Jump to content
Did you know?
  • The original Rudolph did not have a red nose. In that day and age, red noses were seen as an indicator of chronic alcoholism and Montgomery Ward didn’t want him to look like a drunkard. To complete the original picture, he was almost named Reginald or Rollo.
  • The Christmas wreath was originally hung as a symbol of Jesus. The holly represents his crown of thorns and the red berries the blood he shed.
  • The three traditional colors of most Christmas decorations are red, green and gold. Red symbolizes the blood of Christ, green symbolized life and rebirth, and gold represents light, royalty and wealth.
  • Tinsel was invented in 1610 in Germany and was once made of real silver.
  • The oldest artificial Christmas trees date back to the late 1800s and were made of green raffia (think grass hula skirts) or dyed goose feathers. Next the Addis Brush Company used their machinery that wove toilet brushes to create pine-like branches for artificial Christmas trees that were less flammable and could hold heavier decorations.
  • ‘Jingle Bells’ – the popular Christmas song was composed by James Pierpont in Massachusetts, America. It was, however, written for thanksgiving and not Christmas.
  • Coca-Cola was the first company that used Santa Claus during the winter season for promotion.
  • Hallmark introduced their first Christmas cards in 1915.
  • The first recorded date of Christmas being celebrated on December 25th was in 336, during the time of the Roman Emperor Constantine. A few years later, Pope Julius I officially declared that the birth of Jesus would be celebrated on that day.
  • Santa Claus's sleigh is led by eight reindeer: Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Dunder (variously spelled Donder and Donner), and Blixem (variously spelled Blixen and Blitzen), with Rudolph being a 20th-century inclusion.
  • Outdoor Christmas lights on homes evolved from decorating the traditional Christmas tree and house with candles during the Christmas season. Lighting the tree with small candles dates back to the 17th century and originated in Germany before spreading to Eastern Europe.
  • That big, jolly man in the red suit with a white beard didn’t always look that way. Prior to 1931, Santa was depicted as everything from a tall gaunt man to a spooky-looking elf. He has donned a bishop's robe and a Norse huntsman's animal skin. When Civil War cartoonist Thomas Nast drew Santa Claus for Harper's Weekly in 1862, Santa was a small elflike figure who supported the Union. Nast continued to draw Santa for 30 years, changing the color of his coat from tan to the red he’s known for today.
  • Christmas 2018 countdown has already begun. Will you be ready???
  • Why do we love Christmas? It's all about the traditions. In this chaotic world we can miss the "good old days." Christmas reminds us of that time.
cpnbnanamn

LED Circuit design question......

Recommended Posts

I've posted this same question over at RJ's forum, and to be honest, I'm stumped.... I'm hoping someone with a far better grip on electronics than I have, can help me out....

My first controlled display this year will be for Halloween. I have already started building controllers and props, etc, and I have one in particular that I want to add a pair of LED 'eyes' to, so that they can be controlled by one of the channels of a controller (You know, so that my character can 'sing' along?)

Problem I'm running into:

I know that LED's are supposed to be run from DC voltage, and I'm afraid that a wall-wart won't have the reaction time necessary to make this happen (because of capacitor charge/ discharge). Is this true? Am I thinking correctly on this? Does anyone have a circuit in mind that I could use in this respect?

Any help you guys could provide would be GREATLY appreciated. It would make my first display ROCK!

Thanks!

-Roger

Edited by cpnbnanamn
Misspelled title...

Share this post


Link to post
Share on other sites

Hi Roger and welcome to PC!!

May I suggest a more appropriate place to post this question - that would be in the Computerized Displays, Do-It-Yourself or Lights sub forums. Dashers Diner is fairly general and you might get a better answer in a sub forum more particular to your question.

Have fun and hope you find what you are looking for.

Share this post


Link to post
Share on other sites

You do NOT want to switch the input side of a transformer like that. Forgetting about the delay, that will QUICKLY destroy the transformer. Instead, you need to switch the OUTPUT side. If it's DC you want to control, then you need something that can switch DC - like a DC SSR, transistor, etc...

Assuming you are using DIY controllers, check http://doityourselfchristmas.com/. There are a couple of designs there (DC SSRs, REN48LSD) that can control DC.

Share this post


Link to post
Share on other sites

Craig,

Sorry... I wasn't quite sure where to put this, so I tried here first. Maybe I can get a moderator to move it for me.

Mike,

You know, that's the same answer I just got on DLA's site. I am using DIY (in the case, RJ's stuff), and he just piped up with the same type of answer. Thank you!

