LEDs and RBBB on Motorcycle

Hey everyone,

I've been working for a while now on getting everything in order to put a knight Rider"ish" LED set up on my motorcyle. I'm planning on using a RBBB with a Atmega168 that I'll load with my light programs. Connected to the RBBB via pins 2 and 3 will be a RF remote to trigger the lights to change with each press of the remote. And to have enough outputs for the lights I'm using two 74HC595's in series. I've included a schematic (my first one ever so please excuse it) of what I think I have to do.

I do have a question though. Do I have to connect all the grounds together seeing as I'm using three different voltages in different parts of the set up? As it is now there's +12 from the bike, +9 from the 1st regulator, and +5 from the reg on the RBBB. Thanks a million for any suggestions!

Yes all the grounds must connect together as shown in your drawing. Nice drawing by the way.


It appears that you really only need 5 outputs. Did you leave some LEDs out of the schematic?

If the LEDs use less than 100mA per string, you should look into the TPIC6C595: it's similar to the HC595, but has output transistors built in.


You have drawn all your LEDs backwards! The way to remember it is that current flows (from positive to negative) in the direction of the arrow on the symbol. This goes for transistor arrows (emitter), too.

Ran: Yes I'm actually having 16 banks of LEDs. For space and sanity reasons of doing this quick schematic I chose to just lable the like banks together with the 1&16, 2&15 ect.. as seen on the top. It's not a proper one to send to any manufacture house or anything...just my first attempt ever at a schematic to ask members here about. And I'll look into the TPIC6C595's.

Anachro: Thanks for the tip. I knew that in real life but schematic wise I just clicked LED on my program and that's the way it popped up. I'll take care to flip them for furture drawings.

Thanks guys