# DIY led build--need some help :(



## fietsenrex (Oct 8, 2014)

so as you might have noticed, I've copied the build of fisure and made it sort of my own.

everything seems to work except for one thing.. some LEDs don't light up..
I've build 2 fixture's both have 24 tri-star LEDs (stevesleds)
-24 ultra violet
-24 red
-12 royal blue
-12 cool blue
each set of red and violet have thier own driver, (24 leds on 1 LDD-700)
the blue are looped and also have 24 LEDs on one LDD-700.
the system runs on a meanwell LRS-350-48 power supply

now here come's the strange thing..
in fixture 1 violet 6-19 doesn't light up and in fixture 2 blue 6-12 doesn't work.
swapping drivers doesn't make an impact.
they all tested OK and function when tested.

I'm a bit confused on what to do now..
I've got a FLUKE 289 at hand but am not that familiar with the settings.
so if there is anything I can messure with the fluke to determine the problem I would really appriciate it.

kind regards


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## jeffkrol (Jun 5, 2013)

H-violets are listed at 3.7V at 800mA... so guesstimating a V(f) of 3.6 x 24= 86.4 V ..
Your meanwell minus ldd losses is only capable of about 45V per string..

so your lucky any light up at all..or you need to explain your wiring better..
Only way to get all 24 is 12x 2 series/parallel array w/ each series string seeing 700/2= 350mA each

(3.5 x12 = 42V plus 3v for LDD ps needs to be 45v or better)


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## fietsenrex (Oct 8, 2014)

No you're correct they are wired in series.
But the strange thing is that only fixture 1 had this issue and not 2.

Anyhow I'll rewire both fixtures so the violet has 2x12 instead of 1x24 strings. 

Thanks for the help  bit odd that I figured 24 violets on 1 LDD would work..


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## fietsenrex (Oct 8, 2014)

Well, they run brighter I think but it didn't solve the problem..


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## fietsenrex (Oct 8, 2014)

The 2 fixtures
Fixture 1 is on the right and 2 is on the left, its really hard to see what works and what doesn't but the problem remains the same unfortunetly


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## Sharon_hazan (May 5, 2016)

what about full spectrum led?


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## Maryland Guppy (Dec 6, 2014)

fietsenrex said:


> I've build 2 fixture's both have 24 tri-star LEDs (stevesleds)
> -24 ultra violet
> -24 red
> -12 royal blue
> ...


In post #4, 1st pic, what is the LED that is not lit up?
LED in the center? It does not look like a tri-star?
Looks like a higher voltage COB type LED.

Do you have a sketch of your wiring?

Part count is 72 LED's, but 2 fixtures with 24ea = 48?
How many LDD's do you have?


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## fietsenrex (Oct 8, 2014)

In the middle row are bridgelux, they run on thier own LDD-1000 and are working fine 

But 7 violet don't light up in fixture 1 and 3 blue in fixture 2 the rest is working fine.

The colored are powered by 6 LDD-700 drivers
1 for red in fixture 1
1 for violet in fixture 1
1 for red in fixture 2
1 for violet in fixture 1
1 for Royal blue in both fixtures 
1 for cool blue in both fixtures


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## jeffkrol (Jun 5, 2013)

Well it wasn't the LDD but the power supply limits..
Well both really... 

LDD is really a current controlled buck voltage regulator..Which in this case will out max voltage but due to it being low will never output its rated current..
Reds are the same but your output is better (go guarantee it hits full of the LDD though) because red's V(f) is like 2.3-ish V.. 55V 

This is for a constant voltage array but it will get you an idea of possible and impossible strings..
http://led.linear1.org/led.wiz

Anyways, if you have one that works and another that doesn't .. same exact config, you need to start looking at little things. Like if any of the solder points are "bridging" to the heat sink.
Using a VOM set to the lowest Ohms channel, you can put pos to neg across a single diode and it should dimly light.
Then pos to pad neg to heat sink.. reverse and repeat neg to pad pos to heat sink ..



Redo any that light if you touch pad and heat sink w/ the correct polarity of course.

just for reference:









Blues have the same issue probably.
Part of it could be lot variations of v(f)


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## fietsenrex (Oct 8, 2014)

Sharon_hazan said:


> what about full spectrum led?


What do you exactly mean?


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## fietsenrex (Oct 8, 2014)

Thanks Jeff will try that, but if that is the case how do I fix it?


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## Sharon_hazan (May 5, 2016)

fietsenrex said:


> What do you exactly mean?












380~840nm in one package

https://www.youtube.com/watch?v=S0gB8BL4IFc&ab_channel=AlenAxP


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## fietsenrex (Oct 8, 2014)

Sharon_hazan said:


> fietsenrex said:
> 
> 
> > What do you exactly mean?
> ...


I see, but I don't use those


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Thanks Jeff will try that, but if that is the case how do I fix it?


Just de-solder and re-solder.. Usually just a small edge "bit" that overhangs the insulating coating on the top of the star..
Bridges the pad to the star "base"..

FYI:
Remember that when you run 2 series strings in parallel they will "split" the amps.. BUT.. if one goes out (say wire breaks) all the "split" current will run to 
the remaining string.. 
so 2 w/ a 700mA LDD will each be at 350mA until one goes "off line', then the full 700mA will be driving the remaining string..
Many people fuse each at, in this case, say .5A so it will blow instead of driving the one at 700mA


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## fietsenrex (Oct 8, 2014)

Thank you very much, it was indeed the case that it was bridged to the heatsink.
I'm going to resolder it tomorrow and retest it

But the leds should be fine at 700ma, didn't think of fuses maybe I'll fit them anyway


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## Sharon_hazan (May 5, 2016)

ohh sorry i thought you searching for led...


