Based On WS2812 Mini Christmas Tree Circuit

Table of Contents

Based on WS2812 mini Christmas tree circuit project, by using WS2812 light beads packaged in 1010, the overall appearance of the mini Christmas tree is harmonious and the viewing angle is better. It adopts battery power supply + touch switch on/off + mobile phone remote control scheme, highlighting an elegant aesthetic.

The lamp board section (main body of the Christmas tree) uses WS2812 lamp beads with 1010 packaging, which are small in size and more harmonious, and have a better viewing angle. The lamp board is designed uniformly, is enough Simplified the silk screen of the lamp beads to avoid affecting the visual appearance of the Christmas tree. Using curved signal traces to integrate the traces into the design, avoiding a jarring appearance.

Control part (Christmas tree base) Achieve rich color light display effects through Bluetooth controller, also reducing development cycle. Avoid frontal wiring as much as possible to improve overall appearance. Charging interface, switch button, indicator light all placed at the rear or bottom. Circuit design adopts modular design. First, the Type-C interface and charge/discharge management chip are used to achieve battery power supply and one-key power on/off.

Schematic Based on WS2812 mini Christmas tree circuit

Schematic Main Based On Ws2812 Mini Christmas Tree Circuit

Schematic Leds Based On Ws2812 Mini Christmas Tree Circuit

Mini charging and discharging management module based on LY3205. Because the author has some OCD when designing, the author chooses to place the charging interface, switch button, and indicator light all at the back during the design process. Also, because all components of the main control board of this project are placed on the back (to enhance the aesthetics of the front), I designed a unique layered structure to achieve this.

In order to perform the power on/off operations more elegantly, this project uses a touch switch. The touch sensor chip uses the commonly used 223 chip. By using a pull-up resistor to set OLH to a low level output, the KEY pin is pulled low to control the LY3205 charging and discharging management chip. It should be noted that the touch chip needs to be powered directly by the battery (BAT+ network) in order to be used in shutdown situations. Therefore, it is necessary to choose a touch chip with wide voltage and low power consumption. We can refer to the datasheet for relevant data. Additionally, on the back of the touch sensor, the author has added a solder pad to facilitate the connection of the touch sensor to different shells.

The boost circuit uses the commonly used 3608, which will not be elaborated here. Since this project does not have high requirements for ripple, and has high restrictions on circuit volume, the author removed the voltage feedforward capacitor C7 in the PCB.

Each “leaf” has 8 beads on both sides, a total of 16 beads. 4 “leaves” have a total of 16*4=64 beads. It is recommended to use R12-16 for bead serial connection. If a bead is damaged and cannot be repaired, use the spare R17-21 for parallel connection of 4 “leaves”. When serially connected, the beads of the whole Christmas tree can achieve continuous changing effects, and when parallel connected, the light effects of the 4 “leaves” are the same.

The lamp board adopts a design of fixed pins and electrical connection reuse. It is connected to the main board by soldering the lamp board, as shown in the figure below. Therefore, it is necessary to ensure that the solder joints have been reliably connected during soldering. The four lamp boards needed are the same (of course, you can draw four different ones).

If mass soldering is needed, a “4-up panel” can be used, so that one board is “one tree”. The lamp beads of this project adopt 1010 small packaging, which has a high soldering difficulty. Beginners in soldering need to consider whether their soldering skills can be successful.

The external glass cover I chose is 8.5cm in diameter, which is smaller than the usual 10cm or larger diameter glass covers, making it more suitable for tabletop decorations. The mini size of this Christmas tree is also designed to fit this small lampshade, making it look more delicate. Software part:

Software download link:
https://play.google.com/store/apps/details?id=com.zengge.blev2

In the software, set the point number to 64 and the segment number to 1. If connected in parallel, set the point number to 16 and the segment number to 4.
On the home page of the control interface, the light bulbs can display single colors, allowing you to verify if the RGB values are correct. If the colors of the light bulbs are different from those set in the software, you may need to modify the order of the light strips (default is RGB, but my corresponding setting is GRB, using light bulbs from different manufacturers may require different settings). All boards in this project are 1mm thick!

