I have mypancam on the birdfeeder outside.The camera is inside the window. Since it’s backlit and I can’t adjust the exposure for backlighting, I needed to add lights to the front side to light up the feeder. I bought 20.00 worth of LED lights and put one on each side. I now see a moving BANDING effect of light and dark bands that move from top to the bottom of the screen slowly. If there a way to reduce exposure/shutter speed of the camera?
See photo- notice the pillar on the left has thebands. They also run across the entire image and at times the suet area is LIGHT and then DARK as the bands move down over it. I see them on phone as well as both computer monitors.
What’s happening is that your LED lighting is flashing in sync with the AC powerline. It’s too fast generally for the eye to see, but the cameras sees it just fine. As the camera scans the image, the LED lighting is alternating between on and off resulting in the banding your are seeing. Some AC powered LED strings are better than others (half wave vs full wave rectification. Full wave rectification generally will be better, but the best solution is to use LEDs that are powered from a real DC power source. That eliminates the LEDs flashing.
Your alternator has a voltage regulator in it which converts the AC to DC. If your LEDs start pulsing (visible to the naked eye), it means the regulator is starting to go or was a dud from the start.
The one in my truck was so bad when new that even the incandescent interior lights pulsed at idle, thank god for warranty as it was like an $800 part (can’t replace the regulator separate from the alternator these days).
Most LED lights (other than cheap xmas lights) are full wave rectified these days, but of course to keep costs down they don’t use the best components, so some cameras will still pick up a bit of flicker. The wavelength and angle of the light could simply be conflicting with the image sensor too.
I pulled apart an LED light bulb once and am amazed they don’t burn out within a few days, but I’ll give them credit, somehow they make it work (being an electrical engineer, I’m almost certain there’s a bit of magic involved based on what I saw). They pretty much rely on a piece of ceramic to keep the low rated/overloaded components cool.
It’s really obnoxious that even the luxury brands can’t use a decent PWM controller up at like 1khz or something. It’s really only noticeable when you look quickly in the rearview mirror but still seems like they could spend the extra couple bucks.
I can only imagine the nightmare the camera guys have to go through when filming commercials to try and get the right frame rate.
I lease and have seen this on several of my leases since 2015, through the lens of a camera only. Even straight from the dealer.
I didn’t realize we had AC (Alternating Current) in our cars but we do have alternators or used to. I have only tapped into 12vdc to add lights, gauges and radios.
I remember old tube TVs were difficult to sync when filming for TV.
I thought I remember that florescent lights also cycle on and off many times a second. Seems those can give you headaches. Incandescent was recommended for reading.
It’s amazing what technology you forget and move on.
Yeah that’s normal then due to the aforementioned PWM they all use, mostly to regulate the output and stay within federal rules. That’s also why most of the after market LED headlight bulbs are illegal and blinding.
Yep unless it is a battery powered car the only type you can generate from rotational motion is AC, then have to convert it to DC to run pretty much everything in the car.
Edison actually pushed for DC power into homes, that’s what his original grid ran, but it travelled far too short of a distance to be useful in most places, so Tesla won that battle (probably the only one he won).
There’s a lot of stuff these days that would benefit from homes running on DC, but back then it was mostly incandescent lightbulbs and heat which works equally fine on either one.
I know fairly all about AC/DC and Tesla/Edison but I guess I didn’t realize AC was being used to create DC in the car. I blindly believed a generator generated DC. I blindly overlooked that marvel and took it for granted. Thanks for pointing that out.
In a way it does since the AC to DC regulator is built into it. It generates AC then runs it through the regulator and the wires coming out are DC, so in a way I guess it is “making” DC but not really generating it.
We’ll see what comes of it. With so much solar (native DC) and Fuel Cells which put out DC also (I think it is eBay that runs their entire data centers off fuel cells now) maybe we’ll start seeing some DC hookups in houses. So much electricity is wasted on the conversion, especially in a house with solar panels, first DC to AC, then most of the electronics in the house are just converting the AC back to DC.
Very true. I have multiple 600w power banks I charge with AC. If I use an AC item, it converts the DC to AC. I am trying to get all DC appliances for emergency use so atleast I don’t lose anything in the conversion. I guess I could charge the power banks with my solar panels or my car’s outlet. USB helps out a lot being able to give up the wall adapter for DC to DC use.
It’s like heating up tea to later put ice into it.
Nope. Prior to the early 1960s, cars used generators that directly made DC power. They changed to using alternators and rectifying that into DC because they worked better - especially at low speed. No problem building a DC generator. It will be larger and cost more than an equivalent 3 phase alternator.
True but back then they needed a couple amps. A modern car would need one half the size of the engine. In reality, I still consider it AC in a way, while it isn’t a sine wave, the polarity is constantly changing and they need a second stage to align it and make it useful. The current flows back and forth in the generator, which is still sort of “Alternating Current”.
Technically any DC motor can used in reverse to generate DC current, it just isn’t very efficient and would need to be pretty large.
I’m a retired camera guy - pro gear is no problem because we can adjust settings but my issue here is a cheap wyze surveillance camera with no settings. (no shutter speed or lux adjustment). I’m sending the light back and maybe looking for incandescent-type light.
Yeah the Wyze cams have no adjustments like that, they can set it in firmware but we can’t do anything.
I have several cams in areas with standard LED light bulbs and have not had any issues with them affecting the cam. Those bulbs are full wave rectified so you may just need to look for an LED bulb or fixture that has better “smoothing” in the AC to DC rectification.
