Jump to content
Light-O-Rama Forums
Sign in to follow this  
Randy

A question about LOR and powering LEDs

Recommended Posts

I've been doing some experimentation with my LOR controllers trying to get smoother fades with LEDs. I have some Target LED Branch Trees, and also tested some CDI LED strings of 50 that have a flash when dimming at about the 50% level.

The Target trees flash 3 times and then go out when dimming at about the 50% level...

So, remembering from a thread last year about helping out LOR channels with light loads, I built up the device shown in the attached photo (C7 lamp in series with LOR Controller channel).

Sure enough, it smoothed up all the fades, on the CDI M5 50 ct blue LEDs, and even on the Target Branch trees. Smooth as silk. So now I guess I've got to build up a few of these to use in this year's display where the flickering is noticeable....

So, a question for LOR....Is there any way that the controller firmware can be modified to get the same behavior without having to add "the Doo-hickey"? I'm willing to build a few of these, but more than a few starts to take some time....The C7 bulb adds 5 watts when I'm trying to save energy with the LEDs....It'd be nice not to have to do this....

Anyways, I wanted to let folks know about this solution, but also wanted to see what the LOR folks might have to say about it....

Thanks, Randy


Attached files 160141=9306-LED Tree 1.JPG

Share this post


Link to post
Share on other sites

Randy, that is a good solution and should work well, but if you want an even simpler and cheaper solution that does not require the distraction of a white light coming on, then take a look at my alternative....
http://magiclightshow.com/bb/index.php?topic=41.0
I have a description and hi res photos there.

Also, this is not something that can be corrected in firmware. Triacs and SCRs need a small load to operate properly. You could add resistors to the channels in the LOR unit, but I advise against that so as to not risk a warranty issue if you screw up something. Besides, the trend is moving toward full-wave rectified LEDs and similar techniques that won't cause this issue with most LED strings. Only the cheap ones usually have this problem.


Edit: Oh and I forgot to say that the solution I use will need only a 1/2 watt resistor, not a 5 watt bulb.

Share this post


Link to post
Share on other sites

Thanks for the info, Richard. I was able to log into your site and check out the photos...I'll try to build some.....

Thanks very very much......Randy

Share this post


Link to post
Share on other sites

Richard, you provided good information, but I tried your tip exactly as you did, and it did not work,

Using a c9 bulb did work fine

Share this post


Link to post
Share on other sites

stachows wrote:

Richard, you provided good information, but I tried your tip exactly as you did, and it did not work,

Using a c9 bulb did work fine



Really! That is interesting. I am using about 15 of them on different channels of different controllers without issue. Are you sure that you used the right value of resistor? CrazyLady is also using this size of resistor in her thread, but she chose to solder and glue all that stuff together with modified extension cords.

Share this post


Link to post
Share on other sites

Yup... just got back from radio shack... 33K ohm, 1/2 watt resistors...

Tried 3 of them same results... They were REALLY cheap lights though... Thought if could use them with a terminator they would look OK.

Share this post


Link to post
Share on other sites

stachows wrote:

Yup... just got back from radio shack... 33K ohm, 1/2 watt resistors...

Tried 3 of them same results... They were REALLY cheap lights though... Thought if could use them with a terminator they would look OK.

Hmmm that is puzzling. I just called my colleague in Tennessee to ask if he had any trouble with his terminators and his are also working, but without the terminators, his lights are sporatic.

I would guess that your LEDs don't matter if they are cheap since you mentioned you got them to work with a C9 bulb. That result tells me that there is still not enough load on the circuit by using a 33K Ohm resistor. I did a little experiment just now and I am able to go as high as 45K before the lights start flickering again. Of course going lower on the resistor value will help, but it can't go too low or else a 1/2 watt resistor will get too hot. 33K will use .4 watts at 120 VAC. That should be enough to fool the Triacs into thinking a constant load is on the circuit.

Yea, I expect there to be some differences between the components in various manufactured controllers, but I would not expect there to be enough difference to cause this technique to work on some controllers, but not others. Just to be sure I understand what you did... You put the resistor ACROSS the AC line (like inside of a housing) instead of putting it in series with the lights? Right? It will be interesting to hear of other people's experience and comments.

Share this post


Link to post
Share on other sites

Richard, here is what i did to test your method....
Also, i put the terminator at the end... Used to playing with SCSI terminators...

Should it be before the lights? I would test it, but my halloween show is now runnigng for the night.



Attached files 160197=9309-PICT0035.jpg

Share this post


Link to post
Share on other sites

stachows wrote:

Should it be before the lights? I would test it, but my halloween show is now runnigng for the night.


