Powering the Rainbow flood

[gizmomkr]

I just put my first one together, and was testing with some 12v plug-in type transformers. That worked great, but when I tried to dim them, I realized ALL the 12v plugs I have have a regulator.

Im thinking I can just pick up some 12v transformers without rectifier's - I didnt see any reson the board wouldnt run off AC v.s. DC. Anyone else tried that ?

[Dan Ancona]

My plans are to use an old computer power supply (since I have several).

[Ponddude]

DO NOT RUN ON LIGHTS ON AC CURRENT!! They were not designed for that at all!!

However, if you are using a rectifier, in theory that should be fine, but be very careful. I had someone (can't remember who it was now) that used a full bridge rectifier that was putting out WAY to much power even though it was rated at 12VDC. He ended up blowing all the LEDs on his lights. Make sure that the rectifier is putting out 12 VDC exactly.

Also, I have said this time and time again...you should not be using wall warts that you plan on dimming!! Yes, some people have done it and have been successful at it, but the wall warts are ment for constant power all the time. By varying the intensities and fading and shimmering and twinkling, chances are very good they will stop working fairly quickly.

[Steven]

I have pre-built LED 4' tree that came with a 24-volt transformer. One time I accidentally put it on a channel that faded down. It worked for a while, but the next day it wasn't working.

I cut open the transformer to see why it failed and found evidence of damage due to extreme overheating (things were melted inside the case). This wont happen to most transformers because they will fail before getting that hot.

The point is, it won't work. Get a CMB-16D DC controller.

[gizmomkr]

I understand having a verry hard set limit on the input being no higher than 12v. Im sure the resistor values were picked to give the max allowed voltage to the LED's (maybe even slightly over MAX)

What is the technical reason NOT to allow / support propperly rated wal wart or raw transformer with half or full bridge rectifier.

Im not familiar with a straight Rectifier with a voltage rating that is not a regulator. If the component is acting as a regulator, it does me no good for dimming.

Are you simply afraid of inconsistencies in the transformer or AC Power causing a spike above 12v on the output side?

I just dont want to end up having to buy a LOR DC board just to drive the rainbow flood.

I dont want to turn this into another LOR protocol license war - But sure would be nice if the Rainbow controller could SPEAK LOR, instead of DMX.

i love LOR and love the rainbow line - I know this would drive the price up - but I think thats fine. Everyone deserves to get paid and make a profit - thats how the product evolves and how the employees of LOR feed there families.

I just dont want to end up with a LOR CMB-16D at 99.00 - to only use 6 chanels. If LOR made a CMB-3 or a CMB-6 for 45 - 65 bucks - Id buy it. If LOR doesnt want to make it (because not too many folks would want a 3ch controler) they should license it over so someone else can make it- because it would go great into that rainbow brain. Just my .02.

[Ponddude]

Trust me, if Dan is offering up the LOR protocol, I have pen and paper in hand!! However, I certainly understand why he doesn't release it....it is his business after all.

Anyway, can you send me an email with all the components or even a schematic of what you are planning. I would like to see what you are planning and will have a better idea of what you want to do. greg@christmasonmanor.com

[Max-Paul]

Good grief! Who ordered this?

I just got done readings so much gobely gook that my head started to hurt.

First Rectifiers are not regulators, these two items are two different things that do different jobs. They are not ONE and the SAME. Rectifiers change alternating current (AC) into direct current (DC). And a regulator takes any value higher than the rating of the regulator and pulls it down to not exceed the regulators value. But it will not raise up a lower value to the regulators value.

When you rectify an AC voltage to a DC voltage, the DC voltage will rise to 1.414 above the original AC voltage. Thus a 12VAC output of a transformer will become about 17 VDC unregulated and with ripple or dirty as some of us will call it. But you will not see this with a standard volt meter. Thats because a volt meter is rated to reads RMS. But if you put a cap. on it to remove the ripple then you will see this higher voltage. But even without the cap. your LEDs will see this higher voltage and if you do not take this into account, you will burn up your LEDs.

gizmomkr, electricity is a science and there are laws governing its action and reactions. I highly suggest you start learning Ohm's law, Watt's law and Kerkoff's (SP) Law. There are others but these are the foundations of electricity, and without them you are just bouncing off of the wall.

[gizmomkr]

Max,

I'm NOT an EE, but I have been tinkering since I was about 5. So, I thank you for your detailed breakdown. I do have a solid grasp of Ohms law, and I promise I am not going to run 20 amp loads on a piece of cat-5. (well not for long)

I fully understand a rectifier V.S. a Regulator - and while I agree they are two completely different electrical operations, I dont think its fair to say so quickly they are "NOT one in the same" when they are literally available in one packaged component. http://www.parkeryamaha.com/universal12vrectifierregulatorsnowmobile.aspx

Some folks may need a rectifier with a 12v regulator - I dont.

