Ordered two or the official PP cameras.
Three different brands of LED panel lights (Honeywell, Walmart, and Amazon generic import) in the top of my customized 440 enclosure produce a rolling shutter effect.
I doubt there is an easy option to fiddle with the USB camera drivers to alter the shutter speed on the cameras as a workaround.
Has anyone else run across this and have you found LED panel lights that do work?.
Standard hanging LED shop light also added to list of light sources that cause rolling shutter when directly above the cabinet. Not as much when they are indirect light (hanging from the ceiling). Not as bad as the work lights but still there and annoying.
Some inexpensive videography lights seem to work but are 100% plastic and not suitable to mount to the cabinet as I had with the LED work lights which are aluminum and glass lens.
20 Watt LED powered off AC is also a fail. I don’t know what’s the special sauce in those MX enclosure LEDs.
The videography lights, or something similar, are going to be your best bet. They have built in circuitry to buffer the AC sine wave and prevent the 60hz flicker that is causing your rolling shutter effect. If it were me, I’d probably just run them until the coolant or chips causes enough damage to warrant replacing them. Or, if that happens too quickly, build an enclosure to keep them in.
The videography lights appear to be DC and use a “wall wart” adapter. I think that may be the substantial clue as to why they work as opposed to them being videography lights.
They would not last but a few days of continuous use unless completely shielded both on the light and the backside in this environment. That is more fabrication work than I want to do with way too many other projects. I would rather order and plug in something that is tough enough which doesn’t have the video issue. One last attempt incoming and if it doesn’t work, I guess I’m going to have to pony up for a set of the official MX lights.
FWIW, I have the official enclosure on my 1100mx and while I don’t have any issues with video shot at normal speed, slow motion videos cycle between bright and dim so there’s still some flickering happening, or at least dimming.
Essentially, you are correct that the wall wart is the solution but the truth is that all LED’s are DC at the discrete element level. The difference is in how they’re driven. Arguably, an LED can be driven with a direct AC feed depending on the specifics of the LED and the incoming voltage, it would just be operating at less than a 50% duty cycle (half the sine wave is in the right direction but part of that half is at too low of a voltage to power the LED). Feeding power at 60Hz directly into an LED would result in a 30Hz flicker (roughly). When you consider that 30 frames per second (30Hz) is about the minimum you need to generate “smooth” video, a 30Hz flicker would be more or less impercetible to the human eye but would certainly show up on a camera that is likely also capturing at 30fps.
To eliminate the flicker you need to continue to provide power during the negative half of the sine wave as well as the region of zero/near zero voltage. This is done by storing a bit of charge in a capacitor and releasing it when needed. You can reduce the size of the capacitor by recitifying the incoming AC so that both halves of the wave are flowing the same way. Then all you need to do is buffer that small region of near zero voltage. The wall wart certainly does the first part of that, and depending on the quality of it, may also provide that additional buffer. However, many of them are known as switching power supplies which will introduce their own noise to the output power which can still cause flickering. Linear power supplies are frequently larger, more expensive, and less efficient, but they provide much cleaner power for critical applications.
Thanks for the very thorough explanation! I am not an EE but certainly know which is the hot end of a soldering iron and how to use a breadboard and suspected the marginal power supply design was part of the issue…
This is what I ended up ordering and the PP cameras are no longer picking up a rolling shutter effect in case someone else is looking for lights to fit a machine that didn’t come with them.
These run off 12-60 VDC (or AC, according to specs, but not line voltage) and I was able to run them off the existing DC power supply in the 440 cabinet but caveat emptor to anyone else in terms of how much load there is on that power supply and if can handle the extra amperage from the two of them. I haven’t run a job with the lights on yet. My 440 has the PDB and ATC and there was only one open set of terminals for a new accessory.
That’s interesting info on the slow motion issue, which I would understand to be related to the video being at a frame rate of >30FPS (I want to say it is 120FPS on my iPhone). These lights seem to have this issue but it isn’t as bad at high frame rates as the rolling shutter was for regular frame rates. The “lab grade” variable voltage and amperage power supply I have didn’t eliminate the high frame rate artifact. In any event, I would have to use mist instead of flood or have to figure out an air nozzle to keep the windows clear as I’m not sticking my phone inside a machine cabinet, even in an armored case. Maybe a GoPro that supports slow-mo.