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## fietsenrex (Oct 8, 2014)

Thanks again Jeff, all the leds are working now and are now running on 350, I'll order fuses tomorrow and fit them


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## jeffkrol (Jun 5, 2013)

Great.. There are more "elegant" modifications to parallel strings than fuses but "mostly" unnecessary..

http://www.st.com/content/ccc/resou...df/jcr:content/translations/en.CD00145612.pdf

Easier just to buy another set of LDD's..


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## fietsenrex (Oct 8, 2014)

yeah buying them is easy, retro fitting everything would be a complete nightmare 
I'll just go with the fuses, it doesn't have to be elegant, it has to be functional in my opinion 

I'm more than happy that everything is working properly now


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## fietsenrex (Oct 8, 2014)

Well I've run into the next problem..
I've 3 power supply's, I tied all the "-" together and to the controller "-".
The power supply first in line is working fine and the leds dim.
But the second doesn't dim.. 3rd is not connected becuase I was trying to troubleshoot..

Basically the Vero don't dim, they are supplied by LDD-1000h.
Each Vero has its own LDD

All the colored leds are working fine









Edit: might be the problem that I'm trying to run 12 LDD's from 1 PWM signal..
I've come to think that the signal is not powerfull enough to be fed to 6 or more LDD's


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## Sharon_hazan (May 5, 2016)

fietsenrex said:


> Well I've run into the next problem..
> I've 3 power supply's, I tied all the "-" together and to the controller "-".
> The power supply first in line is working fine and the leds dim.
> But the second doesn't dim.. 3rd is not connected becuase I was trying to troubleshoot..
> ...


you can put on each led input a transistor that connected to the pwm from the controller 

http://i.stack.imgur.com/s0YCG.jpg


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Well I've run into the next problem..
> I've 3 power supply's, I tied all the "-" together and to the controller "-".
> The power supply first in line is working fine and the leds dim.
> But the second doesn't dim.. 3rd is not connected becuase I was trying to troubleshoot..
> ...


Well easy enough to test. just hook one up at a time..
The LDD is reported to just use micro-amps and as such you should have plenty of power w/ say 40mA for 12 LDD's.
Think the coralux storm has a lower limit..


> Max PWM current per pin::
> 40mA (Storm),
> 10mA (Storm X





> At 100% duty cycle, the LDD pulls *7.7µA* on its dimming circuit. At 0% duty cycle, the LDD pulls *53µA* on its dimming circuit.
> 
> Since they dim to 0, the 53µA must be used.
> 
> ...


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## fietsenrex (Oct 8, 2014)

Sharon_hazan said:


> you can put on each led input a transistor that connected to the pwm from the controller
> 
> http://i.stack.imgur.com/s0YCG.jpg


that was sort of my option to go if the PWM signal was not powerfull enough, just beef it up with a 5V power supply and a transistor



jeffkrol said:


> Well easy enough to test. just hook one up at a time..
> The LDD is reported to just use micro-amps and as such you should have plenty of power w/ say 40mA for 12 LDD's.
> Think the coralux storm has a lower limit..


that would be an option, only downside is I've soldered all the LDD in place.
testing them 1 by 1 would mean I have to dangle above my aquarium holding a soldering iron.. not impossible but also not very desirable 

I'm going to try to make a diagram of all my wiring to explain how I connected everything


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## fietsenrex (Oct 8, 2014)

got the diagram drawn, hopefully this clears it up a bit


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## jeffkrol (Jun 5, 2013)

My only guess at this point is the "pin" is not doing the PWM out..
Can you switch one of the colored Aduino pins to the Vero LDD's?..
http://forum.arduino.cc/index.php?topic=28493.0


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## fietsenrex (Oct 8, 2014)

Tried it and fried a resistor.. So at least I know why it wasn't dimming, now got to figure out why the resistor is burned out..
Resistor was 220 ohm SMD style one.


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Tried it and fried a resistor.. So at least I know why it wasn't dimming, now got to figure out why the resistor is burned out..


Why do you have resistors??
at 40MA there is no need to throttle the current.
Normally the only reisitor needed is a "pull down" to ground in the event of a controller failure. Will shut the light off..
12 resistors in line to the LDD's on the vero line can possibly quench enough mA to float the PWM output.. (???) 









Possible hints:
http://www.ultimatereef.net/forums/showthread.php?726477-New-tank-New-LED-Build/page2


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## fietsenrex (Oct 8, 2014)

The controller came with a resistor on each channel to protect the arduino 
So bypassing the resistor could solve the problem if all the wiring checks out?


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> The controller came with a resistor on each channel to protect the arduino
> So bypassing the resistor could solve the problem if all the wiring checks out?


Can't guarantee it but it makes sense to me.. I've seen many build these w/ no "safety" resistor "in-line"..
Now a 10k resistor from PWM to ground to shut off the lights in a controller failure is another story. 
Mostly the SW people use it so as to not fry their corals.
Many LDD "boards" have one attached.. Preferred if they had it "jumperable" so as to eliminate it to troubleshoot..

Why you blew a resistor is a curiosity though...


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## fietsenrex (Oct 8, 2014)

I think 12 LDD's might just pull enough current that the resistor gave in.
But it doesn't make sense since the LDD only uses micro currents

I think I try a "normal" 4.7k resistor since I do want some safety.

