Layers are formed by arranging 24 LEDs into a circle shape. The anodes of each LED in a layer are soldered together using 0.7mm tin coated wire which helps to form and hold the circle shape.
With 16 of these layers then stacked to form the finished tube shape. The cathodes of a column of LEDs are soldered together using 0.9mm wire.
Only one layer of LEDs can be active at one time. By using persistence of vision which very quickly switches between layers, the viewer is fooled into seeing all the layers active at the same time.
To control the display I used a mbed NXP LPC1768 micro controller. The LEDs are driven using one TLC5947 from Texas Instruments, four A2982's from Allegro MicroSystems and two 74HC238 from NXP. These surface mount components and supporting components are soldered to a custom design and home etched PCB.