# Public Lab Research note

This is an upgrade for spectrometry. Try building it and report back how it goes.

# Spectrometer Light Tight Cover Build

by stef | 22 Oct 15:20

### What I want to do

Having removed the IR filter from my spec camera, the sensitivity increased dramatically where before the modification the spectrometer worked with the existing cover. In the new configuration the spectrometer was very sensitive to light leakage through the cover. This will work with the @stoft spec upgrades.

### My attempt and results

I cut 2 pieces of 100lb cardstock to size and a piece of heavy duty aluminum foil (not the thin stuff at the dollar store) and marked the inner lines for the bends. Don't forget the wax paper for your working surface!

I brushed on the contact cement very sparingly onto the one long edge of the cardstock and put on the aluminum foil leaving and edge exposing the paper. Brushed on more cement to the foil and attached the inside paper that was marked previously and then made a 90 degree bend.

I then bent the last 90 degree flap and brushed on sparingly the cement and glued the other side.

This is the finished cover.

### Next steps

Many may not realize that light leakage can disrupt sensitive measurement made with the spectrometer and should be aware of that possibility. I have NOT made any tests with the original spectrometer case as shipped (V03) I need to further look into the spectral bandwidth of the stock webcam without the IR filter.

### Why I'm interested

I need a stable platform to do further investigation of Ag nano particles focusing on the reflective and transmissive characteristics.

Help out by offering feedback!

### People who made this (0)

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Great build photos - I've added the upgrade:dssk tag to indicate to people that this is an upgrade that can work on the desktop spectrometer, and to prompt people to post their attempts to follow your instructions. Thanks!

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Also - do you have links to scans done with and without this light cover, in bright conditions, to show folks the advantage of additional light dampening? Thanks!

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@warren Thanks for your comments. Prior to the IR filter removal, I had no indication that there was a light transmission through the cover problem!. One can easily check as I did by wrapping the spectrometer in aluminum foil and observing any changes to the noise floor of the scan. My recent results on SW can be seen with the Cam1 NIR titles and sun sky tags. At the time I did not think to take scans of the high ambient noise levels of the scans in bright conditions. results will likely vary due to the materials used in the covers.

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