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WIGGLING 'LITE' IN GUEST MODE

LED Light Strips and Noise
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author LED Light Strips and Noise
Eric the Red
Good morning my fellow wigglers - wanted to throw a question out into the world for those that have far more knowledge than me.

I am in the midst of finishing up building a big asscase for my modular DIY project, and I want to add some pizzazz to it in the form of LED light strips.

I’m using the DotCom QPS-1 and QPS-3 (multiple cases, multiple power supplies)..

For the LEDs: https://www.taydaelectronics.com/5m-1-reel-5050-300-led-rgb-felxible-w aterproof-light-strip.html just a basic light strip off of Tayda

Power: https://www.amazon.com/gp/product/B015PXUHYA/ref=oh_aui_detailpage_o01 _s00?ie=UTF8&psc=1

My case is 11” deep, 16u in height. Power supply (QPS-1 or 3) will be placed on the bottom middle.

Is there a best spot to power the light strips from? Will this cause unnecessary noise? Is this just baseless paranoia? Will the neighbors think I have a discotheque in my basement?

Thanks in advance friends.

-Eric
ersatzplanet
If you power the LEDs with a switching PS you are basically making one large broadcast antenna out of that LED strip. I would give it a try and see if your gear is sensitive to the frequency of the switcher in that supply. Be prepared to go linear though.
cretaceousear
I'm sure I'd read that a strip of this size can need a good deal more power when set to "white". hmmm.....
Why not go addressable for moven blinken lighten ?
https://www.adafruit.com/product/1138 nanners
Eric the Red
Thanks guys!
Rex Coil 7
Doesn't LED induced noise also have something to do with how many there are and how fast they are blinking?

I think I just read something last night about it not being a problem as long as the LEDs draw the same amount of power whether they are on or off ... which obviously creates a set of engineering issues that would require addressing. I still can't work out how the heck you'd go about doing that!

seriously, i just don't get it hmmm.....
Rex Coil 7
(from Eric's opening post) .....

Eric the Red wrote:
....I’m using the DotCom QPS-1 and QPS-3 (multiple cases, multiple power supplies)..

-Eric


ersatzplanet wrote:
If you power the LEDs with a switching PS you are basically making one large broadcast antenna out of that LED strip. I would give it a try and see if your gear is sensitive to the frequency of the switcher in that supply. Be prepared to go linear though.


eek!

*ersatzplanet ..... Looks like ya missed something there, chief. He's got that covered. razz Mr. Green

Dot Com QPS1 and QPS3 PSUs are linear ...


QPS1 .... https://synthesizers.com/qps1.html

QPS3 .... https://synthesizers.com/qps3.html

thumbs up
Geo747
Quote:
Power: https://www.amazon.com/gp/product/B015PXUHYA/ref=oh_aui_detailpage_o01 _s00?ie=UTF8&psc=1



Eric said that the Modular is powered by the QPS1 and QPS3 but linked a wall wart from amazon to power the light strip, which is switching and so therefore potentially vulnerable to the issues ersatzplanet talked about.

Despite that i think its fairly unlikely there will be any problems using the led strip if eric wires them directly to the power supply as it will just be DC going from the wall wart through the leds. If you use one of those RGB LED controllers (which I assume eric will as otherwise you can only have each colour either on or off) then the controller will very likely be using pwm to control the LEDs but I've never experienced intereference or anything from these LED strips so its probably fine. If there was to be problems it would likely be from proximity of the power supply or the pwm controller to the modular not the LED strip. Hope that helps a bit.

