I just added some LED's to some of my buildings. I didn't put them in all of the buildings because I wanted some contrast in the lights. Does anyone know why the LED'S flicker in a video but not in real life?
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Over the top cool layout!!!!!
The LEDs appear to flicker because in real life the do, but so fast your eye cannot detect it. Because video cameras have a shutter speed themselves at certain speeds the the two will overlap. The camera has a much slower "frames per second" but it will catch the one moment when the LEDs are "off" - and since the camera's speed is slower, the time the LED is "off" appears to be greater "on camera." I shoot a lot of corporate video and often have to show computer screens and we have to fiddle with the camera's shutter speed to get the blinking to stop.
Pulses of voltage to illuminate them? Your eye cannot pick them up.
Almost like watching the news when they would show a TV screen on camera.
LEDs as such do not flicker. They are DC devices and produce a continuous output. I am guessing that you are probably powering yours with AC or else some kind of switching regulator that does not provide true DC. So you end up with pulses, as Lima suggests. You might try a better power supply, or else a big capacitor.
Unless your cursed like me and can see 60hz flashing. Some car manufacturer's tail light LEDs strobe in my visible detection range.
That web page is very misleading.
The statement
It is a fact that all LED lights naturally flicker at a rate of approximately 60 Hz per second.
is just wrong. If you power an LED from a battery, there will be ZERO flicker.
Later on, the article states
Why do LED lights flicker? They flicker because of the rapid on/off cycling of electricity as it pulses through them.
This statement is correct. But it is a statement about AC power, not about LEDs themselves.
If you want your LEDs to not flicker, it can certainly be accomplished.
Very cool! Where did you get your LED's?
Chief Bob (Retired)
Can we create white light, filtering LED light, using celofan foil?
AG.
Very cool! Where did you get your LED's?
Chief Bob (Retired)
The LEDs appear to flicker because in real life the do, but so fast your eye cannot detect it. Because video cameras have a shutter speed themselves at certain speeds the the two will overlap. The camera has a much slower "frames per second" but it will catch the one moment when the LEDs are "off" - and since the camera's speed is slower, the time the LED is "off" appears to be greater "on camera." I shoot a lot of corporate video and often have to show computer screens and we have to fiddle with the camera's shutter speed to get the blinking to stop.
All good. The simple rectifiers we're using to drive the LEDs probably produce a clipped, and saw tooth DC signal that starts at zero, goes positive and then back to zero again. It doesn't go negative since the rectifier is blocking that polarity. I too see LEDs "strobe" on car taillights. This is may be caused by the same effect since the car's electrical system may be deriving it's power from rectified AC from the alternator. I'm not sure how the battery and alternator interact. The battery may be just going along for the ride once the engine is running. If the alternator is doing all the work, then there would be a pulsating DC just like when using an AC power supply. I don't notice the LEDs flickering on my layout lighting. I'm using a panoply of AC adapters scrounged from old phones and computers.
I just researched my own question. The answer is, the alternator powers the electrical system when the engine is running. Therefore, it will be rectified AC and suffers the same problem of a simple rectification system, pulsing DC that's reflected in the LEDs flickering.
You can buy these on Amazon, I found them through another OGR forum thread from last year,,, they work great, I didn't need to put the full 12 VDC to get the brightness I wanted, mine actually looked great around 9 VDC..
Go to this link they are on sale on Amazon right now,,,,, I may actually buy some more at this price less than $10 bucks ....
http://www.amazon.com/gp/produ...00?ie=UTF8&psc=1
About 10 years ago, some engineers at CMU came up with a trick in which a stick of LEDs was flashed rapidly using a microprocessor in such a way that if you scanned your eyes past the stick , it would scan over your retina and you would see an image or some text. If you looked directly at the lights, you would only see the lights flickering a bit. Really cool. The "Noah's Ark" funhouse at Kentwood Park used these as a novelty for a few years.
BTW: The cheapest way to buy LEDs is to get one of those 5-meter rolls of cuttable LED strips from eBay. You get 300 lights for a few dollars, and you can cut them at every third light. For a few dollars more you can get the RGB version and a remote control that lets you dial in any color.
Hi Spence • I am due for a hair cut........ lol
Just bought some of the LED strips. They're a real bargain since they already have the resistors in place. All of my DC sources are 12 V so they'll just go right in. Good find... thanks guys.
I'm using them too as you can see in my Imperial Hotel. One lights the entire building, and is cool enough I can just mount it right to a cardboard roof.
Just bought some of the LED strips. They're a real bargain since they already have the resistors in place. All of my DC sources are 12 V so they'll just go right in. Good find... thanks guys.
The strips also work well in passenger cars and cabeese, you can mount them on the roof of the cars and with a small rectifier for ac and a capacitor the flickering is gone.
Ray
Spence,I don't think you have a problem.As long as they are not flickering when you are looking at them,what differance does it make?JMO.Nick
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