Meanwell LDD driver: for those who want to dim to 0 using Arduino
- Thread starter pwreef
- Start date
Chock up one more advantage for the LDD drivers. For the cost of $12 or less you can get a separate string of lights as opposed to another meanwell driver for $30 or more. Also more flexibility being able to run one LED or 12 on a string, as opposed to an ELN driver which has a maximum and minimum LEDs per power supply.
Dave Thebrewguy
New member
LOL, it's even better than that. On a 56 volt power supply the LDD-H can put out up to 52 volts. My Luxeons all seem to have a Vf of 3 to 3.06, you could put 16 of them on a string.
If do not know if I will ever have a string that long because I want control of each individual colors, but if it is possible to put on or two LEDs on a string for the cost of a LDD controller and you are limited only by the Voltage of the power supply, is there a reason not to buy a 56 volt power supply?
I am thinking of overbuilding for future proofing things. I am thinking of my next tank. I am working on my next tank, I mean my next next tank.:rollface:
bhazard451
New member
You would be better off with a 12v or 24v power supply. They are constant voltage, so they will always be sending the voltage despite the number of leds.
If you bought a 48v power supply and only hooked up two leds, they would explode in seconds. You have to divide ps voltage by the fv of the leds you use to see how many you should run on a string. 48v/3.0fv = ~16 leds max. 12v/3.0fv= ~4 leds. Its a waste of an LDD-H though, as they can handle 48v.
+1 The LDD doesn't provide a "free lunch" electronically speaking. Forcing the LDD to drop too much voltage will cause it to get hot, as the "left over" electricity has to go some where, and that "somewhere" is heat. It's best practice to try to closely match the supply voltage to your led's strings required voltage for optimum efficiency.
megadeth72
New member
uhh it's not using a resistor to drop voltage
Well, if you want to get REALLY technical - no.
It is using resistance though, but as a side effect.
It's probably not a linear regulator. It is almost certainly using a switching mode voltage regulator. Although the switching is fast, there are some losses - and the more often it has to switch to reduce the voltage to keep the current steady, the more the loss builds up. There's always a little hysteresis with any semi-conductor switch.
Basically, the thing will turn on or off a transistor (of some sort or another) to switch voltage into a capacitor. As the transistor is either off or on, there's very little loss (resistance), but the switch time has a 'ramp' which will have some loss.
Like with any regulator, the thing will get hot the more work it has to do. Depending on the technology, it may be LESS hot than a plain resistor or linear regulator - yes.
Anyway ... my dilemna is that I want to be able to 'sequence' the pods in my setup across the tank, so I need to run a 4/2/1/1/2 setup (4 RB, 2 NW(or CW), 1 T, 1 R, 2 V). I'm planning on 8 of these pods on my 120G, but for now, I'm just doing 4 (I still have a 250W MH on the tank).
So, here's the thing - if I dim each pod separatly, then I need to run 1 T, 1 R, and 2V each on their own separate 600mw LDD.
I'm using 19.5V old Dell laptop power supplies for this (it's amazing how consultants beat up the wires).
The other options was maybe running the RB and NW's on their own separate controllers, and lump all the exotic LED's under just one controller for each bank. In other words, all the T, R, and Violet LED's on their own controller, across the 2' width of the tank, then just sequence the 'white' lights (the RB's and NW's).
Hmm ... not sure if that was clear.
== John ==
It is using resistance though, but as a side effect.
It's probably not a linear regulator. It is almost certainly using a switching mode voltage regulator. Although the switching is fast, there are some losses - and the more often it has to switch to reduce the voltage to keep the current steady, the more the loss builds up. There's always a little hysteresis with any semi-conductor switch.
Basically, the thing will turn on or off a transistor (of some sort or another) to switch voltage into a capacitor. As the transistor is either off or on, there's very little loss (resistance), but the switch time has a 'ramp' which will have some loss.
Like with any regulator, the thing will get hot the more work it has to do. Depending on the technology, it may be LESS hot than a plain resistor or linear regulator - yes.
