POV Light Display on Bicycle Wheel

The project produces POV displays by using an Atmel ATTiny861 microcontroller to control 48 LEDs on a bicycle wheel.

The concept behind the construction is to produce a very visible display that can turn ON and OFF automatically, have enough memory to store full resolution bitmaps, and have enough processing power to dynamically generate bike computer style displays. The first version was a hand built board containing a magnetic reed switch, a resistor array, 14 LEDs, and a single ATTiny26 microcontroller. Although ATTiny26 is very versatile, the ATTiny861 is a strict superset including 8k of program memory which is better for storing full resolution bitmap patterns.

To give high resolution patterns, there are 48 LEDs to total installed with 24 on each side of the board and can be seen from both sides of the bike. A series of 74×373 ICs connected to an 8bit bus on the microcontroller is used to control the LEDs without having any resistors. There is plenty of time to spare to figure out what should go there since all 48 LEDs can be updated in 20-30 microcontroller cycles as opposed to shift registers.

Rest of the project