Solar Bauble - Solar Powered Festive DIY Decoration
The Solar Bauble kit is a great geeky way to celebrate the festive period! The LEDs flash for a while in the evening and the unit recharges during the day.
A small solar panel charges some capacitors during the day. Then at night the unit will start to randomly twinkle, with eight red and green LEDs around the circuit board. Firmware on the microcontroller has been designed to be very low power, and, with fully charged capacitors, the LEDs should flash for up to 2 hours.
It’s designed as a fun and interactive way introduce solar power and improve soldering skills. Here is a little video of the twinkle in action:
It does need to be placed on a SUNNY window. Preferably south facing or that gets direct sun for some of the day. (It will not charge well from indoor lighting). It will need at least 1-2 hours of sunlight to fully charge.
Note: This is a DIY soldering kit, with relatively easy soldering required. It best if the constructor has some experience soldering.
Parts Supplied:

|
Item |
Ref |
|
Ref |
|
0.47F Ultra Capacitor |
C1, C2 |
Printed Circuit Board |
PCB |
|
100nF Decoupling Capacitor |
C3 |
1k Ω Resistor |
R1 – R4 |
|
5mm Red LEDs (loose) |
D1, D3, D5, D7 |
100 kΩ Resistor |
R5 |
|
5mm Green LEDs (in a bag) |
D2, D4, D6, D8 |
1 MΩ Resistor |
R6 |
|
1N4148 Diode |
D9 |
10 kΩ Resistor |
R7 |
|
ATTiny85 Microcontroller (programmed) + 8 pin IC Holder |
IC1 |
Solar Photovoltaic Panel (5V, 30mA) |
SC1 |
|
Suction Cup Hook |
N/A |
Transistor 2N3906 PNP |
Q1 |
This design is open for non-commercial use. A full set of PCB design files, instructions and the firmware is available in the project GitHub repository here:
https://github.com/curiouselectric/solarBauble
Note: Only suitable for people over the age of 8 years old, due to small parts.
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