Wednesday, December 4, 2013

Remove infrared filter from D-Link DCS-930L

The DCS-930L is a cheap wireless camera that lacks infrared LED:s and has a infrared filter in place to block all infrared light. I googled around and found Microfrost blog (http://www.microfrost.com/2011/06/21/d-link-dcs-930l-infrared-capabilities/) and thought I'd removing the infrared filter from the new composite lens assembly that my camera has. It turns out it's not that hard, see the process in images below.

The camera case pops open quite easily and the camera board is loose inside (no screws)

First I tried unscrewing the lens but it was glued to the lens holder so I just ended up destroying the plastic.

When removing the cover, take care not to break the little snaplocks like I did..

Instead of trying to remove the lens I just removed the whole assemly. It's mounted using some sort of silicone so I just pulled it off with a pair of pliers. The infrared filter is now clearly visible in red.

I removed the filter by pressing a tiny screwdriver along the edges of the filter, shattering it and removing the pieces/dust. (removed pieces of the filter is visible in the picture)

To the right you can se the silicone still left on the PCB where the lens assembly was mounted. After removing the infrared filter I put the lens assembly back in the silicone "holder" on the PCB.

And fastened it with some hot glue.


Unfortunately I ended up with this image. Lots of stains/spots and a very short focus distance. So I removed the lens assembly again and saw that there was alot of tiny dust particles on the image sensor. These could easily be removed. To fix the focus I had to move the lens closer to the image sensor. This meant that I had to carve away some plastic at the bottom of the lens assembly (the part that touches the PCB) with a small knife.

I put the lens back and the focus distance was better and the spots gone. There is a slight blurring in the right hand side of the image due to a small scratch I happend to make in the lens when removing the IR-filter.
That's it, now the camera can see infrared light. You can also add an external infrared illumination source if you want even better visibility. Check Microfrosts post about this: http://www.microfrost.com/2011/06/21/infrared-led-assemblies/