A Science with laws - That should be fun to learn (Like Mr. Wizzard) And sometimes the best way to learn is to burn up some board that took many hours to build. Or stick your finger to the back of a heatsink.

I couldnt tell you what pin of the first transistor circuit I incorrectly grounded, but you can bet your ass I wont touch another flyback transformer. Its the painfull lessons that sometimes make the best lasting impression.

[rstately]

gizmomkr wrote:

I couldnt tell you what pin of the first transistor circuit I incorrectly grounded, but you can bet your ass I wont touch another flyback transformer. Its the painfull lessons that sometimes make the best lasting impression.

I Agree, just like all this baby proofing everyone is doing. What ever happened to "natural selection"?

[Max-Paul]

rstately wrote:

gizmomkr wrote:

I couldnt tell you what pin of the first transistor circuit I incorrectly grounded, but you can bet your ass I wont touch another flyback transformer. Its the painfull lessons that sometimes make the best lasting impression.

I Agree, just like all this baby proofing everyone is doing. What ever happened to "natural selection"?

No fair rstately! you beat me to it. I suspect that gizmomkr is doomed to be next in line for the Darwin award.

BTW gizmomkr your rectifier / regulator is for a snowmobile is not the same as one that would be used in a house current / voltage situation. Two different beast. You best get some book learning before you try anything else. At least a book is not known to kill you like a flyback transformer or a few thousand other things that are electrically related.

[gizmomkr]

The LAWs used to tell us the earrth was flat, and that spec of land you call home didnt exsist.

QUESTION - and LEARN is my point. Thats the point of my thread.

I dont believe the glob of silicone and other bits inside the Snow Mobile Regulator / Rectifier will care if I string it to an automitive alternator or a 12 - 14v ac transformer in my livving room. Its of little signifigance as I dont have any use for 12v regulated power. I'm sorry my life doesnt revolve around digikey part numbers.

The question at hand would be if I have CLEAN 120v ac power, and I hook a 12v transformer to it, and a rectifier - whats the harm in using that to power the rainbow flood - If I know it wont output more than 12v

Post-it-note glue was a mistake untill someone experimented enough to apply it to paper. Ask, challenge, learn.

[Randy]

My opinion is that you could probably rig up something that will work as far as powering the Rainbow Flood, but the question is whether it will work well (especially during dimming, etc.)

A single Rainbow Flood draws about a little over 1 amp when all LEDs are on. So you'd probably want to start with an AC adapter that will put out 8.0-8.5 volts AC and can deliver 1.25 amps or so. Then you can add on a full-wave rectifier to that output with no regulator or filter capacitors at the output (that would affect the performance of what you're trying to achieve).

As long as you don't go over about 8.5 VAC out of the AC adapter, your DC output shouldn't go over about 12 volts to the Rainbow Flood after you rectify it.

But the DC that you'll be feeding the RF board with that setup will not be smooth pure DC, and that is where you'll have to experiment to see how it looks. Will it fade correctly? Will the LEDs look right? Will there be flicker? All of those questions you'll have to answer by experimenting.

If you had to go buy such an AC adapter new and build the rectifer, you may have $15-25 into that setup just to power one Rainbow Flood board. It probably makes better sense if you have these specific parts laying around, but if you have to buy these parts, and especially if you're trying to power several RF boards, I would probably go in another direction. You can get a decent DC switching power supply for $25 shipped on eBay, and a DC controller was under $100 in the recent sale. That will power and control several Rainbow Flood boards...

If you decide to go down the AC adapter route and plug into your AC controllers, I'd be interested in hearing how it goes....

I have a little experience in this area, as I purchased some LED twig trees from Target that were powered by AC adapters (AC output) and they had a rectifer on one tree for a set of 3. I powered them with an AC LOR controller, and ultimately had to put a C7 bulb in parallel with the trees to get them to look somewhat decent during fading. An extra 5 watts per set of trees was discouraging since they were supposed to be saving me energy(!). Ultimately, I decided to cut off the AC adapters and power the trees from a DC LOR controller with a DC power supply. The performance was much better, so I'm glad I did it that way. Similiarly, I think the Rainbow Floods will probably look better with a traditional DC controller and power supply, but it will be a good experiment to see how they might look if powered the way you're thinking...

I hope that helps you...

Randy

[TJ Hvasta]

This will be my first foray into the DC World also, with 4 (for now) RF kits. I'm planning to run them from LORs 16QC dc board, powered from an Astron 30a supply I used for my ham radios. I got the QC board during the sale, so I was able to spend a lil less than Giz will have to pay now. With 16channels available , and only 4 boards on hand, I think for the $15 per RF board, I may just get 4-6 more to make the controller really feel needed

Don, did you say you're running yours from a bench supply or a radio supply? I figure that both the Astron and Midland supplys are well-enough regulated to provide a clean source of DC. How long is the line from your supply to the controller board (line loss is what I'm thinking)?