Wiring checks out no shorts found..
Every connection is 160+ mega ohm
Between "-" and "dim" and between "+" and "dim"


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> I think 12 LDD's might just pull enough current that the resistor gave in.
> But it doesn't make sense since the LDD only uses micro currents
> 
> I think I try a "normal" 4.7k resistor since I do want some safety.
> ...


Well if you are going to remove and replace, just leave them out for a test..After that add resistors if so deemed..

Pretty sure they are unnecessary unless you "direct drive" LED's off the pin...
Just some old background..
http://www.reefcentral.com/forums/showthread.php?t=2453169&page=4


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## fietsenrex (Oct 8, 2014)

Well not replace just by-pass the broken ones


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Well not replace just by-pass the broken ones


aren't there more PWM pins? You could just split the Vero channel into 2



> I think I try a "normal" 4.7k resistor since I do want some safety.


Thought you were going to replace them?


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## fietsenrex (Oct 8, 2014)

jeffkrol said:


> aren't there more PWM pins? You could just split the Vero channel into 2


Yes, got 16 in total.
Feel kinda dump that I didn't think of that, but I wanted to control all the white with 1 slider



> Thought you were going to replace them?


Only the burned out ones, I'm not going to retro-fit something which is working properly


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Only the burned out ones, I'm not going to retro-fit something which is working properly


What fun is that.. I retrofit working products a lot.. 









Of course I didn't remove the MOSFET..


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## fietsenrex (Oct 8, 2014)

Yes I've seen your thread on the tc420 
Real Nice work on making a semi usefull product on a real usefull product


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Yes I've seen your thread on the tc420
> Real Nice work on making a semi usefull product on a real usefull product


Yea, still chugging along on the 40b..

I shouldn't bug you about the resistors. Still have no idea why you'd burn one out..
Whole point is to limit the current drain which is minuscule w/ a dozen LDD's.. 









Arduino - Before You Buy - ShareTechnote
Beyond my pay grade now.. 

found a different quote regarding the LDD current draw on the PWM circuit:


> t's quoted in the LDD data sheets (LDD-H and LDD-L) at 1mA max at quiesce, so again, should be more than fine


total drain could approach 12mA..for 12.. 
http://www.reefcentral.com/forums/showthread.php?t=2482207
or this:
http://www.reefcentral.com/forums/showpost.php?p=21145416&postcount=738
Seems they may just round up the .053mA..to one??????


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## fietsenrex (Oct 8, 2014)

Only thing I can think of would be wire losses and maybe some bad soldering contacts..

But none of the contacts have any cold welds and everywhere the solder has flown fully through all the wire tiers.
There is nowhere any bare copper left


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## fietsenrex (Oct 8, 2014)

jeffkrol said:


> found a different quote regarding the LDD current draw on the PWM circuit:
> 
> 
> > t's quoted in the LDD data sheets (LDD-H and LDD-L) at 1mA max at quiesce, so again, should be more than fine
> ...


Adds up to 0,636mA 
Quete odd that it would blow a resistor
But maybe the resistor is only suited for LDD's 1 on each channel


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## fietsenrex (Oct 8, 2014)

Got 2 channels retrofitted and working again 
Found out that 1 of the 2 fixtures is causing all the trouble so I have to recheck everything again and maybe just resolder it all to be sure


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## fietsenrex (Oct 8, 2014)

Turned out to be a wire break.. 
Got it sorted now thanks for the help


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## fietsenrex (Oct 8, 2014)

Crap, it wasn't fixed..
Somehow the LDD's burned up.. 
No PWM works on the affected driver box..
This morning it all worked properly, when I got home this evening the LDD's were to hot to touch and don't dim anymore....
Pretty sad right now, next week I think I'm going to order new LDD's and rebuild the whole driver box since the other one is working fine and don't run hot just slightly increased compared to ambient temperature


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## fietsenrex (Oct 8, 2014)

Maybe worth mentioning, but the PWM signals run through a cat5 unshielded utp wire guage is awg26
The wiring for the power is all awg18 don't know for sure.
Also the ground wire from the ps to the controller is awg18
Would the awg26 have caused issues due to radiation or something?


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## jeffkrol (Jun 5, 2013)

Meanwell LDD driver: for those who want to dim to 0 using Arduino - Page 78 - Reef Central Online Community

Need better pictures of entire setup.. LDD's generally never get hot..


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## fietsenrex (Oct 8, 2014)

Power and PWM come up in the canopy on the right side.
The run on the side of the canopy to the center where the driver boxes are located

And some pictures of the internal wiring of the affected driver box.
All the power lines and PWM run in parallel in the box
For the leds I've used D-sub 9 connectors and awg18 wiring
As said before each Vero has its own LDD

Btw, the PWM wiring is not waterproofed yet since the problems remain to bug me


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## Nordic (Nov 11, 2003)

Little durability tip, a little hotgun glue on the board where external wires connect to it, stops twisting, frays and shorts.


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## jeffkrol (Jun 5, 2013)

gut tells me you should just scrap the driver boards for commercial units.. 
LDD-H-4 Driver Board - Rapid LED


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## Maryland Guppy (Dec 6, 2014)

jeffkrol said:


> gut tells me you should just scrap the driver boards for commercial units..
> LDD-H-4 Driver Board - Rapid LED


I second this idea!

