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Discussion Starter · #1 ·
http://www.plantedtank.net/forums/20-diy/980633-how-use-tc-420-control-ldd-drivers.html

As a followup to the above thread and the success of using a TC-420 as a cheaper 5 channel programmer/timer (still chugging along btw) I thought it would work the same way w/ those manual dimmers. Like these:


Well I bought one for like $3 from China and "finally" got it (about a month).
Opened it up, found the "gate" leg. Soldered a wire to it and that wire now goes to the LDD PWM wire.

Works like a charm. Actually I attached a 12V ps to the input and also the LDD "in" to the same port.

I also wired in a 12v strip light to the "out" and a 3W test LED to the Meanwell ldd..

Both are now dim-able by the controller..
some things that could have caused problems were 1)voltage at the "gate" (had to be in the Meanwell acceptance range. 2.5-6v)
2) in the frequency range at the gate (100-1000Hz)
Couldn't measure it very accurately but it seemed to be around 4v at 500Hz (maybe it is twice that due to trying to measure a dc "wave"..
Anyways seems to be "standard" Aduino type numbers..
Yea
 

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i have tried it, it worked just fine i always wanted a manual dimmers for the LDDs, really thank you for the idea

but it won't work until you attach the same power in for this dimmers with the same power in for the ldds, so this means the maximum in voltage you can use with your LDDs will be only 24 as this is the maximum in for those dimmers this means the maximum voltage you can get from your LDDs will be only 20V this means you can drive only 6 leds

I hope we can find a way to separate the in power for both dimmer and LDD driver or some how we can manage to make those dimmer accept more than 24 volt

Thanks again it is a great idea
 

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Discussion Starter · #4 · (Edited)
i have tried it, it worked just fine i always wanted a manual dimmers for the LDDs, really thank you for the idea

but it won't work until you attach the same power in for this dimmers with the same power in for the ldds, so this means the maximum in voltage you can use with your LDDs will be only 24 as this
you can separate the power..
Use a 12V wall wart to run the dimmer..
Use any PS you want to run the lights..
I think I got a sketch somewhere.
Just don't hook the positive of the "big" ps to the dimmer.. But you do have to share grounds..but will check
Will get back to this..
Oh and by using the tap off the internal "gate" you don't need to power the dimmer w/ 12V either..
Internally there is a voltage regulator that feeds the op amp timer circuit that pulses the MOSFET base..The 12-24V is for the output of the mosfets, which you won't be using if just running ldd's

fixed..
 

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Discussion Starter · #5 ·
Got it working.. not sure why the first attempt failed .. but here try this..
9v DC ps to plus minus in
Larger power supply to minus in
LDD "input" negative to minus in (so you have 3 wires ganged into the mius in on the dimmer..
LDD "input" pos to large power supply positive..

Jumper wire from base of internal mosfet to dim on LDD..

Easy peasy..
IF you use a 12V in power supply you can still use the mosfet "outs" on the dimmer..

crude but you get the picture:




BTW best guess on pwm voltage and frequency..
>3V, 780-ish Hz..
 

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I tried it i powered the dimmer with 12v and powered the LDD with a laptop charger that gives 19v and i shared the ground as you told me it worked like a charm, thank you :D

but tell me how i can use this dimmer without powering it as you said ( you don't need to power the dimmer w/ 12V either.. ) sorry i didn't understand this part

And thank you for taking this time to draw this pic
 

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Will this work with a Finnex Planted Plus? I haven't checked what voltage it runs at.

Oops! I see it only works with the LDD drivers, not a commercial LED light. Right?
Out of the box it will work w/ the planted plus if you put it between the power supply and the light..
As long as you don't exceed the 6A rating.
90W at 15V..

It will work w/ any constant voltage array running 12-24V 6A.
Won't work w/ some of the larger Beamsworks.. ect..

The LDD is another "hack" to the controller..
I really should take a picture of it..

THIS is what you need to do for the LDD thing..


Hoppy you may be interested in the guy who split the 3 channels (W,R,B) and put a tc-420 and a couple of MOSFETS and now has a 3 channel progammable planted plus.. ;)

Here:
https://youtu.be/V3EdwQmYyk0

http://www.plantedtank.net/forums/20-diy/647434-diy-timer-dimmer-kind-4.html
 

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Discussion Starter · #10 ·
but tell me how i can use this dimmer without powering it as you said ( you don't need to power the dimmer w/ 12V either.. ) sorry i didn't understand this part

And thank you for taking this time to draw this pic
I meant if you are not adding strips you can power the circuit w/ other than 12V... Sorry for the confusion..
You have to power the dimmer w/ something..
Haven't checked on the real specs of the gate circuitry (probably won't either. ;)) but more than likely any ps 5v or above should work and only really a few mA,
Technically a 1 power supply system could be built using a voltage regulator..
Say 36V for the LED's and add a 12v voltage regulator to feed the dimmer..
Not exactly sure how you do the grounding for that one though..
 

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Old thread but I have to ask the question - why isn't this solution more common? I just put it together this evening and it's working fantastically! Easy too.

