
A PIC12F683 microcontroller operating at 4.0MHz using its internal clock source controls the circuit. - How are the extra two LEDs connected?
LED 21 is connected in parallel with LED 16, and LED 22 is connected in parallel with LED 20 to ensure symmetry. - What material is used for the tree structure?
A 0.2 inch thick black foam board from Dollar Tree is used as the base for the tree layout. - Where is the wiring performed?
All LED wiring is done on the back side of the tree using a small piece of general purpose prototyping board. - What is the purpose of the 100 Ohm resistors?
The 100 Ohm resistors are placed in series with the five Charlieplexing signal lines on the prototyping board. - How are the LED holes prepared on the front layer?
Holes are extended across the construction paper by inserting a sharp pin through each hole from the back side to the front.