Bingo, that is your problem. Remember that the LEDs you are trying to fix are likely half-wave rectified. That means when the AC current flows in the direction against the diode, then no current will flow and therefore the controller will not see a load.

By knowing what you do for a living, I know I don't need to tell you this, but for other folks testing like this, DONT KILL YOURSELF. There's 120 volts across the terminals of that resister. Of course, this is why I house it in one of those clam shells.

FYI... on rare occasions, I come across the clam shells that also have a female socket on the end. Those are best because they let you plug your lights into the clam shell without needing a 3-way adapter. This is something that the Randy thought about when making his light terminator. Bottom line is to put that resistor across the AC connection (in front of the LED string). Several kind of adapters are available for doing that. You could also use the one you have, cut the terminals short and epoxy cover the resister.

Share this post


Link to post
Share on other sites

That should do it... I will test, and then I will put the resistors in a safe enclosure...



Thanks for your help...!

Share this post


Link to post
Share on other sites

stachows wrote:

That should do it... I will test, and then I will put the resistors in a safe enclosure...

Thanks for your help...!

Let me toss in one last step. Even though I am very confident making things like this, and the clam shells are practically foolproof to make, I still use a voltmeter to test across the plug to make sure there is no short circuit before I use it. I would not want to be embarrassed to tell Dan that I blew out a controller channel !!!

Share this post


Link to post
Share on other sites

Richard, I completely understand....

If I blow out a controller I would just call Dan and blame you anyways!!!:shock:

Just kidding! Thanks again!

Scott

Share this post


Link to post
Share on other sites

What do you mean by plugging it in before the lights? It looks like if I plug the thing you made into the channel then there is no way for the light string to plug into. What am I missing?

Share this post


Link to post
Share on other sites

I think you can accomplish plugging in the device ahead of the lights because the end of the LED light string cord has a male plug and a female socket on the back side of the plug.

Controller --> Extension Cord --> LED Light plug into female end of extension cord & load device in female socket of LEDs --> Lights --> end of string

Share this post


Link to post
Share on other sites

JimCanfield wrote:

What do you mean by plugging it in before the lights? It looks like if I plug the thing you made into the channel then there is no way for the light string to plug into. What am I missing?

Hi Jim, that is what I mean in my earlier post. If you use a clam shell with a female connector on the other side, then you can plug the lights into that. Otherwise you have to use a 3-way female plug and no sense in spending an extra dollar for that too.

Share this post


Link to post
Share on other sites

Richard and all, just thought I would let you know that I retested my lights with the terminator BEFORE the lights, and the results were MUCH better. One string still had a VERY slight flicker around 50%, and the other was just fine.

Time to start making water proof terminators...

Thank you all for your input!!!

Scott.

Share this post


Link to post
Share on other sites

I see that now, sorry about that. I think I will look else where to fix my problem because I am not sure what is being said about the clam shell, and I know I am not good enough to wire something to the extention cord. The first idea seemed simple enough. Would the idea of plugging the plug protector into the back of the forst light string work as Randy explained?

Share this post


Link to post
Share on other sites

JimCanfield wrote:

Would the idea of plugging the plug protector into the back of the forst light string work as Randy explained?

Jim, if I understand your question correctly, the answer is no. Regardless of the technique you use, the device must be connected between the controller and the first light string to get it to work properly.

Share this post


Link to post
Share on other sites

JimCanfield wrote:

would it be possible to expound on the clam idea? If it is not to awful hard I may try it.


Jim, it is a LOT easier than you think. The clamshell already has two screw terminals in it. All that is needed is to attach a 33K Ohm 1/2 watt resistor to the terminals and close it up. The clamshell are available at Home Depot for about 80 cents and an pack of 5 resistors are Radio Shack are $1. I built 25 of them in about an hour.

The photos of the clamshell that you saw on my web site are not exactly the ones I use. I have the version that also has a female connection at one end and a male connection at the other end. This is to allow you to plug it into the LOR circuit and then plug a string of lights into the clamshell. These types of clamshells are harder to find. I'll see if I can locate some.

You picked up on the problem with using the type of clamshell that does not have a female socket on it. In that case you would also need a 3-way adapter and that just increases the cost by another dollar. The photo I posted was just to show the technique.

Share this post


Link to post
Share on other sites

Richard,

Thanks for the tip! I am having issues with some channels and this should solve it.

Let me know where you got the Male/Female clamshells.

THANKS!

