IR blinking flashing in low light

[will_h 0]

Hi all,

 

I have a four cam setup with low end board cams with IR illuminators.

 

The illuminator on a couple of cams blinks on and off when the light sensitive diode that controls the IR LED's is covered up, and at night.

 

Surely it should just come on in low light and off in daytime? Instead it blinks at night, giving an intermittent image.

 

I've tried turning what I assume is a calibration resistor on the illuminator ring but it does absolutely nothing to the way the diode responds to light.

 

These generic no-name low end board cams have no discernible model number and it's hard to get info on them, can anyone link me to some useful info that might help me?

 

I've just moved into the house and the system was already installed, total newbie but learning as I go....

 

Thanks,

Will

[zmxtech 0]

you get what you pay for, why waste time on shoddy equipment ?

 

The LDR usually bias's a transistor of some kind...... they are very simple

circuits.

 

z

[Soundy 1]

Is the camera itself staying on while the LEDs are blinking?

 

Try metering the voltage at the camera, see if it drops significantly when the LEDs come on - my bet is that the current draw from the LEDs is causing the voltage to drop to a point that the LEDs shut off... then when they're off, the voltage goes back up to the point the LEDs can turn on again... and around goes the cycle.

[rory 0]

Some cameras come with a blinking LED such as the recent Eclipse 599Ts. In the case of that camera one would just cut the yellow wire, or remove power from the yellow wire. Wire colors can differ and this may not even be the issue you are having but it is just a thought.

[will_h 0]

thanks for replies, yes the camera is staying on throughout blinking but the auto iris is constantly having to adjust to the changes and its less than ideal. Its like intermittent night vision. Blinks on and off consistently about once a second, maybe a bit faster. Would be good if I could just force the LED's to stay on permanently as they prob don't use much power.

 

I will look for a yellow wire but I don't think its a blinking IR device because it works fine when the LEDs stay on, which happens when light levels are low. It only blinks when I cover up the diode with the tinted dome glass of the enclosure or my finger...

[rory 0]

Ok I also went to a job recently where the IRs were blinking and powering the camera down and back up again fixed it temporarily but it did it again later that day, so I changed the power supply (the client had individual plug in power supplies) and it was fine then - so check the power also.