I found this Instructable about how to make your own night vision camera. It seemed to be a fun project, so I decided to give it a try.
The first step is to remove the infrared (IR) filter from the camera. I broke my first camera attempting to do this. I was far more careful with my second one and successfully removed the filter. The little blue chip is the IR filter:
This is how the photos look with the IR filter removed:
After successfully removing the filter, the next step was to build an IR LED array to be used as a light for the camera. With a little bit of help, I was able to laser cut a perfect array of holes for the LEDs. Following the instructions, I assembled the LED array and turned it on, only to be disappointed by an incredibly dim light.
What went wrong? Here’s the point where I confess that I am relatively new to electronics, and so there are certain lessons that are yet to be learned. I wired the LEDs incorrectly. I got a second batch and wired them together.
And still the array was too dim. It was time to really understand how the circuit of the array worked. There was something more at play here. I found a really cool LED array calculator online that helped me get to the bottom of my problem. I had to examine the LEDs more closely. The instructions use infrared LEDs from Radio Shack, which have a 940 nm wavelength, a 100 mA forward current and a 1.28 volt forward voltage. My first two attempts used LEDs that had a forward voltage of 1.5 volts, which meant that the LEDs were not getting enough power. I ordered a new set of IR LEDs with a lower forward voltage of 1.2 volts and assembled the array for the third time.
The third attempt was better. With the new array, I was able to capture photos in the dark!
I did a little test to get a feel for how well the camera worked. First, I set up a small scene to photograph. I was interested to see how the camera could capture color and detail. Here is the control photo, taken with my normal camera:
First, I took a photo with the lights on. The room was somewhat dark, so the photo did not come out very clear:
Next, I took a photo with the lights off, about one foot away from the objects. The detail was still somewhat clear, although differentiating colors was not really possible.
The second photo was taken from two feet away. At this point, some objects are no longer visible.
The final photo was taken from three feet away. The objects are almost imperceptible at this point.
Although it was fun to build this, it isn’t very practical for real-world use. The major problem seems to be the power, as the 9 volt battery drains very quickly and is not strong enough to power many high-power infrared LEDs. If I go back to this project, the first step would be to build an array with a larger power supply and brighter LEDs. In the interim, I will just have to be content with taking nighttime pictures of things up close.