Public Lab is an open community which collaboratively develops accessible, open source, Do-It-Yourself technologies for investigating local environmental health and justice issues.
This page documents assembly and use of the Public Lab **Countertop Spectrometer** -- a pre-assembled, pre-calibrated spectrometer with a built-in dimmable light and stage, based on the [Desktop Spectrometry Kit](/wiki/dsk), which was offered as a reward during the [Public Lab DIY Spectrometry Kit Kickstarter](http://kickstarter.com/projects/jywarren/public-lab-diy-spectrometry-kit)
Although designs and ideas have evolved since the Countertop Spectrometer was developed, it is still a robust way to measure absorption in liquid samples.
Some of the countertop spectrometers experienced some damage during shipping, and if this happened to you, please contact **email@example.com** to get replacement parts! Sorry!
Although the spectrometer is assembled when shipped, you need to attach the arm to the base (it is detached for shipping) and bolt on the sample stage.
**Arm:** Plug the arm into the socket at the back of the base (not the light bulb socket!). Be careful not to pinch the USB cable -- you can tuck it into the arm tube or the base, and it will be pushed out of the way. Be careful not to tug on the cable -- you could unplug it from the interior of the spectrometer (it goes to a USB webcam). If this happens, you can keep disassembling the arm until you find where it unplugs and plug it back in.
**Stage:** The stage is the piece of clear acrylic plastic in your box (it has a brown paper protective cover which you can peel off). Place the stage between the two black plastic clips on the spectrometer's arm. Using a screwdriver and your fingers, insert and tighten the bolts through both clips and the stage's matching holes.
**Do NOT place the stage too low or the light may melt or burn it if left on high!**
**Bulb & cables:** Screw your light bulb into the socket firmly. Plug in the spectrometer and turn on the dimmer by pressing it down. Plug the USB cable into your computer.
###Retrieving your calibration
If you ordered this in the above-mentioned Kickstarter, your spectrometer was pre-calibrated at the "factory". To retrieve the calibration and begin taking calibrated data, follow these steps:
* First, register on this site, and log into [SpectralWorkbench.org](https://spectralworkbench.org) with your new username.
* Next, navigate to: https://spectralworkbench.org/lookup/
* Enter your calibration code, which is written on a round sticker on the bottom of your device.
Calibrations can potentially drift over time, but re-calibrating yourself is easy. You'll need a fluorescent light bulb, which you can put into your light socket (turn the dimmer all the way up). Then [follow instructions here](/wiki/spectral-workbench-usage#calibration).
##More guidance and support
For more on usage, troubleshooting, and support, check out these pages:
* [Spectral Workbench](/wiki/spectral-workbench)
* [Spectral Workbench Usage](/wiki/spectral-workbench-usage)
Here are some photos of the inside of the spectrometer to show how it's built. Be careful with the wiring!
The wiring layout:
Roughly place the parts and align the holes:
Screw it together:
Obviously we skipped some steps - one was cutting holes for all the parts and screwing the light socket around the hole cut in the outlet faceplate. But this shows most of the important bits. You can see more photos here: http://publiclab.org/notes/warren/04-17-2013/final-countertop-spectrometer-design...