Share this post


Link to post
Share on other sites

wirekat wrote:

Richard, Thanks for the tip! I am having issues with some channels and this should solve it. Let me know where you got the Male/Female clamshells. THANKS!


wirekat, I was looking for the male/female clamshell adapters at Home Depot last night. I did not see any. I made these 2 years ago, but surely they should be around. I will look online today and come back to post if I find them. I originally got them at Home Depot.

Alternately, I think Randy's solution is a good one as I mentioned earlier. From the photo, it appears he used the slide-on AC plug, AC socket, and C7 socket that are readily available at many places online. They easily slide onto SPT1 wire that you can get at any hardware store. Thus, no tools needs. Is that what you did Randy?

Yea, it is a little bit more expensive, but a safe solution also. The only downside as he mentions is burning 7 watts for no reason. And if you have to do that on 16 channels, there goes 110 watts in the air. I also estimate the cost per channel is about 50 cents AC plug, 50 cents AC socket, 50 cents C7 socket, 10 cents wire, and 75 cents for the C7 bulb... so that is $2.35 per channel to correct LEDs.

Bottom line, I suggest that using any of these methods, Randy's, mine, or others is probably a good idea only if you are trying to salvage a bunch of older LED strings (like you said) that you already have. For new strings, its actually cheaper to just buy the better quality full-wave rectified LEDs that have no perceivabe flicker, and in my experienced, every string of full-wave rectified LEDs don't have a problem fading.

And keep in mind that it only takes about 1/2 to 3/4 watt of load on a channel to allow for smooth fading of LEDs, so if you can find lower wattage incandescent bulbs or use a resistor, you will waste much less energy on multiple channels.

Share this post


Link to post
Share on other sites

Spounds like a good easy solution Richard, thank you. Herein lies my problem. You mnentioned quite a few times that this is only needed for the older LEDS and not the full-wave rectified LEDs. I purchased a case each of Red, Green, Blue, and Yellow 5MM LED from Paul. I was playing with 1 string of 35 count blue and it had a severe flicked in fading. When I plugged a strand of minis to it the flicker was corrected. Could it be that it is because it was only 1 strand of 35, therefore there was not enough for the triacs? If so that just means I should plug 3, 4, or 5 end to end and see if that helps. I appreciate you helping out like this. I am not planning on using just 1 strand, so it may be that I do not need any of these.

Share this post


Link to post
Share on other sites

JimCanfield wrote:

I was playing with 1 string of 35 count blue and it had a severe flicked in fading. When I plugged a strand of minis to it the flicker was corrected. Could it be that it is because it was only 1 strand of 35, therefore there was not enough for the triacs? If so that just means I should plug 3, 4, or 5 end to end and see if that helps. I appreciate you helping out like this. I am not planning on using just 1 strand, so it may be that I do not need any of these.


Jim, I really doubt that plugging more led strings into the same channel will solve the problem. A typical led string of 35 bulbs should draw at least 5 watts, so it is not a problem that the leds draw so little current that the triacs aren't fading smoothly. It's likely the fact that they are half-wave rectified leds so when the AC current switches to power the LEDS in the direction opposite of the diodes, no current will flow during that 1/2 cycle and hence the triacs see no load.

When you plugged in the mini lights, that kept a constant small load across the circuit. This is the best and easiest solution to the problem. When I have a string of old LEDs that flicker, I sometimes add in a string of mini lights of the same color to give it a load. It depends on where I am using the LEDs. I light the lights to look all the same. Just be sure that the incandescant light are plugged into the controller first.

Share this post


Link to post
Share on other sites

Yes, I built up my adapter from SPT2 wire and vampire plugs from Action Lighting with a 5 watt C7 bulb.

I did this because of the LED Branch trees I bought at Target this year, but also because of the Full-wave CDI LEDs that I purchased this year.

On the CDI LEDs, what I've noticed from testing is that the strings of 100 of either C6 or M5 seem to fade okay. It's when I get less on one string (50 and 70 for me) that I'm having fading issues. I spent a lot of $$$ for those LEDs, and even though Paul has made the offer to take them back after the season, I have to disassemble them and pay for return shipping. I haven't decided what to do on that front....

Interestingly enough, if I do connect two strings of 50 or 70 in series, the fades look okay, or if I connect a set of 100 LEDs at the end of the 50s or 70s. So there does seem to be an issue with the minimum load for the channel.

Unfortunately, I do have several channels where I have just one string of 50 or 70 on that channel, so these adapters were a way to try and "Rectify" that. I did order some 33K resistors from a seller on eBay, so those should in soon. If I can't find a clamshell, I'll try to put together something from my extra parts bin here to prevent from having to burn 5 watts on each channel....

Thanks for your help...

Randy

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

×
×
  • Create New...