New 12 channel, dawn/dusk LED control board

[MicroMan]

I am an engineer by day and a fellow aquarist and herp enthusiast at night. I am always looking for new ways to create natural biomes for my home and designing innovative electronics to support this hobby is my passion. My twenty years of digital engineering design experience as well as my connection with fish, herps and botany since childhood and during my college years fuels this passion.

 

Soon after deciding to build a planted tank, a reef tank and a poison arrow frog biome, my latest electronic project started when I became unsatisfied with currently available LED control options. I quickly realized that this controller may be something that other enthusiasts would also be interested in and at an affordable price (hundreds rather than thousand of dollars) so I decided to post to this forum to let DIY folks know about it.

 

I am new to this forum, so please allow me to briefly tell you about what it is and how it works.

 

My design is a fully programmable, 4” x 6”, 12 channel, micro-controlled LED control board with a USB connection. Each of the twelve channels can support up to 6 high –power (3W) LEDs for a possible total of 72 LEDs and can be hardware programmed to support a constant current from 100mA to 1A. Each channel can be manually set for an intensity value from 0% to 100% of full intensity in 1/10 percent increments (0 to 1000). Up to 4 photo periods in a 24 hour day can also be assigned to each channel. Put simply, in automatic mode, these 4 photo periods replicate morning, mid-day, evening and night. For each period, the micro-controller firmware automatically controls the increase/decrease transitions for each LED channel creating a very smooth dawn to dusk effect. This can also be used to control a designated moonlight channel. For larger installations, several controllers can be used to cover full lighting requirements.

 

At present time, the aforementioned capability has been tested and is completed. I believe that this design is very versatile and can be adapted to nearly any lighting project. The design also supports future firmware upgrades via PC as they become available. In the works is automatic lunar phase control, cloud cover and lightning simulation and a Windows XP/7 based graphic user interface. I am also considering the development of a WIFI based hardware adapter to allow remote control from a PC to further the controller capabilities in a large multi-controller installation.

 

In closing, my desire is to work closely with other DIY people in fulfilling their particular lighting needs, learning from their personal experiences and subsequently enhancing my own knowledge, experience and energy in a hobby that I love. I would be happy to answer any questions or provide more information to anyone interested in learning more about this control board via this forum. Thank you.

[1.0reef]

That ... sounds ... awesome!

Pics

[MicroMan]

My apologies for not including a photograph! Here is an image of the board that currently has only 3 channels populated with drivers. I have also attached an image of the board connected to a simple planted tank light board that uses CREE CW/WW and cool blue moon LEDs.

 

Ironically, the only design problem I have had so far is that I have selected an LED driver that seems to be in high demand and currently difficult to get a hold of in quantity. I suspect that it is due to heavy use in the auto industry. In any event, I am hoping that quantity will be available soon as I am eager to get to my next reef project which uses 6 channels of CW/RB and 5 channels of exotics.

 

Thanks for your interest.

[MicroMan]

When time allows, I will also post a video online that shows the controller in action.

[1.0reef]

Very nice, I like the avatar, IMO it fits your personality.

[MiReef]

Hi,

Are you using CAT1401 chip. I think it is a linear driver. Do you think they will heat up if you mix different types of LEDs with different current requirements?

[MicroMan]

Excellent question! The short answer is yes. The longer answer is that it depends on the cumulative VForward of the LEDs on a channel vs. the system input voltage as well as channel current and duty cycle. I feel that I adequately followed the manufacturer's thermal guidelines, but since this is geared towards DIY LED lighting, there is a LED layout recommendation that I would make to anyone interested in using this design.

 

Since heat is a product of current, excess "undropped" voltage and duty cycle in this case, I would not be too worried about some of the lower current, lower duty cycle LED applications such as the exotics at LEDGroupBuy.com or LEDs intended for relatively low output moonlight applications. However, I would recommend that the main "work-horse" LED channels (CW/NW/RB), typically driven from 700mA to 1A current and usually at 100% duty cycle at mid-day, be setup so that total VForward is roughly the same for all of the "work-horse" channels. The system input voltage could then be tuned to be slightly more than the cumulative VForward of these channels.

 

I understand that every DIY lighting design is unique, but this simple guideline would dramatically cut down on heat.