-Roger

Share this post


Link to post
Share on other sites

I would normally think controlling a wall wart with a 120V controller would be a bad idea as well, but some here claim they have done it with good success (including effects such as twinkle/shimmer/etc). In fact it's one of the ways that Greg (ponddude) lists in the manual for his Rainbow Floods/Wall Runners/etc.

Share this post


Link to post
Share on other sites

Switching a wall-wart on and off without destroying it depends on its design. If it is a simple transformer with a simple rectifier, then you can switch it on and off without much fear of damage. These aren't very efficient on a weight to amperage ratio, so they are kind of rare.

Wall-warts using Switching technology are more common. Higher efficiency means smaller components and less weight. But - they don't like their input voltage being switched on and off rapidly. Their electronics with overload. I have experience with this. :(

I'm afraid that a wall-wart won't have the reaction time necessary to make this happen (because of capacitor charge/ discharge). Is this true?

Your very first post shows that you are concerned about how the power supply will react to changing loads (reaction time). That should not be a problem.

So - leave the power supply (of whatever type) connected to 120VAC constantly (unswitched). Use a DC controller to turn the outputs on and off.

post-2895-129571228846_thumb.jpg

A last re-read of your whole post tells me that you are probably only running one or maybe two AC controllers. If you want to avoid the expense of a DC controller, then you will have to switch the power supply on and off. If so, I'll give you two tips:

1. Use a power supply / wall-wart that is heavy. It is more likely to have a beefy transformer and survive the transients.

2. Don't do any SHIMMERS!! Seriously. A shimmer command will kill it dead. ON and OFF only.

Share this post


Link to post
Share on other sites

Use a DC controller to turn the outputs on and off.

[ATTACH]35594[/ATTACH]

A last re-read of your whole post tells me that you are probably only running one or maybe two AC controllers. If you want to avoid the expense of a DC controller, then you will have to switch the power supply on and off. If so, I'll give you two tips:

1. Use a power supply / wall-wart that is heavy. It is more likely to have a beefy transformer and survive the transients.

2. Don't do any SHIMMERS!! Seriously. A shimmer command will kill it dead. ON and OFF only.

Thanks for the advise, Jon. I think what I've decided to do it run a DC controller in addition to the AC controllers I have. (Hopefully, by the time blinky season starts, I'll be up to at lease 64 channels.) But allow me to ask a question about the DC controllers. It doesn't appear that most DC controllers incorporate an AC input converted to DC and then switched. (And your picture kinda adds to that theory)... am I thinking correctly? I'm looking at getting a DMX16DCSSR or a MR16 to accomplish my task....

-Roger

Share this post


Link to post
Share on other sites

Roger, the DC controllers definitely use DC input only. They don't convert it from AC. While most DC controllers (D-Light or LOR) are run on either 12VDC or 24VDC, they can go up to 60VDC. Never found a use for that, though. I'm a 12VDC guy because I want to run from a Car Battery for portability. Of course, two car batteries will give you 24VDC. :)

Other power supplies can be used besides a battery. One choice is an old computer power supply. Not the easiest choice, but cheap if you have one lying around. They can supply a LOT of 12VDC current. Otherwise, shop on EBay for a 12VDC power brick. You can find them in 2 amp, 3 amp, 5 amp and higher ratings. A DC controller can easily handle 20 to 30 amps, though.

Your LED pumpkin eyes are definitely on the low end of the power scale. For the DC portion of my halloween display this year, I'll be running a bunch of 12V Ultraviolet (Black Light) LED clusters. I bought 6 of them already but will need more, I think.

They look like this: http://www.sureelectronics.net/goods.php?id=242 except that there are 24 instead of just 8, but still just need 12VDC and need very little current. Things really do glow like any Black Light would.

Share this post


Link to post
Share on other sites

I would normally think controlling a wall wart with a 120V controller would be a bad idea as well, but some here claim they have done it with good success (including effects such as twinkle/shimmer/etc). In fact it's one of the ways that Greg (ponddude) lists in the manual for his Rainbow Floods/Wall Runners/etc.

You are correct Tim.

I'm one of those that claim using wal-warts to power my LED stuff. People say not to use them and I wonder where they get their info unless they experienced themselves.

I've been using wal-warts for years now with no problems AND using the twinkle/shimmer/fading modes. Again, with NO problems.

MR16LEDs

Greg's RWR

Chavet LED strobe

Flex LED strips

All of these I have are powered thru wal-warts with no failure to the LEDs or controllers (LOR).

Hope this helps.

Share this post


Link to post
Share on other sites

You are correct Tim.

