This is my homemade spectroscope that I built for less than 1 €. I needed one becouse I am studying spectres, and for a lab research I needed to build one, So I also made this instructable for you to build your own diy spectroscope.

Step 1: Materials

The materials needed are:
1 black paperstock (0.60€)
1 old cd (free)
1 plastic separator (it was laying around, so, free)
templates (2x0.06=0.12€)
total cost: 0.72€

templates.zip
Download

Step 2: Cut the Templates

The first step is to cut the templates. Pretty self-explanatory.

Step 3: Mark and Cut the Paperstock

Now place the templates over the paperstock, mark them and cut them out.

Step 4: Mark the Folds And...fold the Paperstock

Now, place the template over the cutted out paperstock and write with a pen the folds. If you want you can also use a ruler. Then... fold.

Step 5: The Sticky Businness

The next step is to glue the template 1.

Step 6: Cut the CD

Now you need a the CD. This is the hardest part of the build. You need to cut a pizza slice like piece of CD. When I tried to cut it the reflective part of the CD (very needed) peeled off. After destroying almost the whole CD I found the best way to do it. Mark the piece you want, grab an x-acto and gently cut a "corridor" in the up side of the CD with the cut line in between, peel that "corridor" and now, applying some more force, cut a line in it. You don't have to cut it all, just to mark it. Do the same in the other side of the cd, ligning up and break the CD trhoug the x-acto mark. Unfortunatly I didn't took any pictures of the process, becouse I tried a ton of times until I found the correct one.

Step 7: Cut the Gap Pieces

Now grab your separator and using it's side, cut two rectangles that together are a little smaller than the front (5x5cm) and glue them in the front hole leaving small gap (around 1 mm).

Step 8: Glue the CD Slice

Now you can glue the CD slice in place, inside the spectroscope. But before gluing put it inside and make sure that it's in the correct position and that you can see the whole spectre using a lightbulb (with the template 2 in place, but not glued) to me, it's about 2 cm from the bottom.