400 LED Disco Ball

A disco ball with 35cm diameter, consisting of 400 LEDs that can be programmed through an Arduino.

A paper balloon 35cm diameter.

3 X 5meter, 30led/m, WS2812B addressable led strip.

STM32F108 board (blue pill) (with its programmer).

Power supply: 5V, 12A at least (I used an old PC power supply).

1. The led strip must be cut in sections of 12 and 13 leds (16 sections of each length)
2. It is useful to mark the "equator" of the sphere.
3. each led section has IN and OUT points.
4. the 12 led sections are placed with IN on the top of the sphere, the 13 led sections are placed with OUT in the top of the sphere. The strip sections are placed alternating: 12 led - 13 led- 12 led - 13 led -....
5. Can be helpful to start placing 2 13-led sections in opposite positions, then the 2 sections in the middle of them, then the 4 sections in the middle, and so on until all 16 13-led sections are placed. Then, the 16 12-led sections can be placed between the already placed sections (attention: in reverse order IN-OUT)

The STM32 module must be programmed. The source code is in file "Disco.ino".

Arduino IDE is used to compile and load the code with the STM32 programmer.

1. Select one IN at the top of the sphere as the master IN.
2. the OUT of this "first" section must me connected to the IN of its adjacent strip. All section must be connected OUT to IN, to form a single line.
3. All GND must be connected to a single point,
4. All 5V must be connected to a single point.
5. ATTENTION: the final current will be at least 10A, so the power wires must have the appropriate thickness.
6. The STM32 module must be connected to 5V and GND.
7. PB7 of STM32 module must be connected to the master IN.
8. Connect to the 5V power supply and enjoy!