Make Something Else







Hardware history
last edited: September 22, 2004

Microcontroller-centric design  

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.

Parts List  

When we made kits, we had a free source of LEDs, so these are not well specified, and also allowed us to keep costs under $400 total. Any LED with a brightness of 1000millicandela (mcd) or higher should be just fine. 5 cent LEDs are unlikely to be this bright.

The Panasonic AA batteries are sold in 48 packs for $10 each on on a regular basis.

Name Manuf. Part Number Description Required # Total Cost for 100 kits Distributor
IC1 Microchip 16F630-I/P Microcontroller 1 $120 Digikey
IC1* Generic ICS-14 14 Pin Socket 1 $10 All Electronics
R1-8 Generic 470QBK 47 ohm resistors 8 $8.70 Digikey
U1 Generic SBH-321AS 2 AA Battery Case with switch 1 $60 Digikey
D1-8 Generic   5mm LED 8 $100 Various
PCB         $125 Advanced Circuits
B1-2 Panasonic   AA Alkaline 2 $40 eBay  
Total         $465