Actual theory behind LORs DC boards, they work like the AC versions, supplied with constant voltage (12v dc in this case) and the board raises/lower channel voltage for each item plugged into a channel?


TJ

[Steven]

TJ Hvasta wrote:

Actual theory behind LORs DC boards, they work like the AC versions, supplied with constant voltage (12v dc in this case) and the board raises/lower channel voltage for each item plugged into a channel?

The AC boards use triacs, which turn on at some point in the AC cycle, and turn off when the current reaches 0, which happens 120 times per second (in the US). The brightness depends on how early in the AC cycle they turn on. This is how an AC lamp dimmer works. The AC boards have a "zero crossing detector", which tells the micro controller when the voltage (and thus current, for most lights) reaches 0, so it can set the "on" time for the appropriate brightness.

The DC boards cannot use triacs, because the current would never reach 0. Instead it uses switching transistors (I'm not sure if they're FET or BJT). These transistors switch the voltage (usually 12V), on and off very fast (faster than 120Hz, but I don't know the exact frequency). It controls the brightness by changing the duty cycle, which is the percentage of time the transistors are on.

The big advantage for LEDs is that different LEDs respond differently to varying voltages, which is what AC is. With switched DC, the LEDs are either on or off, but they respond so fast that the brightness can easily be controlled with the duty cycle.

[TJ Hvasta]

Thanks Steve, my LED theory learning curve is a vertical line.. AC, no problem, DC/LED is too new for me to even hear what not to do

teege

[Guest guest]

Steven wrote:

TJ Hvasta wrote:

Actual theory behind LORs DC boards, they work like the AC versions, supplied with constant voltage (12v dc in this case) and the board raises/lower channel voltage for each item plugged into a channel?

The DC boards cannot use triacs, because the current would never reach 0. Instead it uses switching transistors (I'm not sure if they're FET or BJT).

My recollection is mosfets...

[Guest guest]

TJ Hvasta wrote:

Don, did you say you're running yours from a bench supply or a radio supply? I figure that both the Astron and Midland supplys are well-enough regulated to provide a clean source of DC. How long is the line from your supply to the controller board (line loss is what I'm thinking)?

I fired up my DC board from my bench supply, but will be using a 12V/20A switching supply I found on ebay...

I've been "dark" from a ham standpoint for 20+ years, so no supplies there to press into action...

For my design, supply and controller will be in same enclosure...

[Guest wbottomley]

gizmomkr wrote:

I just put my first one together, and was testing with some 12v plug-in type transformers. That worked great, but when I tried to dim them, I realized ALL the 12v plugs I have have a regulator.

Im thinking I can just pick up some 12v transformers without rectifier's - I didnt see any reson the board wouldnt run off AC v.s. DC. Anyone else tried that ?

Hey... I say try it.

But, don't come crying to momma that you got hurt and everything went up in smoke.

You have to use a DC card with a power supply or an IDMX and the Rainbow controller.

Pretty easy in my book as I'm using two DC cards and one power supply.

[TJ Hvasta]

Well, I have my 4 boards built and in their enclosures.. my LOR 16QC board wont show up for a while, I actually missed the line that they wont be available until late Aug.. I wudda gone with the term-strip version.. not sure why the QC will take so long if its just the terminals changing...anyway..

I changed out the cabling when I mounted the boards. The RF wouldn't fit in the case (well, the smaller yellow case) with the RJ45 jacks, so I soldered the Cat5 cable directly to the boards. I just have to figure how to run the 12vdc into the one end of the cat5 now. I may have to build an adapter board, with the RJ45 for the cat5 from the RF on one end, and a 3-pair tele cable going out with spade lugs on the other end to plug into the 16QC. The Odd pins (Cat5) were the B+, and the evens were Gnd, got that.. I think any other RF's I build from now on will have tel twisted pairs for power/control, 'gives me a longer run available (not running DMX).

[Randy]

Here's what I've ordered to use to connect the RJ45 cables coming back from the Rainbow Floods to the LOR DC board...

http://www.monoprice.com/products/search.asp?keyword=1152

These adapters are 65 cents each, and they will do the job beautifully. The picture on the Monoprice site may throw you, however. It looks like a db9 connector on the other end of the RJ45, but the great thing is that the connectors ship with the wires hanging out of the RJ45 portion of the connector. There are metal pins crimped on the end of the wires and they are ready to slide into the db9 connector, but it hasn't been done yet, depending on what your wiring convention will be for the db9 connector. No problem, just don't use the db9 connector. See my photo attached...

Instead take adantage of the metal pins on the end of the wires and put those into the screw terminals on the LOR DC board. You'll only need to connect 6 out of the 8 wires....Not a bad price for connecting your Rainbow Floods to the LOR boards!!!!

Randy


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