11-02-2004 21:42

Rickertsen2

Re: pic: IR captured in photo (4 IR LEDs @.1A DC ea)

Yup make yourself an array of them and you have a flashlight that only your camera can see. = really bootleg night vision

12-02-2004 14:02

Damian Manda

Re: pic: IR captured in photo (4 IR LEDs @.1A DC ea)

Ehat camera did you use for this picture? My camera can hardly see anything when pointed at the beacon.

12-02-2004 16:14

KenWittlief

Re: pic: IR captured in photo (4 IR LEDs @.1A DC ea)

any old camcorder will see IR remotes and LEDs

try turning the lights off, or hold the LED closer to the camera - BTW this is a good way to check and see if they are working

12-02-2004 22:22

Joe Ross

Re: pic: IR captured in photo (4 IR LEDs @.1A DC ea)

Somebody else posted that newer cameras have better filters and block more of the IR

13-02-2004 16:38

Dale(294engr]

Re: pic: IR captured in photo (4 IR LEDs @.1A DC ea)

Camera used: Olympus 3040, digital, 3 megapixel, flash off, macro focus on

This photo was taken with an IR LED powered from a
5 VDC voltage source drawing .11A (33 ohm kit current limit resistor)
i.e. 100% ON duty cycle....
to make it easy for the digital camera to see.

See my other IR Beacon photos in the gallery
showing the much dimmer (but visible) LED illumination when pulsed/burst
<1 mS burst of 40 KHz pulses, & low duty 100Hz rep>

emitter 0:
pulsed at 40 kHz (50-50 duty square wave)
burst for 40 cycles = 1mS (total ON time = 500uS)
and 100 Hz repetition rate (total Off time = 9500uS)
500*100/(9500+500) = 5% ON duty time

use emitter 1 (to improve cameras ability to see IR a bit)
80 cycles = 2mS (total ON time = (.5*2mS) =1000uS)
and 100 Hz repetition rate (total Off time = 9000uS)
1000*100/(9000+10000) = 10% ON duty time