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.

pbryan

Members
  • Content Count

    39
  • Joined

  • Last visited

Community Reputation

0 Neutral

About pbryan

  • Rank
    Member

Profile Information

  • Location
    Belleville, MI
  1. My 2008 Display came down today... In an attempt to get this thread back on track, Here are a few more observations about the 2009 Samples. Overall, I'm pretty happy with their performance. Of the 36 2008 50 ct. strings I used, 6 times I encountered problems with outages. 4 times I had to check each LED, and eventually found one needing re-seating to re-light the string. Twice the problem corrected itself(!), both times in rainy situations (which bothers me more than the ones I had to fix!). Of the 9 strings of 2009 samples I used (4 from the first batch, 5 from the 2nd) I had none of these problems. The 2008 strings definitely caused some interference with my LOR setup. All the 2008 stings in my setup were 50ct., I ended up stringing them in pairs of 2, each pair of two was on a separate LOR channel. When dimming the 2008 LED's I would get some triggering of other LOR channels. This resulted in very short flashes of other LED strings, but was worse with some of the incandescent strings which would be on at a low intensity for a short time. With the 2009 strings I had 100 ct. strings paired in 2's, so 200 LEDs on each LOR channel. When dimming the 2009 strings I perceived no interference on other LOR channels. When dimming the 2008 50ct. strings on LOR, the rectifier "Blobs" would emit an audible buzzing noise. This did not occur with the 2009 strings. I did have a few issues with the 2009 samples... With one of the 2009 sample strings I found an LED making intermittent contact, after removing it I found that one of the contacts in the socket was crushed. The leads on the LED were bent as well, likely from inserting them into the damaged socket. Not too surprising from a low cost mass production operation, I noticed similar issues on some of my 2008 strings. The sample strings did not come with any extra LED's. This made it difficult in repairing the damaged LED noted above. I assume this is just because they were samples? And most importantly, I noticed while putting things away today that there was rust/corrosion noticeable on some of the 2009 LEDs. It was visible inside the base of the plastic lenses on about 10%-20% of the LED's. Was there a weatherproofing step not done because they were samples? or will this be a problem for the real production strings as well? --Paul
  2. So far so good with the new 100ct. strings... Since all my LOR equipment is now employed outside in my display, it's been a little more difficult to test the new strings. I just added the new 100 ct. ones to my display. The green still has a little fade out when it's power is cut but it's much faster than before. To my eyes, maybe twice as fast. Plugging the 50 count greens into the wall, they appear to be basically instant off. I haven't been able to play with them on the LOR setup yet, because I haven't really figured out how to incorporate them into my display yet... I've only been able to use one of the 50 count strings so far, the whites. Colorwise they look identical to the 100's. I have the 1st sample white 100's, 2nd sample white 100's and the white 50's all end to end on a tree. The biggest thing I notice is the 50's fade up and down faster and turn on and off faster. Based on just plugging the green 50's into the wall, I imagine they will also fade differently than the 100's. The different fade properties between the 100's and 50's isn't necessarily a problem, but it should be noted, and may drive people to use only 50's or only 100's in their display. I would be disappointed if I bought some 100's and some 50's to use together and then found they fade at different rates. I haven't been able to check the reported color difference in the greens. As a final note, so far all the samples have been holding up fine to rain, freezing rain, and now snow. --Paul
  3. For those of you interested in seeing the fading and on/off performance for yourself, I made a little video of the samples vs. some 2008 50ct. M5's and a 50 ct. clear mini string. The camera can't pickup all the subtleties but does a good enough job to see the major differences from string to string, color to color. Video is here: (Warning it's about 4.5 MB) http://www.paulbryanphoto.com/temp/CDI_LED.wmv --Paul
