OK, finished helping another thread I was doing some drawings for. I'll sketch something else up here next.

 

OK, here is how I would do it...

Depending on the exact Vf of the LEDs would determine with block schematic you would use (shown on bottom of drawing).

Drawing corrected.

 

Bill, looks like your LEDs are backwards.

 

<sigh> Brain Farts!

Thankee Kindlee. Time to turn my act around (again). I'll just modify the original.

 

Hi Guys,
What kind of transistors are being used in this circuit? Howdy Bill I'm kinda following this thread and going to proto board when your are done ( for another project) lol Thanks Jim

 

Anytime I don't specifically name a BJT you can bet it is either a 2N2222A or a 2N2907A, depending on polarity. The ones in a metal case can handle 0.6 W, and they have fairly gain.

 

so which should i use, 2N2222A or a 2N2907A?

if you get bored, write up an idiot guide to this lol

 

The transistors in question are NPN, 2N2222A. Plastic types (AKA PN2222A) will work fine for this application. Radio Shack sells a 15 pack for a fair price (unusual for the shack).

I need a firm Vf for the LEDs you have. You probably need to measure them, this I can help with too. Then I can define those blank resistors on the schematic.

What kind of board are you planning on using to build this?

 

what would you suggest? i was thinking just regular pcb from somewhere like ebay or the shack

 

The 15 NPN transistor assortment that Radio Shack sells usually contains:
5 - 2/PN2222 transistors
5 - 2/PN4401 transistors
5 - 2/PN3904 transistors

 

They are pretty interchangeable, though I prefer the PN2222A types (better specs). I bought a package of a 1000 from BG Micro not too long ago.

To the OP, when you refer to the PCB, I'm more curious about the display unit and how you are going to do that. The breadboards Radio Shack sells will work OK for the electronics. I tend to draw the circuits, I can do it here, though it will take a while.

If you have never done this kind of work it will be the hardest part.

 

Bill, what kind of software do you use to make your circuit drawings? They always come out so nice and easy to read.

 

Bill, what kind of software do you use to make your circuit drawings? They always come out so nice and easy to read.

He uses MS Paint, and patience.
Here is a link to his blog entry on PaintCad:
http://forum.allaboutcircuits.com/blog.php?b=49
There is a .ZIP file that contains symbols that you can copy/paste into your own schematics.

 

Drawing circuit boards takes a lot more patience than schematics (for me). I've gotten pretty good on both. Lots of practice, don'tcha know.