08/01/01

 

    With many profuse Thank-You's to my co-worker Jeff for giving me a clue about electronics, and Marcus for taking the time to give me some sample circuits, I've actually got something constructive going on here. :)  I've been reminded of Ohm's Law ("Oh yeah.."), and learned that LEDs work more as a function of current than voltage. 

     I know many easier circuits exist, but my knowledge of NAND gates and their use is rough enough that I decided I'd rather build something I can test with the kit I have on hand; if I wanted to build the supreme flashing circuit I'd put a lot more time and experimentation into it, but what I want is a supreme ship, and therefore will run with what I have so that I may test it with minimal parts purchase / experimentation.

     The Radio Shack kit has a sample circuit for a strobe light, which I constructed but there were a number of problems - it flashed too quickly, and it simply wouldn't work with a white LED.  In talking with Jeff I learned enough that I could modify the circuit they had (and take out some superfluous parts) to not only make it work with a white LED, but slow it down.  I increased the resistance before the capacitors (1) so they wouldn't charge as quickly, decreased the capacitance of (2) so it would work with a white LED, and increased the capacitance of (3) also to slow the flash rate.  Here's what I came up with:

 

1 - 690k Resistor

2 - 0.1 uF Capacitor

3 - 200uF Capacitor

4 - 2SC945 NPN Transistor

5 - 900CT:8 ohm Transformer

6 - White 3.0mm LED

 

 

 

 

 

     With the above configuration, the white LED flashes at an excellent approximation to the Voyager's running lights.  The only problem I have is that if you examine the LED carefully, you'll see it start to glow before it flashes.  Going through fibre, however, that's not much of a concern.

    

     Now I need to design the circuit as a whole - I need a 3v transformer to power  the whole thing - half of it will be the circuit that powers the full 3v / 20 mA LEDs as well as the 2v (unknown mA) smaller LEDs, and the other half will be the flashing circuit that powers the white LED fibre driver.

 

     A trip to RadioShack.com is in order, to get the specifications of the smaller LEDs, acquire green, blue and red LEDs and get the mA rating of the white LEDs.  I also need to acquire more fibre cable (though I can't get that from the store, need to go somewhere else).

 

     Here's my shopping list: (23+ LEDs total)

 

white LEDs- (2+?)
     Fibre drivers (2)
     Large windows (21) (can use ambient light, number not specific)
          2+2+2+2+2+2= 12 (upper saucer)
          5 (lower saucer)
          4 (engineering hull)
     
red LEDs (bright, big)- 4
     Warp nacelles (2)
     Impulse engines (2)

red LEDs (pinkish, small) (6)
     port indicators
          saucer = 2
          engineering = 2
          nacelle = 2

green LEDs (small) (6)
     starboard indicators
          saucer = 2
          engineering = 2
          nacelle = 2

blue LEDs (big, bright) (5)
     warp nacelles (2 ea)
     main deflector dish (1)