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Topic: Impedance matching 4ft of 20awg wire (Read 4032 times) previous topic - next topic

Qdeathstar

#30
Apr 17, 2016, 04:23 pm Last Edit: Apr 17, 2016, 04:29 pm by Qdeathstar
Video is scanned from the top down so if at the time of the flash the scan is half way down that frame does not 'see, it, the next frame picks it up however.

This gives the perceived effect of movement where there is none.

A similar faster effect occurs in the horizontal scan direction.

Stop motion, (frame by frame) is needed to be sure, that event is just too fast.


Does your power supply allow the output to be floating, that is not connected or referenced to mains earth.

Lab supplies normally do this but i am not sure about server PSU's

EDIT

Trying to video with the camera on its side may give more insight.
hmm. interesting. I will try to record again later tonight. I recorded at 60fps, and the blink seems to take about half a second to propogate. Maybe I'll try recording at 120fps. And sideways.


I am not sure about the power supply.

Here is the link:
http://www.amazon.com/HP-1200W-Power-Supply-500172-B21/dp/B007YW9OJU?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_search_detailpage
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Boardburner2

#31
Apr 17, 2016, 04:33 pm Last Edit: Apr 17, 2016, 04:40 pm by Boardburner2
hmm. interesting. I will try to record again later tonight. I recorded at 60fps, and the blink seems to take about half a second to propogate.


My suspicion is that whole blink lasts only a few milliseconds.

I suspect that psu is mains grounded.

Do you have a mains isolating transformer you can borrow.
Big yellow thing often found on building sites.

Boardburner2

as an afterthought , do you know what your electric utility supply type is ?

TN-S  ?  TN-C ?  , something else

MarkT

Looks like your setup is very much an antenna, you will need to break it up into shorter sections separately
driven to avoid susceptibility to airborne transients. Possible some high-speed logic opto couplers (not
ordinary ones, way too slow) inbetween separate sections to pass on the signals?

Am I right in assuming the strips are not near any other metal parts of the building?

Basically you are hoping to run effectively a single unshielded 5V logic circuit spread over 50m up on
a roof, which is pretty crazy - no EE would ever imagine that could work reliably outside of a faraday cage
chamber.  Its going to behave like an ad-hoc short wave antenna and pick up who knows what.
[ I DO NOT respond to personal messages, I WILL delete them unread, use the forum please ]

Qdeathstar

as an afterthought , do you know what your electric utility supply type is ?

TN-S  ?  TN-C ?  , something else
Ehhh.. It's 120/240 single phase. Dominion Power is the power company. How would I find that information, and how would I go about getting it.


Mark the strips are ran inside of aluminum Chanel that is glued with double sided 3m tape to metal flashing.

A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Qdeathstar

My suspicion is that whole blink lasts only a few milliseconds.

I suspect that psu is mains grounded.

Do you have a mains isolating transformer you can borrow.
Big yellow thing often found on building sites.
I know it's not recommended but if I cut the ground lead off the transformer would that do anything to isolate the ground? I have the transformer plugged into a power conditioner.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Boardburner2

chamber.  Its going to behave like an ad-hoc short wave antenna and pick up who knows what.
The flash on the video implies high power.

Unless someone is playing with nukes and i would think someone would have noticed, i suspect some sort of earth fault.

Not sure what though.

Qdeathstar

#37
Apr 18, 2016, 12:04 am Last Edit: Apr 18, 2016, 12:05 am by Qdeathstar
What can I try? I'm going to give the tvs diodes a try first, but always like more options
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Qdeathstar

it seems you were right about the direction issue, Boardburner.  I am video taping horizontal, and the blink happend simultaneously. 

I had I zoomed in the corner expecting a certain result but did not get it. I am now zooming out to see how far the blink goes. I'll post an updated video.


the thing I shiuld mention again, is that I have it on only 10 percent of full brightness during the video, and when the blink happens, it seems like it goes to full brightness, but not brighter than that. Ofc, it happens so fast it's hard to be certain.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Boardburner2

Basically you are hoping to run effectively a single unshielded 5V logic circuit spread over 50m up on

I am starting to think this may be down to ground bounce type effect somewhere.

Either in the strip or psu.

Boardburner2

I have the transformer plugged into a power conditioner.
What transformer ?, you have not mentioned this before.

Qdeathstar

sorry, used transformer/psu interchangeably. I have it mains >> conditioner >> psu
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Boardburner2

#42
Apr 18, 2016, 09:24 pm Last Edit: Apr 18, 2016, 09:29 pm by Boardburner2
I know it's not recommended but if I cut the ground lead off the transformer would that do anything to isolate the ground?
If you have a TN-C electrical supply then earth and neutral are connected together anyway.

Lot of power in that flash, changing something could blow your strip.

Only solution i can think of is to use a CTE isolating transformer and derive a local earth.

For a test though you could try a battery and only illuminate a few pixels.
Dont forget to isolate the arduino as well.

Looking around i see that some of those supplies can be made to float by cutting links inside, i dont know your abilities though , those supplies can be lethal.

Qdeathstar

Ground and neutral are tied together at the panel by two ground rods and cold water pipe.


I head you mention an isolation transformer earlier... Something like this to try?

http://www.amazon.com/Precision-1604A-Single-Isolation-Transformer/dp/B000LDLF3M/ref=sr_1_3?ie=UTF8&qid=1461008046&sr=8-3&keywords=isolation+transformer




Also,I'm going to run it at full brightness today and see if I still get the blink, as I hadn't done that yet I just realized.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.


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