Anyway ... my dilemna is that I want to be able to 'sequence' the pods in my setup across the tank, so I need to run a 4/2/1/1/2 setup (4 RB, 2 NW(or CW), 1 T, 1 R, 2 V). I'm planning on 8 of these pods on my 120G, but for now, I'm just doing 4 (I still have a 250W MH on the tank).
So, here's the thing - if I dim each pod separatly, then I need to run 1 T, 1 R, and 2V each on their own separate 600mw LDD.
I'm using 19.5V old Dell laptop power supplies for this (it's amazing how consultants beat up the wires).
The other options was maybe running the RB and NW's on their own separate controllers, and lump all the exotic LED's under just one controller for each bank. In other words, all the T, R, and Violet LED's on their own controller, across the 2' width of the tank, then just sequence the 'white' lights (the RB's and NW's).
Hmm ... not sure if that was clear.
== John ==
megadeth72
New member
the chip used to drop the voltage was posted a few pages back, it's probably not the exact chip, but similar
Ok- I reworked the connections to use 2 position screw terminals that can be purchased dirt cheap on FleaBay. You'll need 10 per board but they can be had for less than 25 cents each. Just look for 2 position screw terminals w/3.5mm spacing. Here' the PCB and the files needed for production at ITead are attached.
Well - ive just ordered 10 5up LDD boards and DIL sockets and 2 pole PCB screw terminals to suit! - will get pics up when they arrive and ive soldered them up
Thanks again! :dance:
Project Box?
Project Box?
I have...
LDD driver boards working. Check!
Power Supply hooked up. Check!
Reef Angle 5v PWM dimming working. Check! :beer:
and my inquisitive wife asks me... "What are you going to put that in?"
I was speechless. Any bright ideas out there on a professional looking project box with high WAF?
Project Box?
I have...
LDD driver boards working. Check!
Power Supply hooked up. Check!
Reef Angle 5v PWM dimming working. Check! :beer:
and my inquisitive wife asks me... "What are you going to put that in?"
I was speechless. Any bright ideas out there on a professional looking project box with high WAF?
Dave Thebrewguy
New member
My drivers are mounted above my heatsinks in a floating canopy. How are your heatsinks mounted? Can you put the drivers there? If so, all you need to do is run a data cable for PWM and a pair of conductors.from the power supply.
My power supply is behind the tank and my RA is in the stand. (Control head inside the door, the rest on the back wall.)
My power supply is behind the tank and my RA is in the stand. (Control head inside the door, the rest on the back wall.)
one clownfish
Member
Check out Craigslist. I found about a dozen computer towers for under $15 with the power supplies, PS wire, fans, and heat sinks still in them.
Dave,
I am using two MakersLED heatsinks that will be suspended
over the 75g in the living room. Am hoping to keep the hardware above the tank minimal and do away with the old oak canopy. One small project box, one cat5 cable and one 48v power cable sounds good.
One clownfish,
Duhh.. I have a old SCSI external drive case at work that might work nicely for the power supply.
Thanks guys!
I am using two MakersLED heatsinks that will be suspended
over the 75g in the living room. Am hoping to keep the hardware above the tank minimal and do away with the old oak canopy. One small project box, one cat5 cable and one 48v power cable sounds good.
One clownfish,
Duhh.. I have a old SCSI external drive case at work that might work nicely for the power supply.
Thanks guys!
What are the DIL sockets about? Are these mounted into the PCB so the LDD chips can be stuck in then to the PCB to be later replaced or changed out as needed?
Can someone give me parts numbers for the DIL chips and screw terminals from digi-key?
Can't give you part numbers, I got mine from fleabay.
Search 24pin dil socket.
Just make sure they are for machined/turned pins.
They do do exactly as you say though, means you can swap out the drivers as and when you like without having to bother with desoldering them from the pcb.
Is there a way to efficiently run a varied length string lights efficiently. For example, I am trying to run two sets of LED for two tanks, with one controller and one power supply. The main tank might have 12 royal blue 6 white and 4 blue 2 moonlight and a string of four with UV red and green. I would like to be able to control each of these colors or strings separately but do not want to put a burden on the LDDs leading to potential meltdown.
Is there a way to put resistors in place to help ease the burden on the LDDs so they don't have to do all the work? Otherwise it seams to diminish the perceived advantages of this control method.
