CD Spectroscope in a Box, Spectrograph

by jeandeau

23K2413

Intro: CD Spectroscope in a Box, Spectrograph

While many others have done this project, I worked at optimizing the view angles and publishing these. CD Spectrograph in a Box is a simple educational one evening project. Everything you need to know should be evident in this one photo, but following steps give space for commentary. Note: a spectroscope is to view spectra, a spectrograph is a recorded image (photo) from a spectroscope, a spectrometer measures spectral wavelengths.
Check out DoWatts DVD Spectra instructable.

STEP 1: Supplies

*Masking tape or duct tape. Duct tape is better to keep light out from cracks. Otherwise,use a black felt marker on tape to keep all stray light out of box.

*Single edge rasors or a breakable thin rasor blade work well. For a children's safety version, use the opposite edges of a credit card cut in half. It will save you a lot of money!

*The LED's are fun to observe as is a compact flourescent light. The laser pointer is dangerous and should be used with care and only to illuminate a translucent plastic bag covering the slit.

  • Any CD that you don't mind damaging

STEP 2: Construction

Glue a cardboard plate 70mm from the top and keep it horizontal, Especially from side to side! This is just to support the CD which you may hot glue or tape in place. If you place the plate lower than the recommended 70 mm, the CD must be a little farther from the far edge of the box and the viewing hole must be proportionalely farther from the front edge. Try to keep the angles correct. The incident angle is about 13 degrees from perpendicular and the viewed angle is about 47 degrees from perpendicular or 43 degrees from the horizontal. Note that the angle of the diffracted light is NOT the same as the angle of the source (incident)light.
A hole 10 mm x 20 mm is cut far enough from the front edge to allow taping two razor blades in place 1 mm apart or less. A viewing hole 25mm square is cut 95 mm from the slit. This hole can be slightly oversize for ease of viewing. The light guard is not essential but it is definitely helpful. Hot glue was used in much of the construction. Again, it is not essential but made things easier.

STEP 3: Cereal Box

Cut slits in the box to support the CD. The slits must be placed identically on each side of the box. CD slits should be 1 mm to allow space for the CD to slip in without distortion. CD slits are 70 mm down from top of the box. Illumination slit is 15 mm from front edge. Viewing opening is centered 95 mm from the illumination slit.

I welcome links to similar projects to be posted here.

13 Comments

Jim_teacher 15 years ago

Is it possible to get a photo of what this thing does? Or does the spectra appear on the inside of the box? i'm totally confused, was looking for cool lamp type things... maybe it could be modified to cast a spectra on a wall as in a night-light? Hey thanks!

masonrulz 14 years ago

i got some pics:P didi make ir right? is this how the spectras supposed to look?

jeandeau 14 years ago

Great photos! Excellent contribution!  The five strong separated bands of color from red to violet suggest to me, you used a CFC lightbulb as a source of illumination. Is that correct?  I am curious to see a photo of your spectroscope.  You may be entertained to see the spectra emitted by Lexus HID headlamps.  They emit a large multitude of distinct color lines.   This indicates a lot of research and selection of a variety of chemical selected to flouresce in the gas mixture.  These may change as they warm up.

masonrulz 14 years ago

here are the images of my spectrograph

jeandeau 14 years ago

Thanks, good show.  The alum foil is excellent for blocking out light.

masonrulz 14 years ago

thank you very much:D

PS: the jiantpatch of foil on the back is because i cut the hole in the wrong area first XD

masonrulz 14 years ago

thanks:D ill put up a photo of it in like 5 mins

jeandeau 14 years ago

Beauty!  Yes that is how they are supposed to look.  I am very impressed by the photo.  I posted a reply on the spectroscope in a box comment string

jeandeau 15 years ago

great idea on the photo; I'll see if I can do that and add it. Yes, the spectra appears inside the box when viewed through the viewport (the shield part added on top). Light source may be a diffuse source such as a lightbulb or cloudy sky, position box so light shines through the opening on the top left of the box in the direction shown by the lines drawn on the box shown in this instructable. build the box and you will find it easy and fast to find the position to hold it. Obviously the light shines on the CD placed as shown in the instructable. If light is from a point source such as the sun or a LED, you may wish to put wax paper or white plastic bag over the slit opening to diffuse the light. This makes viewing a little easier. If a bulb is placed at the slit and a converging lens is placed just over one focal length from the CD and in the same direction as shown on the side of the box, you will have a spectrograph projector. Do check out DVD Spectra. It's easy and fantastic. I've done it.

Kiteman 16 years ago

That's it? Wow.

Spectroscope climbs up to-do list.

joejoerowley 16 years ago

Cool! Great Instructable! Thanks Joe