Removing IR Filter From ESP32-CAM, Part II

**UPDATE (2020-05-08): I did a little bit of math and realized I was only running the IR illuminator at about a quarter of a watt. After a bit more poking around and squinting at part numbers, I’m pretty sure it can run at almost 10x the power. I will look into this further sometime soon.**

Shortly after my previous post on removing the IR-cut filter from the OV2640 camera that comes with the ESP32-CAM, I put the ESP in a safe place… so safe that I lost it.

I found it again a couple of days ago and finally got to tinkering with it this evening, with the plan to see how well it worked in the dark.

I changed the following settings from the defaults for all of the pictures taken with the ESP in this post:
– Frame size: 1024×768 (XGA)
– Gain ceiling set to 3
– Special effect set to 2 (greyscale)

Without the filter, the colours were all wrong and it was a little harder to focus. This is normal but a little annoying, so I set the image to greyscale. Here’s the first image I took, looking at the bird feeder as the sun was on its way down on the other side of the house:

ESP32-Cam with no IR filter
I tried to set the focus at where the bird feeder is. Not sure if I was entirely successful…

It’s not too bad. Things look a little weird – the trees, sky, and grass all look like they’re from a really cheap dream sequence. Two hours and fifteen minutes later, the sun had set but there was still plenty enough light for the camera:

ESP32-Cam

Twenty minutes later, the streetlights were all on, there was very little glow in the sky, and the image started to get pretty noisy:

ESP32-Cam

Another 25 minutes and it was dark:

ESP32-Cam
The bright dot is a light the next block over

So, with ambient light in the suburbs at night, the ESP32-Cam isn’t a stellar performer. This is not a high-end CCD rig.

I have a couple of inexpensive little IR illuminators but they’re so inexpensive that they didn’t come with specifications and I can’t find datasheets for them. I ended up using an LM317 to limit the current to about 125mA. I’m pretty sure they can go higher but figuring out how high is a project for another day.

IR Illuminator
Yep, one of the many, MANY illuminators out there that look just like this.

Here’s what that thing running at 125mA did:

ESP32-Cam
Well, I can see… something. Not much, though.
ESP32-Cam
After shining it around to find the best angle, I can juuuust make out where the bird feeder hook comes out of the ground.
ESP32-Cam
Yep, it’s definitely on…

Not so good. Or… was it not too bad? It’s not like I went out there with one of those 400 LED yard illuminators – this was a single diffused LED that’s pulling just over half a watt. Maybe I should revisit this with something that puts out a little more oomph.

The next thing on my list to check was how well it worked indoors. To test this, I put the camera and illuminator at one end of a hallway, closed the door, and turned off all the lights. My phone picked up a bit of light under the door at the far end of the hall, about 12 feet away:

Dark hallway with phone

And here’s what the ESP saw:

ESP32-Cam

And with the same illuminator (at the same power) turned on:

ESP32-Cam
You can even see the yellow sticky note I put on the door. Can’t see the smiley on it, though.
ESP32-Cam
My shirt is black under normal light.

Having the IR confined to an area where it can bounce around and not just be lost to the night makes a big difference. With a better (or more than one) source of IR, the ESP32-CAM may well make a decent indoor night camera. Tweaking some of the camera settings may improve things, too.

So… not the best performer, but for the cost (I think I paid nine dollars for this particular one, camera and all) and the sheer number of features that the ESP32 series has, I find it a pretty attractive little device.

I think the next ESP-ish things I want to look at are getting some pictures of the animals that wander through the yard at night, and maybe trying this particular experiment again with a bigger/better IR illuminator.

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