LED Display for Sousaphone

This instructable will show you how to make a display with LEDs. Count an afternoon for all the cutting and soldering.
The band's name is 'les josettes noires'. They're a girl's fanfare based in Paris.
You can listen to some of their covers here:
http://www.myspace.com/lesjosettesnoiresfanfare
You can also become a fan on Facebook:
https://www.facebook.com/pages/les-josettes-noires/15202648335
Now, let's get on with the making...

You'll need:
- a sousaphone
- 150+ LEDs (8 per letter)
- a battery (we took 3x(4x1.5V) rechargeable ones in serie.
- as many resistors (the right ones) as you have letters
- Someone good with numbers to tell you the type of resistors and battery you need
- thick (10mm) white foam board
- thin (4mm) black foam board
- a switch
- a stripe of fabric for the outside if you want
- double sided tape
- cutter
- a thick needle
- soldering iron + solder
- wire
- a sunday afternoon
- a girl's fanfarre

First, measure the sousaphone and make a nice Illustrator file with the letters and the cut-out shape you want for the outside. Reverse it and print it. It took us around 8 pages to fit everything. Rearrange the pages and double-side tape them on the thick foamboard. Draw some thicker bumps on the inside (4mm) so the ring can sit nicely and tightely on the sousaphone.
Print the letters again. Double side-tape them on the black foam board. Cut them.
Now on the back side of the ring, mark with a needle the corners of the letters. Go all the way through the thick foam board. That way, you can see where to place the letters so they fit evenly, as you had planed on Illustrator.
Use double-sided tape again to fix the letters where they belong.

Now, work on the back side of the ring. Draw your circuit as neatly as possible.
You should plan:
- where you want your LEDs to be (8 per letter),
- where you want your resistors to be,
- where you want your spare LEDs to be (more about that below)

Placed all your LEDs in serie in each letter and then all the letters in parallel. That way, you can, at some point, light all the LEDs separately, for example with an Arduino.
Also, as there are 8 LEDs per letter, some letters (like the i), don't need that many. It means you need to put them on the back side of the display. Otherwise, they're all going to have a different brightness.

We chose to have all the + at the top of the letters and the - at the bottom.

Now, punch holes with your thick needles and place your LEDs where you want them to be. Punch 2 holes per LED (one for each leg).

Place them as your diagram on the other side says.
The long leg is + and the short leg is -

Now, cross the LEDs legs together with the next one (long leg A with short leg B, long leg B with short leg C etc.) . That way, you don't have to add any wire.
Punch some holes on the back side for your resistors and spare LEDs.
Solder all that together. Don't forget to wear googles ;)

To connect all the letters together, use 2 wires (+ and  -).
Start at the end and then, using a wire stripper, strip the outside of the wire where you want to connect it next. That way, you won't have to cut it for each letter.

Put the battery at the ohter end. Add a switch in between if you want.

Stick the fabric stripe to along the edge of the thick foam board for a nice finish.

well done!
now go check out this video:
http://www.dailymotion.com/video/xds03l_les-josettes-noires-aux-marcheurs-d_music