I also have never had an LDD driver even really get warm?
In a non-vented enclosure they run 5-10 degrees above room temp.


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## fietsenrex (Oct 8, 2014)

LDD-6 Driver Board | CORALUX

something like the board above seems to meet my needs better since I've got a 6 channel setup, would this also work?
all the other driver run cool, the temperature inside the box is slightly higher than ambient temperature.

first I had opted for the boards made by O2 but he suddenly didn't reply anymore so I went ahead and build my own system, which turned out not so great as you all can read..

1 more question, would the driver boards mentioned above be fine in a ventilated canopy? or do I need to fabricate an enclosure for them?


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> LDD-6 Driver Board | CORALUX
> 
> something like the board above seems to meet my needs better since I've got a 6 channel setup, would this also work?
> all the other driver run cool, the temperature inside the box is slightly higher than ambient temperature.
> ...


First I "personally" do not like the pull down resistors permanently attached to the board which is why I listed the other one..
Pet peeve.

I'd probably "enclose" them in a canopy but it would depend a lot on placement. Many put the bard on top of the heatsink so little direct splash..


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## fietsenrex (Oct 8, 2014)

Went for the 4-channel you mentioned
As you mentioned before that the standard fitted resistor would make trouble shooting somewhat difficult, it would be wise to go with the ones without them.

Now I'll be waiting for the boards to arrive and retrofit everything and build something as a splashguard


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## fietsenrex (Oct 8, 2014)

got the boards delivered last week.
already installed 1 but I notice a high pitch "buzz" coming of the board.
this board contains brand new LDD-1000's 

is this "noise" normal?
I didn't notice it before, it's only when the lights are dimmed to about 20-30% and it's very soft almost at the end of my hearing.


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## Arun. (Apr 30, 2016)

fietsenrex said:


> got the boards delivered last week.
> already installed 1 but I notice a high pitch "buzz" coming of the board.
> this board contains brand new LDD-1000's
> 
> ...


Try changing the caps to electrolytic ones http://www.plantedtank.net/forums/20-diy/731121-led-build-526-watts-vero-leds-colored-leds-%2Aupdated-2015-05-25%2A.html check last paragraph of 1st post


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## fietsenrex (Oct 8, 2014)

got the meanwell LDD's not the one's build by O2, so that is not an option unfortunately..


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## Arun. (Apr 30, 2016)

I am not an expert, but you can try increasing PWM frequency. I am running my drivers at 2kHz on DIY driver based on PT4115 without any noise.


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## jeffkrol (Jun 5, 2013)

Arun. said:


> I am not an expert, but you can try increasing PWM frequency. I am running my drivers at 2kHz on DIY driver based on PT4115 without any noise.


Spec for an LDD-H is 100Hz-1kHz
"Stock" Aduino pwm frequency is usually noiseless AFAICT..


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## fietsenrex (Oct 8, 2014)

My fluke says 1.7 KHz..
Between PWM and -

Strange thing is that its only on 1 or 2 of the LDD-1000, the 700 are fine


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> My fluke says 1.7 KHz..
> Between PWM and -
> 
> Strange thing is that its only on 1 or 2 of the LDD-1000, the 700 are fine





> Writes an analog value (PWM wave) to a pin. Can be used to light a LED at varying brightnesses or drive a motor at various speeds. After a call to *analogWrite()*, the pin will generate a steady square wave of the specified duty cycle until the next call to *analogWrite()* (or a call to *digitalRead()* or *digitalWrite()* on the same pin). The frequency of the PWM signal on most pins is approximately 490 Hz. On the Uno and similar boards, pins 5 and 6 have a frequency of approximately 980 Hz. Pins 3 and 11 on the Leonardo also run at 980 Hz.


https://www.arduino.cc/en/Reference/AnalogWrite
https://arduino-info.wikispaces.com/Arduino-PWM-Frequency


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## fietsenrex (Oct 8, 2014)

I'll have a look at that tomorrow








Just a quick pic of the fluke.

Btw can I just daisy chain 2 boards together with a Total of 6 drivers on them?
I've got them setup with 4 on one board and the other 2 on the other board


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## jeffkrol (Jun 5, 2013)

divide it by 1/2.. Why? 
Don't know but I assume it figures a full AC "wave".. which w/ DC PWM is not really relevent..????
Above my pay grade..
850Hz is at least in the "ballpark" of expected values..976-980 ish
Re-code it to 490 (default) which you can on all pins but D4 and D13
Again, WAY above my pay grade and only sharing "info"...



> If you use the default values set by the Arduino Diecimila's bootloader, these are your PWM frequencies:
> 
> Arduino Pins 5 and 6: 1kHz
> Arduino Pins 9, 10, 11, and 3: 500Hz


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## fietsenrex (Oct 8, 2014)

Think this makes more sense


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## jeffkrol (Jun 5, 2013)

Yep.. sure does.. so the hum is probably not the PWM frequency.. since "everyone" uses 490-ish.. 
as to your other question.. you can attach as many boards to one PS as it can handle..AFAICT.

for a more esoteric answer.. It could be that some do "buzz" but most people cannot hear it.. (different sensitivities)
Certainly has been reported before but not really common..



