since April 2001

Technical Information

 

 

Smart Balls
Cover
Illumination
Battery
Processor
Memory
PlugInStation
Communication
Programming

 

Smart Balls

Weight
230g
Diameter
70mm
Colour
white
Plug
3 poles

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Cover

The balls are poured with two materials. Outside we use a soft, translucent silicone layer. Inside there is a hard core, which protects the electronic circuits.


left: Smartball version 1, right: outer layer, hard core, complete ball version 2

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Illumination

The balls are lighten up with high light emitting LEDs in the colours red, blue, green and yellow. It is possible to mix other colours (fast changing between two or more basic colours). There are four LEDs of each colour, so a very good illumination of the whole surface is achieved.

Colour
mcd at20mA per LED (30°)
mA (4 LEDs)
Red (626nm)
900
110
Green (575nm)
1750
65
Blue (473nm)
450
130
Yellow (592nm)
1700
125

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Battery

Three rechargeable NiCd cells are built in, which can be recharged with the PlugInStation. 650mAh results in a very long illumination time. In show mode (full power) the battery lasts about 8 hours. In practice mode you can juggle easily 16 hours or more. You can either recharge the balls slowly in about 12 hours or as an emergency fast in 6 hours. In the normal slow and save mode the balls will first be fully discharged.

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Processor

A Microchip PIC16C58 controls all different actions. It is run with a 4MHz oscillator, which allows fast enough instruction execution and colour mixing. Routines carried out by the processor:

read and write program memory
communication with PlugInStation
start different programs
execute juggling ball instructions (such as show colour, listen to sensor, ...)
mix colours and fade between colours
detect catches
...

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Memory

Next to the processor there is a EEPROM 93LC86 device on the circuit. Program instructions, initialise bytes and colour tables are stored here. With an instruction width of 16 bits it is possible to store about 1000 instructions. Several smaller programs can be located after each other.

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PlugInStation

This is where we keep the balls when we're not juggling. But it is more then just a storage place. There it's possible to recharge the ball, to reprogram them and to choose and start different juggling programs. In the actual version are plugs for sixteen balls, each fitted with a LED display showing the actual identification number of the ball plugged in.

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Data transfer

Data is transferred over a RS232 interface with 19200 baud between a computer and the PlugInStation.
Between the PlugInStation and the balls we use a kind of serial protocol with up to 9600 baud.

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Programming

The SmartBall programming language includes about 50 instructions which make it possible to program every desired pattern (within the possibilities of having a timer and catch detectors).

(... to be completed...)

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