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The Microchip 16F630 is the only active logic in
the MiniPOV. It contains timer code that blinks the 8 LEDs on and
off at a precise rate, as well as the image map of what pixels should
be on when. When turned on, it simply displays the stored image
map repeatedly.
Of course, there are also 8 high-brightness, red
5mm LEDs. Other color LEDs can be used but only if they have a Vf
of less than 3V. All 5mm red, orange, amber, and yellow LEDs
should be fine. There are also some low voltage green LEDs but most
are 3.4V or higher Vf.
The resistor values should be chosen so that Ic
through each LED is ~20mA. For example, with 2 x 1.5V alkalines
and red 2.1V Vf LEDs, the resistor value is (2*1.5 - 2.1)
/ .02 = 45ohms. The closest 5% value is 47ohms.
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