I'm one of those that claim using wal-warts to power my LED stuff. People say not to use them and I wonder where they get their info unless they experienced themselves.

I've been using wal-warts for years now with no problems AND using the twinkle/shimmer/fading modes. Again, with NO problems.

MR16LEDs

Greg's RWR

Chavet LED strobe

Flex LED strips

All of these I have are powered thru wal-warts with no failure to the LEDs or controllers (LOR).

Hope this helps.

I destroyed the transformer in a Snow Flurries (12V), when I accidentally got the channel into a group in AD that was doing a shimmer. It took 1 night.

Edit: Actually, I destroyed it in Vixen last year when I incorrectly converted the channel from an old AD routine. Same thing though, it was a shimmer and I killed it.

Edited by oldcqr

Share this post


Link to post
Share on other sites

I also killed a Snow Flurries with a shimmer. I immediately cut out that transformer and wired in another one that has survived a few accidental shimmers. I'm not testing it with a long-term shimmer, though.

Share this post


Link to post
Share on other sites

I also killed a Snow Flurries with a shimmer. I immediately cut out that transformer and wired in another one that has survived a few accidental shimmers. I'm not testing it with a long-term shimmer, though.

Out of curiosity, were you controlling the input to the wall-wort, or the output? I can see killing it if you put it on the output side of an AC controller and doing the shimmer, but I would think you'd be OK if it were a DC controller with the wall-wort providing the input voltage.

Hey Roger.....

Since you're getting a 16 channel controller and said you wanted to control two eyes, go RGB LED's in them. That way you'll be able to do different colors - various shades of red, purple/violet, orange, green.......

And yeah, I'm the Jack he blames......

Share this post


Link to post
Share on other sites

Input. Plugged it into a controller just like a normal set of AC lights.

What you are describing, using a transformer to power a DC board and then having that board do a shimmer on a DC channel, is the way most people agree it should be done. Others have stated that some wall warts will handle shimmers just fine, depending on how they are built. Tom then tried to discount the warnings posted by saying that no one had experienced a failure based on the warnings. 2 of us have experienced 'rapid switching transformer death'.

Share this post


Link to post
Share on other sites

I know several people have said that they destroyed a transformer. I’ve never got an answer of what was wrong with it. I even asked for someone to send me a failed transformer though I’ve never received one.

I’ve purposely tried to destroy one and have been totally unsuccessful. I’ve flashed and ramped for days and haven’t even got so much as even a buzz out of one.

The only thing that I can think of is that maybe the fuse opened up. Some transformers have internal fuses that are just slightly higher than their maximum rating. Some of these are easy to fix or remove and use an external fuse.

Someone once told me that you can’t drive an animated deer with a TRIAC type controller. I’ve been doing it for five years now and the only problem they’ve developed is a little rust. These get flash and ramped a lot during a show and then sit dimmed the rest of the night.

Share this post


Link to post
Share on other sites

The problem with my failed transformer was 0v output. There was no physical damage, or melting/burnt smell/etc. Voltage went in, nothing came out.

I've never heard the deer thing.

Share this post


Link to post
Share on other sites

Tom then tried to discount the warnings posted by saying that no one had experienced a failure based on the warnings.

Wait a minute. Which Tom are you referring to here?

Share this post


Link to post
Share on other sites

I know several people have said that they destroyed a transformer. I’ve never got an answer of what was wrong with it. I even asked for someone to send me a failed transformer though I’ve never received one.

I’ve purposely tried to destroy one and have been totally unsuccessful. I’ve flashed and ramped for days and haven’t even got so much as even a buzz out of one.

The only thing that I can think of is that maybe the fuse opened up. Some transformers have internal fuses that are just slightly higher than their maximum rating. Some of these are easy to fix or remove and use an external fuse.

Someone once told me that you can’t drive an animated deer with a TRIAC type controller. I’ve been doing it for five years now and the only problem they’ve developed is a little rust. These get flash and ramped a lot during a show and then sit dimmed the rest of the night.

I've thought about controlling the input of a wall wort with an AC controller, but for the most part, my stuff is outside and I didn't want to go through the trouble of sheltering the wall wort from the weather.

As to the deer, I generally unplug the motor part and run it separately. I didn't want any inductive kick-back from the start/stops to negatively impact my controllers, plus I prefer the smoother movement of letting it run, rather than the jerky movements I'd get from running it on a channel. I also think the erratic voltage/current feed would shorten the life of the motor, and encourage mechanical jams. I'm cheap; I use an AC timer for the motors and the static part of the display.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...