First, solder the charging and boosting circuits, confirm that the charging and boosting outputs are correct before soldering the light board.
After soldering the light board, make sure that each light board can light up normally, and then proceed to assembly soldering.
When soldering the light board, be sure to first solder the connecting solder pads of the light board to each other, and then solder the connection between the light board and the main control board.
You can use foam tape to stick the battery to the back of the main control board, and then use metal pins to connect the WS2812 expansion board.

Charging port welding method:
First bend the two front support pieces of the Type-C port, then use solder to fix the bent support pieces to the port body.

When welding, first solder the buttons and indicator lights, and then it is recommended to use a soldering iron to add more solder to ensure that the buttons are securely fixed.

Next, tin the Type-C signal pins with an electric soldering iron, and then use a hot air gun to heat the back of the Type-C port for welding.
After completing the above steps, first confirm that the charging function is normal before soldering the four fixed pins of the Type-C port.

Control board welding method:

First, weld the main control board and the light board together, and connect them with flying wires.
Test the light function using a battery or power source to ensure it works properly.

Then, use sponge tape (thick double-sided tape) to secure the battery in the center of the bottom of the Christmas tree.

Find some hard pins of electronic components, bend them into a C shape matching the thickness of the battery.

Weld the bent pins onto the control board and trim them. Finally, weld the light Bluetooth control board to the Christmas tree main control board.
After all connections are completed, it is recommended to test it again before assembling it into the shell.
When installing, adjust the light Bluetooth control board so that the microphone aligns with the bottom hole.
Purchase the main components according to the circuit diagram. The author used the “USB Colorful Controller” module for the WS2812 controller.
The glass lampshade has a diameter of 8.5cm, and you can purchase it separately.
The battery used is a finished soft pack lithium battery with a protection board, size 602030, 3.7V.

BOM Based on WS2812 mini Christmas tree circuit

Parts	Value	Description	Quantity
C1	10uF	0805 – SMD capacitor	1
C2,C9	1uF	0603 – SMD capacitor	2
C3,C5,C8,C10,C11,C12,C13,C14	100nF	0603 – SMD capacitor	8
C4	10pF	0603 – SMD capacitor	1
C6	10nF	0603 – SMD capacitor	1
D1	1N5819	40V 1A SOD-123F Schottky Diode	1
F1	SMD0805B050TF	F0805 – 6V 500mA Resettable Fuse	1
K1	363.5 Patch side buttons	SMD Pushbutton Switch	1
L1	4.7uH	1.6A 1008 Power Inductor	1
LED1,LED2,LED3	NCD0805R1	led 0805	3
LED1,LED2,LED3,LED4, LED5,LED6,LED7,LED8, LED9,LED10,LED11,LED12, LED13,LED14,LED15,LED16	WS2812-1010	led1010	16
R1,R3,R7,R11	30kΩ	0603 – SMD resistor	4
R2,R4	5.1kΩ	0603 – SMD resistor	2
R5	1.5kΩ	0603 – SMD resistor	1
R6,R8	0Ω	0603 – SMD resistor	2
R9	10kΩ	0603 – SMD resistor	1
R10	220kΩ	0603 – SMD resistor	1
R12,R13,R14,R15,R16, R17,R18,R19,R20,R21	22Ω	0603 – SMD resistor	10
U1	LY3205	SOT-23-6 – Battery charger and motor driven control	1
U2	SD8223LB	SOT-23-6 Touch Sensor	1
U4	MT3608	Boost type SOT-23-6 DC-DC Converter	1
USB1	HC-TYPE-C-16P-CH5.90-3A-F1.3-G-02	3A 3.1 Horizontal attachment 16P Female Type-C SMD USB Connector	1