> Originally Posted by Yam View Post
> Does anybody also experience the buzzing from the LDD-1000H? If the PWM signal is anywhere between 5 - 95%, they start buzzing. At 100%, they are silent. Running 5x LDD-1000H w/ HRP600-36 powersupply on a test jig with a "dream chip" and an arduino.
> 
> I was hoping to only run them ~80% or so.
> ...


http://reefcentral.com/forums/showthread.php?t=2222702&page=47


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## fietsenrex (Oct 8, 2014)

I'm more concerned about the PWM.. 
Anyhow got the second set of boards with LDD 1000 up 
But the hum seems to be caused by the PWM 
I've one set running at 12% and one at 15%
And the one at 12% hums a bit more..

Although its not common, so am I


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## jeffkrol (Jun 5, 2013)

As suggested, you can play w/ the frequency a bit..Go to 980-ish on most pwm pins.
Or go to 700mA ones..


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## fietsenrex (Oct 8, 2014)

Will dig into the PWM frequency tomorrow
If the humming gets anoying I'll maybe swap them out for ldd700


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Will dig into the PWM frequency tomorrow
> If the humming gets annoying I'll maybe swap them out for ldd700


Just an unhelpful FYI..but there is a sound recording..

Drivers meanwell LDD....hum
More..
http://www.reefcentral.com/forums/showthread.php?t=2222702&highlight=ldd+drivers&page=114


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## Arun. (Apr 30, 2016)

You may try adding some extra leds on that noisy led string, such that the LED's Vf is only a few voltages lesser than the LDDs output


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## fietsenrex (Oct 8, 2014)

no can do 
each vero has it's own LDD since they require 30~36V (don't know exact) so adding a vero en series would exceed the limit of the LDD.
I'll also dig in the datasheet of the vero to see what the output is at 350 and 700mA
I've got them running on 1A currently but they get dimmed to 15% ATM maybe they will go a bit higher but I'm currently afraid that the ferts and CO2 can't keep up...
if they go to lower mA the PWM gets higher (for the same amount of light) which should in turn lead to smoother ramping, but then again I first need to test how much power on the lights is allowed by the CO and the ferts.


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## fietsenrex (Oct 8, 2014)

jeffkrol said:


> Just an unhelpful FYI..but there is a sound recording..
> 
> Drivers meanwell LDD....hum
> More..
> Meanwell LDD driver: for those who want to dim to 0 using Arduino - Page 114 - Reef Central Online Community


it's not that hum, mine is much much higher. 
well maybe it's the same if the sound gets distorted by the recording and playback


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## Arun. (Apr 30, 2016)

fietsenrex said:


> it's not that hum, mine is much much higher.
> well maybe it's the same if the sound gets distorted by the recording and playback


What does it sound like? Like MOSFET switching noise?


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## fietsenrex (Oct 8, 2014)

don't know never heard a MOSFET switching.. 
It sounds like a phone charger in "idle"


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> don't know never heard a MOSFET switching..
> It sounds like a phone charger in "idle"


Never noticed any phone charger noise either..


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## fietsenrex (Oct 8, 2014)

Think your hearing is damaged


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> Think your hearing is damaged



Maybe a 230/50Hz vs 110/60Hz thing... 
This other person was not a native english speaker but no clue if he/she was US or not..
http://forum.arduino.cc/index.php?topic=195820.0
Seems like they are probably in Italy..
http://www.reefcentral.com/forums/showthread.php?t=819212


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## Arun. (Apr 30, 2016)

jeffkrol said:


> Maybe a 230/50Hz vs 110/60Hz thing...
> This other person was not a native english speaker but no clue if he/she was US or not..
> Drivers meanwell LDD....hum
> Seems like they are probably in Italy..
> strange worm - Reef Central Online Community


the second link is about worms


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## jeffkrol (Jun 5, 2013)

Arun. said:


> the second link is about worms


acron was the poster at Arduino and here.. and since they didn't list their country I found their worm post w/ this:
t


> his is my first post in this forum. excused the writing errors but are ItalianÃ¢â‚¬Â¦I would have need of your aid.


so I guessed they were in Italy.. 
Thus 2 hums and both in counties w/ not 110
220/50cps

Then again jedimasterben also had some buzzing.. and I'm pretty sure he is in florida..


> I didn't think about it much after that. I think Spencer might have changed the output frequency of the controllers through firmware updates, but I am not 100% on that.


so rally leaves us nowhere.. "sigh"..


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## fietsenrex (Oct 8, 2014)

haha worms xD
anyhow, shouldn't matter if the grid is 230V/50Hz or 110V/60Hz..
everything is powered by DC.
controller gets 12V DC and the LDD's get 48V DC
there are no 230V power cables running to the topside of the tank, the power cables in the cabinet are spaced at least 5cm from any signal carrying cable (PWM, sensors etc.)


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> haha worms xD
> anyhow, shouldn't matter if the grid is 230V/50Hz or 110V/60Hz..
> everything is powered by DC.
> controller gets 12V DC and the LDD's get 48V DC
> there are no 230V power cables running to the topside of the tank, the power cables in the cabinet are spaced at least 5cm from any signal carrying cable (PWM, sensors etc.)


Yea, probably right..There are hundreds of people running  LDD's but 2 out of 3 w/ "hums" are not on the us grid. 
Kept thinking about some weird harmonics/noise/emf getting to the inductors.. somehow.. Shot in the dark.. not really a good one now that I think about it.. 
http://www.iaeng.org/publication/IMECS2014/IMECS2014_pp683-686.pdf


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## fietsenrex (Oct 8, 2014)

well, that is odd that most of the "hums" are not on US grid.. 
so you suggest that the difference in frequency (50/60Hz) could be the cause of the "hum" ? 
this could leave a different ripple on the DC which causes the LDD to "hum".. 