[MiReef]

Thanks for the answer. I may have a idea to cut down heat for the mix of workhorse and aesthetic leds. Can you use a variable sense resister for each channel so that you can adjust the highest current per each channel so that total wattage to dump can be limited. I think CAT 1401 can handle 6W max and with a small heat sink on CAT chip we can run a combination of LEDs.

 

Actually I am planning a driver that has 8 CAT chips and these have a sense resister restricting current to ~900 mA and trim pot to adjust it further to suit different LED strands. There is a whole discussion in RC and I bought this driver from on of the members there. I might so a build thread in the future when I get all the parts.

[MicroMan]

You could certainly mix different LEDs on each channel. You would just need to be certain that each LED on a particular channel could handle the current set for that channel. My current designs do not mix different LEDs on any channels however. I personally think that it is safer to assign the same LEDs on every channel given the different current requirements of LEDs as well as the fact that each channel is intended to have individually controlled duty cycles (intensities) over the course of a 24 hour period.

 

For example, I have attached a photo of my current 15" x 15" reef light design. You will notice that I get a very good blend of LED colors all with individual channel control. In this way, I can easily "tune" the colors that I want at any time with custom intensities. This was the main reason that I went with 12 channels.

 

Having said that...I really have no clue how it going to look until I put it all together and start tweaking colors! But that is the fun of DIY isn't it!

[MicroMan]

Here is a smaller design that I am doing over a 10 gallon rimless planted shrimp tank. This one uses only 5 channels in this case. The blue LEDs will be assigned to a moon channel and will be lunar phase controlled.

[pwreef]

Excellent work! Are you planning on selling these? Did someone manufacture these boards for you, or did you do it at your place of employment? I see that CAT 4101 is in short supply, have you considered using a driver like PT 4115? http://www.micro-bridge.com/data/CRpowtech/PT4115E.pdf

[bhazard]

If you ever plan on selling these, let us know because I'd be very interested.

[MicroMan]

I had the boards fabricated by an outside vendor at my own expense. While the upfront fabrication cost was high, the distributed cost per board is actually fairly low and this is what makes it possible to share this design with other enthusiasts at a reasonable price. I would like a little more time to really wring out the design with more energetic layouts, but the plan is to make the board available to anyone interested in purchasing it for their own DIY applications as soon as I am comfortable with design performance. I have not yet done a complete cost analysis, but I would think that the current board design would be less than $300....but that is just a ballpark guess at this point. Thanks for your interest!

[MicroMan]

The PT4115 is an interesting part indeed! I see that it is a switching regulator and would definitely run more efficiently than the linear CAT 4101. Like any switching regulator though, there is always more design tweaking to get it running in it's sweet spot over different temperatures and loads. I am fairly confident that the linear CAT4101 will perform nicely however. It would not be until I ran into thermal problems with the CAT4101 that I would seriously consider switching to a new part at this point though. If interest in this design begins to grow, I believe that I can secure larger quantities of CAT4101 to complete boards as necessary. Thanks for the PT4115 information.

[bhazard]

$300 isn't bad at all for a controller and 12 drivers/channels. I would love to create a build to simulate a nicely blended left to right cloud movement and more with that many channels. If it dims all the way down to 0% smoothly, it would be great over meanwells for me as well.

 

I could create a light equal to or better than a 5ft Vertex for my 120 gallon, for less than a grand.

[MicroMan]

$300 isn't bad at all for a controller and 12 drivers/channels. I would love to create a build to simulate a nicely blended left to right cloud movement and more with that many channels. If it dims all the way down to 0% smoothly, it would be great over meanwells for me as well.

 

I could create a light equal to or better than a 5ft Vertex for my 120 gallon, for less than a grand.

Just wanted to drop everyone a note that I am currently running a 5 channel setup ( 12 CREE XT-E Cool White @ 700mA, 12 CREE XT-E Warm White @ 700mA and 6 CREE 670nm Cool Blue @ 50mA) over a planted shrimp tank and the design works exactly as planned. I am running the board at +20VDC and there is very little heat loss on the drivers. I am confident that the board will work just as well for larger designs and I would like to make the board and firmware version V1.1 available to other DIY folks for their own use. Please contact me if you are interested. Thank you.

[Iyamu]

MicroMan - what happened to your blog on the pther group - I came back to link up and suare up and the entire thread was gone - poof!

I need to link up 1-1 to get going I'm now very late in the build.how can we link up?