I have a Fluval Spec III that I've been delaying the lighting on. I have a nice 3-up LED but no real good solution for operating it. I'm not looking for multi-channel control but only simple dimming. I have some extra LDD drivers from another project but I wasn't about to buy a full PWM controller for this small light. The objective here is a cheap light that works well.

I found this based on some research I was doing on using a 555 circuit as a PWM source but this looked easier and it came with a housing too. Also the housing was big enough that I ended up just mounting the LDD driver inside it and then adding a plug that would go directly to the LED.

Total cost for a nice powerful light for my 3g Spec? Conservatively $25. That's $5 for a 12v power supply, $5 for a Meanwell LDD, $5 for this PWM dimmer, and $10 for 3-4 LEDs. I suppose the only additional piece of hardware I might want is a wall timer which is another few $. Could likely get everything cheaper as well if you're willing to wait for shipping from China.

Thanks a ton Jeffkrol for the information and the pictures it really made the project simple.
 

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I would wager it's not more popular because it just simply isn't as well known, and lots of people want an off-the-shelf plug-in solution. A bunch of people don't really care for having to modify products, or want a super-whiz-bang feature rich solution like an arduino type of controller.


You can also do a similar setup with a simple potentiometer, a MeanWell LDD1000-L, and a few diodes with a series resistor as a simple shunt regulator (or for this particular application, a TL431 shunt reference) to supply ~2.5v for the pot. Same setup would also work with the LDB-L series drivers, just with a 10v supply for the pot, such as the LM7810 which can also provide DC for your fan supply if needed, and the LDB driver has the added benefit of being able to supply higher voltage than your input voltage, which is handy for running smaller CoB type arrays (such as the Bridgelux Vero) on smaller tanks and setups. You could easily run everything off of a 12v supply this way.
 

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I would wager it's not more popular because it just simply isn't as well known, and lots of people want an off-the-shelf plug-in solution. A bunch of people don't really care for having to modify products, or want a super-whiz-bang feature rich solution like an arduino type of controller.


You can also do a similar setup with a simple potentiometer, a MeanWell LDD1000-L, and a few diodes with a series resistor as a simple shunt regulator (or for this particular application, a TL431 shunt reference) to supply ~2.5v for the pot. Same setup would also work with the LDB-L series drivers, just with a 10v supply for the pot, such as the LM7810 which can also provide DC for your fan supply if needed, and the LDB driver has the added benefit of being able to supply higher voltage than your input voltage, which is handy for running smaller CoB type arrays (such as the Bridgelux Vero) on smaller tanks and setups. You could easily run everything off of a 12v supply this way.
Can you expand upon the LDD-1000L and a potentiometer? I've tried a simple 1Mg pot on the LDD-1500L as per Meanwell's diagram in the spec sheet but all of the dimming occurs in the 0-10% range and the rest of the range is just full on. I've tried lower value pots but they have even less effect.
 

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Discussion Starter · #17 ·

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Old thread but I have to ask the question - why isn't this solution more common? I just put it together this evening and it's working fantastically! Easy too.

I have a Fluval Spec III that I've been delaying the lighting on. I have a nice 3-up LED but no real good solution for operating it. I'm not looking for multi-channel control but only simple dimming. I have some extra LDD drivers from another project but I wasn't about to buy a full PWM controller for this small light. The objective here is a cheap light that works well.

I found this based on some research I was doing on using a 555 circuit as a PWM source but this looked easier and it came with a housing too. Also the housing was big enough that I ended up just mounting the LDD driver inside it and then adding a plug that would go directly to the LED.

Total cost for a nice powerful light for my 3g Spec? Conservatively $25. That's $5 for a 12v power supply, $5 for a Meanwell LDD, $5 for this PWM dimmer, and $10 for 3-4 LEDs. I suppose the only additional piece of hardware I might want is a wall timer which is another few $. Could likely get everything cheaper as well if you're willing to wait for shipping from China.

Thanks a ton Jeffkrol for the information and the pictures it really made the project simple.
Well I tried the hack with an LDD-L1500 but it doesn't dim all the way down to 0. It stays at about 10% on and goes up from there. Does that only work (0-100%) with the LDD-H series drivers? What's the difference between the LDD-H & LDD-L drivers?
 

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Discussion Starter · #19 ·
The Ldd-H's and high current LDD-l's are more similar than the low current Ldd-l's and h's

As to PWM differences in frequency Ldd-l's >900mA only go to 500Hz not 1KHz..
Low current Ldd-ls PWM voltage doesn't go below 5..

Only low current Ldd-L's do analog voltage dimming..

ALL will smoothly dim to zero w/ 0-100% PWM duty cycles per spec sheets..
https://www.mouser.com/ds/2/260/LDD-H-spec-766227.pdf
http://www.mouser.com/ds/2/260/LDD-L-spec-47593.pdf

There is nothing obvious that would cause a difference.
Only "suspects" would be a faulty dimmer or possibly effects of too high of frequency (>500Hz) but that is unlikely..but not impossible.
I've personally never used LDD-L's
 
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