Arun PMed me suggesting to place a 1uF or smaller capacitor in parallel between DIM and - 
with the new boards i can easily install a small capacitor between PWM and - which should do the same..

first I'm going to try to change the PWM frequency, if that fails I can install some capacitors..


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> well, that is odd that most of the "hums" are not on US grid..
> so you suggest that the difference in frequency (50/60Hz) could be the cause of the "hum" ?
> this could leave a different ripple on the DC which causes the LDD to "hum"..
> 
> ...


Or put them in tin cans... 


> The circuit should be in a metal screened enclosure, such as a tin can. If it is not the inductor coil will be susceptible to ambient radiation. Inspect the place where you are operating the circuit. Is it near an AC-DC power supply, a PC computer or screen, a mobile phone, a radio, an MP3 player, etc? The normal 40KHz frequency of a switching PSU (your circuit) is similar to digital audio stereo at 44KHz. It is also similar to other switching PSU’s.


if changing frequencies doesn't work..
https://www.eeweb.com/electronics-f...enerated-in-the-inductor-of-a-buck-regulator/


> Thank you all for taking the time to answer my question.I really appreciate your sense of understanding and Support. The problem was eventually solved by adjustment of PWM SIGNAL FREQUNCY as suggested above.I went through the datasheet of the chip again and i realised that the frequncy range of pwm-signal should be between 100Hz and 2Khz.My Initial frequency was more than 2Khz so adjusting it to 100Hz removed the noise. Once again thank you for the Support and guide. Best regards.


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## fietsenrex (Oct 8, 2014)

yeah tin cans... I strongly doubt its due to EMC issues though
I still need to build some enclosure for the boards so a Faraday cage would be an option 

adding a capacitor would act as a smoothing device for the ripple?
sorry for my crude word selection, I don't know all the English terms for all the circuitry and devices and applications


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## Arun. (Apr 30, 2016)

shunt capacitor


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## fietsenrex (Oct 8, 2014)

thanks, I'll look in to that 
but first I've got another problem...
the PWM signal seems to get lost sometimes, which causes the lights to flicker.. or at least that is my guess..
already swapped the AWG26 out for breadboard jumper wires, which frankly is an improvement..
AWG18 (used for the power cables) is simply to thick to fit in the holes, (well they fit but I cannot fit a second wire for the next LDD)
so.. guessing i should go with bigger wires? the humm has also decreased some..


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## fietsenrex (Oct 8, 2014)

well, I've set the frequency to 1/4th of the original frequency, it has shifted from a phone charger in idle to a CO2 leak...
which isn't bad cause I know my co2 is fine but will get me searching for imaginary leaks


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## fietsenrex (Oct 8, 2014)

might be a dump question, but would the power consumption get cut in half if I replace the LDD-1000H with LDD-500H and keep the light output the same.

they run now at 10% of their full power on the LDD-1000H, so swapping out the 1000h with something like 500H or 350H would result in something like 60-80% usage of the full power.
but would it also result in less power usage?


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## jeffkrol (Jun 5, 2013)

fietsenrex said:


> might be a dump question, but would the power consumption get cut in half if I replace the LDD-1000H with LDD-500H and keep the light output the same.
> 
> they run now at 10% of their full power on the LDD-1000H, so swapping out the 1000h with something like 500H or 350H would result in something like 60-80% usage of the full power.
> but would it also result in less power usage?


THIS is what the output of an LDD at 50% looks like (exact one doesn't matter per se)









Point is a 1000mA @ 10% would average current to 100mA over time.. doing 10% 1000mA.... 90% 0 mA
Running a 500mA at 20% equals 500mA 20%// 0 mA 80% another effective of 100mA over time.


Changing drivers but keeping output equal has little effect on consumption.. 
....


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## fietsenrex (Oct 8, 2014)

thought that was what was happening with the drivers pulsing but wasn't sure..

thanks for the clarification!


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## fietsenrex (Oct 8, 2014)

Well, the lights work like a charm now.
I thought lets get the fanspeed controlled with PWM.
Got a BC547B and fitted it, it worked but it blew up within a minute..

Wired it as follows:
-ps minus to C
-PWM to B 
-PWM ground to C
-fan minus to E

With PWM ground to E the speed control didn't work

Now the big question, Did I wire something wrong? Or is the transistor not powerfull enough?

I run 6 12v fans (2x3) on 24V.
Just the standard makersled fans that come with the heatsink


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## saiko (Mar 30, 2007)

I dont think that is entirely looking correct with the connections(unless you got a typo somewhere)
Because collectors shouldn't be connected to PS minus/ground for this run.

Try doing the below way, replace the diode and put your fan in there, and tie up all the grounds together.










BTW- how did you resolve the humming sound from your drivers?


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## fietsenrex (Oct 8, 2014)

so just an NPN transistor in the + wire of the fans?
I fitted it in the - wire since NPN indicate that the collector and base are negative.

in the atachment is a picture of how I wired it


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## Nordic (Nov 11, 2003)

BC 547 is very lightweight for anything larger than low current LED's. Rather use TIP31, with a TO-220 heat sink attached.
Collector and base pins (1 &2) are swapped on the TIP.


