If you would like to see more pictures of what the bag looks like, visit my site: tardistrekkie.tumblr.com

Hello there! If you're looking for the ultimate bag to show your geek pride, you've come to the right place! In this instructable, I'll give you step-by-step instructions on how to make an awesome bag that will literally have people stopping you on the street to ask where you got it! Just remember to mention me when you tell them about it!

Remember, before you buy anything, make sure that all the specs meet your requirements! This is merely a guide , so all of the final decisions need to be made by you! Read all of the instructions (both here and for all of the parts you will be using) before you begin! And because you will need to use scissors and an iron to make this, be very careful not to burn or cut yourself (or someone else) and get help if you need to!

Thanks, and don't forget to rate!

Step 1: Materials

Parts I already had:

Iron - for the iron-on fabric. I actually have a mini-iron, but I'm sure a normal iron will work, too.
Scissors - for cutting!
Cardboard - to protect the fabric and plastic from the heat of the iron
Sewing machine - to sew in guides for the transparencies (to keep them at the correct height)
Photoshop - to make the patterns nice for my printer
Paper cutter - to cut paper and fabric in straight lines
Printers - laser (for black and white) and ink-jet (for color)

Parts I needed to buy:

Messenger bag - $15 from http://bit.ly/pRAnbU
A4 size Panel with power transformer- $90 from http://bit.ly/pt2hAG
Battery Pack - $34 from http://bit.ly/pteLnq
Black Iron-on mending fabric (I recommend at least 12" long) - $3 from a fabric store
Transparencies (for color inkjet printers)- $28 from http://amzn.to/qzzmML
Transparencies (for laser printers) - $14 from http://amzn.to/qoslVG
Black velcro - found at any craft or fabric store
Fray Check - $4 from a fabric store
Fabric Marker to mark cutting guides (make sure it comes off easily! - $3 from any fabric store

Final Cost: Aproximately $200

Step 2: Modifying the Messenger Bag

1. Find a messenger bag! Any kind will do. I chose mine because it had a plain front and looked decent.
2. Measure your bag. I knew I wanted to use an Electroluminescent panel, but I didn’t know which size I wanted to use, so I had to figure out the exact size of the space in my bag’s flap.
3. Based on your measurements, purchase an EL Panel. Make sure that your measurements of the panel include any borders around the lighted area before you purchase! For example, I made sure to ask the seller on ebay for the exact dimensions of the panel (in mm) to ensure that it would fit inside the flap on my bag. Turns out I only had about a 3mm tolerance to work with!
4. Before cutting into your bag, first make facsimiles of the panel as well as the size of the window you want to make out of cardstock so that you can position the window properly on the flap. (The size of the window on my bag is 10"x 7.5" because it ensured that an 8.5x11" pattern would not fall out)
5. Mark the area you will cut with a washable fabric pen, then cut the window with a sharp pair of scissors
6. Before the cut edges can fray, go over them with some Fray Check and let it dry
7. After the cut edges have been sealed with the Fray Check, decide how you want to finish the edging (described in the next step ).

Step 3: Edging and Finishing of the Fabric

Here is how I sealed the cut edges:
1. Cut 1/2" strips of mending fabric (make sure the strip is longer than the edge you are covering
2. Fold the strips in half, then mark where the corners will be on the folded part of the strip
3. Use a 45-degree triangle guide to cut the edges at the correct angle
4. Position the strips on the edges of the window and carefully adhere the fabric with an iron

Note: Make sure your iron is hot enough to adhere the edging to the bag, but not so hot that is melts or damages the fabric. Also, make sure you protect any areas which are not meant to be ironed with a towel or piece of cardboard.

After the front window has been completed, it's time to make the slit for the panel so that it can be easily put in and removed
1. Flip the bag so that you can get to the back of the flap
2. Chose a location which is above the smaller window and large enough for the width of the panel
3. Mark and cut the slit for the panel, then finish the edges with more of the iron-on mending fabric
4. Attach Velcro at your discretion to ensure that the panel will not fall out easily

Make sure everything fits!

Step 4: Making the Patterns

Transparencies:
1. Find a pattern you like that is black and white (I used Google)
2. Make sure that the pattern is sized to fit inside the window
3. Follow the instructions on the transparencies to ensure good printing
4. If the pattern is too light, try printing another copy and layering the two.
5. For multiple layers, adhere the transparencies in the corners

The pictures for this step show a transparency I printed out by itself, then when it is in the finished bag.

Also, you can layer colored transparencies behind black and white transparencies to give your patterns a cool background!

Paper:
1. Find some good quality black cardstock
2. Trace your pattern on the paper
3. Cut it out!

Note: If your cutout has words or "floating parts" you can attach the paper cutouts to a transparency. The Star Trek cutout is a perfect example.

Step 5: Final Assembly

1. Insert the EL panel (with pattern) inside the front flap through the slit you made in the back of the flap
2. Attach any cables/cords to the panel, then place the power converter and battery wherever you like.
3. Turn it on!

To change the pattern, just remove the current one and replace it!

I hope you enjoyed reading this instructable! Please leave me feedback if you have any questions or you want to say hello!

Step 6: Extra Instructions

This small set of instructions is meant for people who have access to a paper cutting machine such as a Cricut as well as a program such as Sure Cuts A Lot (by Craft Edge).

1. Find a pattern you like which is easy to cut
2. Follow the instructions from the software as well as the machine to ensure a good cut
3. Cut out your pattern! I used black cardstock because it is easy to cut and it blocks out the light from the panel well.

An example of this is the Aperture Logo attached to this step.

Good Luck!