Arduino for LED control on Aquarium

Hello everyone, I've been lurking for a while and I believe that the arduino is something that can help me finish my DIY LED light for my reef aquarium. I currently have a 3 channel light that I built that utilizes Meanwell drivers that adjust current based upon a 0-10 volt reference signal that I currently attune via a 10k pot and a regulated wall wart from sparkfun. While this method works just fine for single level manual control, I would like to enhance the ability of the light. Specifically I would like to implement schedules where light is ramped up in the morning and peaks / sets much like the light on the reef itself. In addition to a standard schedule, I would like to include other schedules that would allow me for reduced acclimation periods for new corals, as well as simulate cloud cover etc.

The unknown for me at the moment is my shopping list, and validation that the arduino can do what I think it can do. I know PWM is possible; however, I'm currently tied to the 0-10v signal for dimming.

Thanks in advance for any help with my project!

Use the PWM to control a transistor to control the 10V.
How much current is the 10V putting out?

I am envisioning something like this.
PWM switches NPN transistor, which lets PNP transistor 10V being turned on/off, filter that to make smoother DC voltage.


I'll have to measure it, but I would imagine it's very small. The meanwell driver uses the reference voltage only to attune the maximum current that the LEDs can draw.

I know this sounded awfully familiar:

We also have a suggested circuit for generating 0V-10V using PWM:

-- The Arduino Drum Machine: 14-track MIDI drum machine sequencer / groove-box

Thanks for those links.

The dimmers that I have currently don't take a direct PWM signal. I apologize for my ignorance, I don't quite understand PWM and analog voltage. Meanwell has drivers that take PWM or what I currently have which is:

Looking at the schematic you posted, I realize that I'm a long way away from remembering anything from my high school EE class. I went the business path, and realized late that I'm a gadget guy at heart.

The circuit I posted does indeed put out an analog voltage (not PWM) which could replace a pot. Now to get that analog voltage, PWM is used (i.e., the analogWrite function from the Arduino), but the actual output to the Meanwell driver is a steady voltage.

Is that what you are looking for?

-- The Aussie Shield: breakout all 28 pins to quick-connect terminals

Yes, exactly what I'm looking for. Of note, the schem has pin 7 of the 2371 hooked up to a 12v source, could this also be replaced with my 9v regulated that I have now?

I assume that everything else I mentioned can be achieved as well? I envision an interface that is pretty basic. Up, down, confirm, back. Running one set lighting schedule at a time, and having all the lighting schedules loaded into memory. I actually like to have the schedule not on a 24 hour cycle, but a 7 day schedule where I can have a few days of intense sunlight, and then a day or two during the 7 day period of cloudy days.

This 7 day period would also enable an easy method of performing light acclimation for new livestock.

How about some part #s or links to the parts you have now installed now?

Of note, the schem has pin 7 of the 2371 hooked up to a 12v source, could this also be replaced with my 9v regulated that I have now?

Yes, but then the output will only go up to 9V and not 10V.

Everything else you mention is just a matter of programming logic and should be achievable. You are limited in memory to 2K of RAM but I doubt that will be insufficient to store a lighting schedule.

-- The Rugged Motor Driver: two H-bridges, more power than an L298, fully protected

I have:

Meanwell ELN-60-48D driver pushing 12 CREE XPG Royal Blue LEDs Meanwell ELN-60-48D driver pushing 12 CREE XPG Neutral/Cool White LEDs Meanwell ELN-40-48D driver pushing 4 CREE 420 nm LEDs and 2 505nm Cyan Luxeon LEDs

From Sparkfun: Reference voltage: Wall Adapter Power Supply - 9VDC 650mA sku: TOL-00298 10k pots are: Rotary Potentiometer - Linear sku: COM-09288

That's it, minus the wiring and on/off switches.

Of note 9v is fine, all it really needs is a range, as the Meanwell drivers have an internal adjustment screw that allows you to modify the current range manually.

Any suggestions or links to quality lit display screens that can show a nice amount of text for easy reading, and or User Interface buttons?

Thanks again to you both, I'm getting excited about this! I was starting to get bored without a project to tinker with!

I'm on right now, and I see a few different models of the TLV2371, any of them fine?

Also, CR I see your schematic, but I'm still trying to figure it out. Once I do, I'll post some questions back. grin