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## fietsenrex (Oct 8, 2014)

figured that the bc 547 was not sufficient for such currents..
I was thinking of using a TIP120 for running the fans, would that work with the schematic from my previous post?

looking at the datasheets the TIP120 can handle a bit more current on C-E but way less on B-C.
B-C shouldn't be an issue I guess since an arduino also only goes as high as 40mA, the TIP120 can take up to 120mA


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## MrMan (Dec 5, 2014)

You'll want a resistor between the Arduino and Base of the TIP120. The base-emitter is a diode so if you wire the arduino pin directly to the base you're basically applying a short on that pin. Adding a 1k resistor will limit the base current to ~5mA which will let the collector current go up to 5A since the transistor gain is 1000. FETs you don't need the resistor since they are based on a voltage potential input, but transistors you need to set the B-E current to a reasonable value.


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## Nordic (Nov 11, 2003)

I wouldn't use the darlington Tip120 in this example. The tip31 should be more than adequate and they basically have the same thermal limit due to similar TO-220 packaging. (about 25W at 25C if memory serves).


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## fietsenrex (Oct 8, 2014)

Allright, I'll add one

But just to be sure, NPN transistor in the + or in the - wire?


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## fietsenrex (Oct 8, 2014)

well, got everything fitted...
fan- on collector, PS- on emitter, PWM+ on base and PWM- on emiter

fans run and respond to changes in the PWM signal, so that is a succes.
but, it gives a terrible humm.. really loud..
the PWM frequency is set to 400Hz to keep my LDD humm free, but at the lower end of the PWM the switching of the transistor is almost notable.

on one channel I had a 4.7K resistor fitted, but nothing happens if I use it for this "project" all the other channels are fitted with 100R SMD restitors (if I recall correctly)
fitting a 1K or 2.2K resistor or a combination of the 2 didn't work, but the 4.7K channel had only a very small almost not noticable humm (although it wasn't able to run the fans)

I tried fitting a diode between the C and E like so:








but found out it was a 2A shottky diode... but it only made the humm pulse.. 

so I'm guessing now that I need to fit a normal diode which is rated at 5A?


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## Nordic (Nov 11, 2003)

You could parallel 3 of the 2A diodes for 6A rating.

Also make sure all your ground connections meet at one point (ground star).


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## fietsenrex (Oct 8, 2014)

That also works with shottky diodes?


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## Nordic (Nov 11, 2003)

Schottky diodes have a bit of an excessive Vf drop when you parallel them.

I always keep all old electronics to pirate parts from when I don't have them in the parts bins.


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## fietsenrex (Oct 8, 2014)

so it should be doable with 3 shottky diodes?


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## fietsenrex (Oct 8, 2014)

well, still got a terrible humming sound...
got up to 4 diodes fitted, but it doesn't help anything with the humming sound 

could a shunt capacitor a solution?


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## Nordic (Nov 11, 2003)

It might reduce the slew rate a bit.
Have a look at http://ww1.microchip.com/downloads/en/AppNotes/00771b.pdf

Just in terms of practical application, where is your diode mounted? I would slap it straight over the pins of the fan.
Driving fans quietly, even without PWM can be black magic. I've tried and given up a few times in using fans for audio projects.

Which pin are you using for PWM and which arduino are you using? Some have a set of faster PWM pins (5 and 6).

http://provideyourown.com/2011/analogwrite-convert-pwm-to-voltage/
Here you can look up making a low pass filter that is below your switching frequency.
I've only been following your thread with one eye... for higher current apps you will need an inductor based filter.


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## fietsenrex (Oct 8, 2014)

well, to be honest it is fitted in a breadboard so I can easily test out different circuits.. 
but, it uses the PWM of port 9 I think on the mega, but the humming sound comes from the TIP120 not from fans.


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## O2surplus (Jan 31, 2010)

20hz to 20Khz is the range for normal human hearing. Raising the PWM frequency of your fans to beyond 20Khz will solve your problem. I use an Arduino Nano programmed as a PWM signal level shifter to accomplish this. The Nano uses analog pin (A0) as an input and reads the duty cycle of any PWM present. It then outputs a 25Khz copy of the PWM signal on pin D10 using the same duty cycle. 
The software can detect - 0%PWM (LOW), 1 to 99% PWM, and 100%PWM(HIGH) and drive the fan accordingly. Here's the code-


```
// Reads the PWM signal duty cycle and frequency from Analog pin A0
// and outputs the same PWM duty cycle to pin D10 @ 25Khz for quiet cooling fan control.
// last updated 1/29/2016 by Aaron Kovacs

#include <TimerOne.h>

#define READ_PIN A0  // analog pin A0
#define PWM_OUTPUT 10 // digital pin D10 
int dutyValue = 0;
int inputState = 0;
static double duty;
static double freq;
static long highTime = 0;
static long lowTime = 0;
static long tempPulse;

void setup(){

pinMode(READ_PIN,INPUT);
Serial.begin(9600);
Timer1.initialize(40); // 25Khz PWM = (40). 
Timer1.pwm(PWM_OUTPUT, 0);
}

void loop(){
  // this section of the code determines the input's (A0) frequency/duty cycle(true 0 - 100%) 
  // A 25KHz copy of the original input signal is then sent to pin D10 as an output.
  // The serial monitor can be used to display the input duty cycle and the signal status of the output. 
  readPWM(READ_PIN);
  
  int dutyValue = (duty);
  dutyValue = map(dutyValue, 0, 100, 0, 255);
  int inputState = digitalRead(READ_PIN);
  
  if (tempPulse > 1){
    analogWrite(PWM_OUTPUT,dutyValue);
    Serial.print("Duty % = " );
    Serial.println(duty);
  }
  if (tempPulse < 1 && inputState == 0) {
    digitalWrite(PWM_OUTPUT,LOW);
    Serial.print("Input_State =  ");
    Serial.println(inputState);
    Serial.println ("Cooling Fan - OFF");
  }  
  if (tempPulse < 1 && inputState == 1) {
    digitalWrite(PWM_OUTPUT,HIGH);
    Serial.print("Input_State =  ");
    Serial.println(inputState);
    Serial.println ("Cooling Fan - ON");
  } 
}

//Takes in reading pins and outputs pwm frequency and duty cycle.
void readPWM(int readPin){
highTime = 0;
lowTime = 0;

tempPulse = pulseIn(readPin,HIGH);
if(tempPulse>highTime){
highTime = tempPulse;
}

  
tempPulse = pulseIn(readPin,LOW);
if(tempPulse>lowTime){
lowTime = tempPulse;
}

  
freq = ((double) 1000000)/(double (lowTime+highTime));
duty = (100*(highTime/(double (lowTime+highTime))));

}
```


