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  • Author Author: fvan
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Testing Pi NoIR with IR LEDs

fvan

When I got my Pi NoIR camera, I didn't have any IR LEDs to play with, so instead I used my TV's remote control for testing (Road Test review).

This was enough to demonstrate the functionality of the Pi NoIR, but it wasn't a permanent solution.

 

In the mean time, I managed to get my hands on a couple of IR LEDs.

 

The voltage drop across the IR LEDs I got is approx. 1,5V for a current rating of 60mA, meaning that with a 5V power supply I could put a resistor and 3 LEDs in series.

The resistor's value would have to be approx. 8 ohms (0,5V / 0,060A), but the closest resistor value I had lying around was 10 ohms.

 

I ended up with following circuit of two times three LEDs, in order to place three LEDs on each side of the camera board:

image

 

I downloaded a camera holder that I found on thingiverse (Raspberry Pi Camera Holder by gryphius - Thingiverse), modified it in Sketchup to be able to hold the LEDs and printed it.

imageimageimageimage

 

The circuit was powered with a separate 5V supply for this test, but ideally I'd like to power this from the pi itself.

Perhaps someone knows if it's ok to use the 5V/GND pins on the GPIOs to do this ? I'll have to look into this ...

 

With the LEDs powered, and the Pi NoIR running, it was time to take pictures and videos in the dark.

 

These are the results (at night, with all lights turned off except for power switches, etc ...):

 

raspistill -o file.jpg

imageimage

 

raspivid -o file.h264 -t 20000

 

 

The raspivid utility saves .h264 format files. Some programs need this in a .mp4 wrapper to use, which you can do in several ways. One is to use "MP4Box" which is in the 'gpac' package.

 

sudo apt-get update
sudo apt-get install gpac
MP4Box -add filename.h264 filename.mp4

(info from: http://elinux.org/Rpi_Camera_Module)

 

pi@raspberrypi ~ $ MP4Box -add testnoir2.h264 testnoir2.mp4

AVC-H264 import - frame size 1920 x 1080 at 25.000 FPS
AVC Import results: 594 samples - Slices: 10 I 584 P 0 B - 0 SEI - 10 IDR
Saving to testnoir2.mp4: 0.500 secs Interleaving

 

Using these IR LEDs, I was able to light the room up to 1.5 to 2m away with a limited field of vision.

 

Perhaps I should try some high power IR LEDs and compare the results, but that will be for next time image