George
Rex Coil 7
Geo747 wrote:
Quote:
Power: https://www.amazon.com/gp/product/B015PXUHYA/ref=oh_aui_detailpage_o01 _s00?ie=UTF8&psc=1


Eric said that the Modular is powered by the QPS1 and QPS3 but linked a wall wart from amazon to power the light strip, which is switching and so therefore potentially vulnerable to the issues ersatzplanet talked about.
HAA! Well then, I suppose I should read a bit before I open my pie hole! meh

d'oh!

thumbs up
ersatzplanet
Geo747 wrote:
Quote:
Power: https://www.amazon.com/gp/product/B015PXUHYA/ref=oh_aui_detailpage_o01 _s00?ie=UTF8&psc=1



Eric said that the Modular is powered by the QPS1 and QPS3 but linked a wall wart from amazon to power the light strip, which is switching and so therefore potentially vulnerable to the issues ersatzplanet talked about.

Thank you, I was about to post that out.
Geo747 wrote:

Despite that i think its fairly unlikely there will be any problems using the led strip if eric wires them directly to the power supply as it will just be DC going from the wall wart through the leds. If you use one of those RGB LED controllers (which I assume eric will as otherwise you can only have each colour either on or off) then the controller will very likely be using pwm to control the LEDs but I've never experienced intereference or anything from these LED strips so its probably fine. If there was to be problems it would likely be from proximity of the power supply or the pwm controller to the modular not the LED strip. Hope that helps a bit.

George


The problem is that many switching power supplies, especially smaller ones like the one shown, often have little filtering on their outputs. This is because of course they are seldom required to with the uses they are typically put in. All switching power supplies end up putting out DC but many don't do much filtering. There are ones that do a great job, like the Doepfer PS3, which actually follows the switcher output with linear regulators, which is the best way to do it. Hook your typical small switcher output to a scope and you will see what I mean. There looks like there is not a ton of room in that wall wart switcher for decent sized caps for filtering, but of course since I don't have one here to look at, I may be totally wrong though.
Addled
Added in error
ersatzplanet
Since this thread was started, Doepfer decided to get in on the LED strip action and has a module coming out in February for doing this -



It can be seen around the 2:00 mark in this video -

[/video]
sduck
I put a cheapo rgb led strip in my new modular case -



It's just a strip from home depot. Has a nice little remote controller. I tried running the thing off the euro power, but that didn't work, so now the transformer/controller thing sits on a shelf below the cabinet - the attached wire is long enough. I haven't noticed any noise from it yet.
fuzzbass
sduck wrote:
I put a cheapo rgb led strip in my new modular case -



It might be bright and twinkly, but sduck has gone over to the dark side - EURO! Feel the rage coursing through your ribbon connectors. Just try twisting the knobs on those 2U modules. Now where is my Maths - oh here it is under this hairball. razz
chachi
sduck wrote:
I tried running the thing off the euro power, but that didn't work,


bummer. i was going to try this, just use a euro header and plug in. what didn’t work about it? just never came on?
honeyb
Blinky lights good.
ersatzplanet
chachi wrote:
sduck wrote:
I tried running the thing off the euro power, but that didn't work,


bummer. i was going to try this, just use a euro header and plug in. what didn’t work about it? just never came on?


I noticed that the Doepfer module has an external supply input jack on it. Doepfer doesn't say it is needed, it is just an option. They do mention the current draw of the LED strips they use at being ~800mA @+12V which is sufficient to impact many supplies. I would check your supplies.
sduck
chachi wrote:
sduck wrote:
I tried running the thing off the euro power, but that didn't work,


bummer. i was going to try this, just use a euro header and plug in. what didn’t work about it? just never came on?


It actually worked fine for a while, but I think running the leds and the controller hardware overtaxed one of the capacitors, and it started blowing fuses. There may be a better way to do the hack job I did on the power - someone with more patience than me might get it right. I probably just didn't find the right place to tap in the 12v. If you're ok with just some simple on-off type switching it would certainly work fine, I just wanted the color cycling effects from the controller. I had this strip leftover from another project I was doing that weekend - making little battery powered light strips to turn cello and violin bows into pseudo light sabers - if you can run these things off of little disk batteries, you can certainly run them off 12v.

In this video on instagram you can see the light strip running off the euro 12v - it didn't last long after this - https://www.instagram.com/p/Btw9vMRl7NW
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