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## ichy (Apr 6, 2015)

Wouldn't a simple H bridge solve your problems for hooking up your motors?


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## fietsenrex (Oct 8, 2014)

The arduino nano sounds like a plan if I cannot adjust the frequency on just 1 PWM pin.

An H-bridge seems like a circuit to use if I want to turn the fans in the opposite direction. 
I don't know how that could solve the humming produced by the transistor, but then again I'm quite the novice when it comes to electronics.

Would a lowpass filter work on a PWM signal used on a switching transistor? Since they only mention mosfets..


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## Nordic (Nov 11, 2003)

I think you should modify it to use pin 4 or 13 for PWM, as they run twice as fast as the other ports.
Also, the diode bothers me there, those transistors already have diodes internally. I would rather use a diode over the poles of the motor to fight inductive kickback.


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## fietsenrex (Oct 8, 2014)

I've tried the diodes over de + and - of the fans, makes no difference 
Fitted them between C and the + from the PS

I asked rob already (since I use the robo-tank) but the lights don't use the PWM of the arduino. 
The PWM used by the lights is generated by a chip..


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## Nordic (Nov 11, 2003)

The diode over the fan or any coil for that matter is just good practice. I still don't like that tip120 for switching duty. 

You may want to try and run the earth connection on the fan directly to the negative pole of the power supply, i.e. not shared with the digital grounds.

Have you looked in your parts bin if you have something to make a low pass?


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## Nordic (Nov 11, 2003)

Sorry for second post, I had to go look for an example image first.










Here is a way to isolate the fan using an optocoupler, so you can drive one part of a circuit from another without them being electrically connected. (once again notice the correct application of the diode...not important for noise but for protection of the circuit)

http://www.bucek.name/pdf/cny75.pdf

Back to your drawing of the circuit...
The black wire from the arduino (I assume earth), could you disconnect it from that spot on the breadboard and reconnect it as close as possible to where you plug 0V line in from power supply. I suspect we might just have a ground loop hum. Otherwise, it is probably the Darlington that is screwing you over.

What voltage is the PWM signal coming from the controller?if you have 2 1K and one 330R (or five 1K) resistors we can try and bias the transistor more optimally at 1.5mA @3V Base voltage, current gain is about 1000 at 3V, so it should drive 1.5A through the transistor.


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## Nordic (Nov 11, 2003)

OK trying to look at this again.. it keeps bothering me.
So you are driving 6 fans (assuming PC fans), that is 6 x 250mA =1.5A So you are driving 18W with that transistor... not going to happen without serious cooling...
With larger fans say about 440mA, you are looking at driving 30 odd Watt.... Again not going to happen with one TO-220 transistor.


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## fietsenrex (Oct 8, 2014)

A tip120 should be able to run 5A, so amps shouldn't be an issue
And should be able to run up to 60V.
As for the 18W.
The system is running on 24V, so there "only" runs 0.75A through the transistor 

But there is a heatsink fitted on the transistor


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## Nordic (Nov 11, 2003)

fietsenrex said:


> A tip120 should be able to run 5A, so amps shouldn't be an issue
> And should be able to run up to 60V.
> As for the 18W.
> The system is running on 24V, so there "only" runs 0.75A through the transistor
> ...


Cool I'll look at it soon.
Busy moving fish to put my new batch of bushy nose Ancistrus in.

Have you tested the ground loop yet?


There was also a nice suggestion on using a higher frequency, these transistors are pretty noisy at low frequencies. The driver I designed for my LEDs runs at 40K for that reason (as well as preventing ghosting with digital cameras).


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## fietsenrex (Oct 8, 2014)

Nope, got some left-over month at the end of my salary.. in other words I've depleted my hobby budget.

So new parts are on hold till the end of the month when I get my next paycheck

But ghosting on camera's?


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## fietsenrex (Oct 8, 2014)

O2surplus said:


> 20hz to 20Khz is the range for normal human hearing. Raising the PWM frequency of your fans to beyond 20Khz will solve your problem. I use an Arduino Nano programmed as a PWM signal level shifter to accomplish this. The Nano uses analog pin (A0) as an input and reads the duty cycle of any PWM present. It then outputs a 25Khz copy of the PWM signal on pin D10 using the same duty cycle.
> The software can detect - 0%PWM (LOW), 1 to 99% PWM, and 100%PWM(HIGH) and drive the fan accordingly. Here's the code-
> 
> 
> ...


thanks, the nano did the trick 
no more humming and it responds to the PWM as intended.


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