Removing IR Filter From ESP32-CAM

I’ve been playing around with the ESP32-CAM modules a lot lately, and after spending some time searching through pages of code, I think I’ve finally got a handle on configuring the camera and getting it to start up cleanly.

With its boot time being about a second and the price being as low as it is, I think there are tons of applications for it. Everything from an always-on security camera to an occasionally used trail/wildlife camera, eye/brain/wifi for a remote-controlled car or robot… all kinds of things.

I want to put some cameras outside to catch the various animals that are leaving tracks in the snow, and these things are so inexpensive that they’re aalllllmost disposable. That’s not to say that I plan on putting them in situations where they’ll be ruined, but if one gets gnawed on or water gets to it, it won’t be the end of the world.

One thing that the stock camera can’t do, though, is see well in the dark. Even with bright IR illumination, the IR filter in the camera does a good job of keeping the picture stubbornly dark. Back when the Raspberry Pi camera module first came out, I fought with the IR filters in a couple of them, so I figured I’d take a shot at removing the filter from one of the OV2640s that came with the ESP32-CAM. Turns out it wasn’t too tough, although it took some patience.

PLEASE NOTE THAT THIS IS ONLY FOR THE CAMERA SHOWN IN THE PICTURES BELOW. I DON’T KNOW IF THIS PROCEDURE WORKS FOR OTHER CAMERAS.

OH, AND ALSO PLEASE NOTE THAT I’M NOT RESPONSIBLE FOR ANYTHING YOU DO, SO IF YOU WRECK YOUR CAMERA OR CUT YOURSELF OR BURN YOUR HOUSE DOWN OR WHATEVER, THAT’S ON YOU. BE CAREFUL!

First, remove the camera from the ESP32-CAM module by lifting the latch that’s holding the connector in place. Take note of where the glue is on the lens – it shines a little more under a light than the plastic does:

ESP32-CAM lens

After the camera is loose from the module and you’ve located the glue, very carefully and gently run a sharp knife in the seam between the lens barrel and the camera casing:

ESP32-CAM IR lens removal

Once you’ve cut the glue, grab the lens barrel with one finger and thumb and the casing with the other and gently turn the barrel counterclockwise. If it doesn’t turn, go back and run the knife through the glue again. If it does turn, you’ll be rewarded with a view of the camera sensor…

ESP32-CAM IR lens removal

… and you’ll be able to see the IR cut filter too:

ESP32-CAM IR lens removal

The filter in this particular camera is held on by a very thin ring of plastic and possibly some glue. I slowly shaved the plastic away until I got right down to the filter, then very carefully pried the filter off with the knife:

ESP32-CAM IR lens removal
Still broke the filter, though…

After that, it’s just a matter of making sure there’s no dust on the inside of the lens or on the camera sensor, then very carefully threading the barrel back into the casing. It is really easy to cross-thread it, so take it slow and be careful. If all goes well, you should end up with a put-back-together camera:

ESP32-CAM reassembled

One of the other advantages of cutting the glue and being able to thread the barren in and out is that you can adjust the focus on the camera now. Want to look at something nearby? Back the barrel out a bit. Something far away you want to see? Spin it in a bit.

Anyway, put the camera back in the ESP32-CAM and flip the lever down on the connector to secure it all. Voila, you now have an IR-sensitive camera!

Oh, one of the things that sometimes goes unmentioned when talking about making your camera “see in the dark” is that after you remove the IR-cut filter, your camera will no longer work very well in colour, particularly where there is a lot of extra IR light bouncing around (i.e. daytime). The colours will not look normal and it will seem like the picture is out of focus. You can fix that by putting an IR-cut filter back into or in front of the camera, but I just want to watch animals wander around in the dark so B&W is just fine for me.

Here’s the difference removing the filter makes. Same remote, same button (3), and same camera settings. Here’s before I removed the filter:

Before IR filter removed

And here’s after:

After IR filter removed

A bit of a difference! I’m looking forward to trying this out and seeing which wavelength of IR LEDs it will be the most sensitive to.

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