Ever need to find a live fibre port in a patch panel?
Ever need to figure out if you've got a polarity problem with your fibre SFP?
A simple modification to a USB webcam will make it sensitive to the IR light from your optical connections. Using webcam software on your PC, you'll be able to see the otherwise invisible light.
Finding live ports becomes extremely easy - they will show up brightly. It's also pretty easy to figure out the media type (e.g. figuring out if your connection is SX or LX) by looking at the image.
Step 1: Tools & Equipment
1 Logitech C210 webcam
#0 or #00 philips head screw driver
Soldering iron with a small tip
About 10 minutes
Step 2: Removing the IR Filter - Open the Camera
The camera within the C210 is actually quite sensitive to the IR (or near IR) light used in Ethernet optics. Unfortunately, this sensitivity can result in your webcam images looking 'washed out'. To compensate for this, Logitech install an IR filter.
Once the filter is removed, the camera is again very sensitive to IR light. After doing this mod, the camera will still work, but its images won't be as clear when used as a webcam.
1) Open the camera
Using a screwdriver, remove the two screws on the back of the webcam.
Step 3: Remove the Main Board
Once the camera is open, you can unscrew the main board. Two more screws. Be careful not to damage anything as you free it from the housing.
Step 4: Remove the Lens
The lens and filter assembly is held onto the main board with two more screws. Remove these and pull the lens off the main board.
Step 5: Remove the IR Filter From the Lens Assembly
The IR filter is a small square on the rear (i.e. circuit board) side of the lens. The filter material is a sharp, slightly red tinted glass.
The filter is held in by glue.
To remove it, run the tip of the soldering iron along the sides where the glue is visible. The filter can then be removed with a pair of tweezers. Be careful - it's prone to cracking and likely to be sharp.
While you've got your soldering iron handy, you may wish to remove the green LED (listed as D1) on the PCB. This LED will pollute your images with light and make it harder to see the infrared Ethernet signal.
Step 6: Refocus and Reassemble
You can now reinstall the lens assembly and fasten the board to the camera housing.
Before screwing the front cover on, it's time to refocus the camera. I wanted items that were about 50mm away to be in sharp focus. This makes it easy to find the live pair in a patch panel.
The focus adjustment is the screw on the front of the lens assembly.
From there, put it back together and test it out!
Step 7: Usage
When looking at a 1000BASE-LX connection, you should see the RX line as being a reasonably bright purple light.
When looking at a 1000BASE-SX connection, you'll see the RX as being a FANTASTICALLY bright purple light.