  4. Looks like a translation from (I assume) Chinese. I think what he's saying here is that a standard bridge rectifier requires a current limiting resistor in series with the LED's inside of each rectifier block. Since we're working with 120V AC, that resistor, in many cases, would have to dissipate a lot of power. In the case of the 50 count red's that some were converting to bridge rectifiers a 3W resistor was needed. That resistor will also get hot (or at least warm). Heat is bad for preventing moisture build up, and likely bad for passing UL (or other fire prevention) certifications. Their design using the capacitors creates a current limited power supply, with enough voltage to drive 100 LED's in one string. And since it doesn't need a big limiting resistor, it doesn't get hot. It sounds like from the other e-mail, they are pretty set in their component selection. It would be nice if they could tweak it a little to speed up that decay rate (especially for the greens). But it may not be as easy as we make it sound... --Paul
  5. You'll also be adding more parasitic power usage to the string of efficient LEDs. It's not a ton more, but part of the reason for using LEDs is power savings, and part of the design should always be to minimize power usage. Too much power dissipation here causes heat as well, which isn't usually good for encasement in a waterproof housing. Reducing the size of the caps could help too, but it will change the dynamic of the circuit in it's normal operation. There is likely a trade-off here between the power off decay rate and characteristics that give us the smooth fade up/down operation. It's possible that this hasn't been optimized. It's also possible that any further reduction in the decay time really hurts the fade performance. --Paul
  6. OK, so I've done some testing with the LOR setup now... I have to say, I think I like the new strings... The extra capacitance (in the colors other than red), give them a little bit of a incandescent feel. I can see where animated users (such as me) using both LEDs and incandescents would like that. The effect is a little exaggerated however, as it takes a few seconds for complete darkness when you go from 100% to 0%. The greens seem to take the longest, producing some amount of visible light for almost 4 seconds. All the fades seem to be very smooth, I'm not noticing any "hiccups" like I've seen in some of the '08 strings I have. I also don't get any of the audible buzzing I experienced when fading the '08 50-ct strings I have. My biggest complaint is the instant off of the red vs. the other colors. I'd like to see either the red's fade out a little, or the other colors instantly turn off. Perhaps a little shorter discharge time would be nice too, something closer to a incandescent mini-light. But if that came at the expense of smooth fades, then I can live with the longer time. I'll probably try to incorporate these strings in to my display this year and give them a bit more of a workout, but I don't expect any problems. So far I give them an A-. Get those power-off fade rates a little closer from color to color and that grade will go up. Again, it's not a "deal-breaker", but would be a "nice to have". Paul S. - Should we be concerned about the sample nature of these strings when it comes to using them outside? I'm sure they are fused properly so I'm not worried about my equipment, I just don't want to report a failure for a moisture (water/snow/ice) problem if they aren't intended to handle those conditions... --Paul
  7. True. Probably cheaper than running 4 wires, but still more expensive than the current approach. --Paul
  8. Looks about right to me... I haven't torn open a 2009 string yet, but this is the same basic circuit as the 2008's. With a few differences. In the 08's R4 did not exist, it was shorted. There were also additional diodes on the outputs of the rectifier blobs, would have been just before R3 and just after R4. These seemed to be pointless to me in the '08 strings as they were in the rectified side of the circuit, they should never have been needed, and it appears they have now been removed. --Paul
  9. #1) First, My experience with 2008 strings is only the 50-count M5 Red, Green, & Blue strings. I have not used any other color, count, or size. The only part failing in the 2008 Red 50-ct M5's was a small surface mount resistor on the output of the male plug end of the voltage doubler circuit. If you look at Bob V's schematic (which is very close to the 2008 schematic) it would be R3. It appeared to be an 1/8 watt resistor. Replacing that resistor with the same value, higher wattage, prevented failure. I'm not 100% convinced that the overall component sizing (both power and resistor/capacitor value) was perfect for those strings. In a few tests, replacing the blown resistor with one of equal value, but higher power rating (1/4 watt) didn't result in very smooth fades. In my repairs I ended up going with a larger value resistor (330 Ohms) in that location, because I felt that it gave smoother fades. I've tried as high as 1k Ohms no performance degradation, but that is likely because the voltage doubler circuit provides more than enough voltage for 50 2V LEDs. At some point you have to worry about power dissipation as well. So in short, yes the larger power rated resistor should prevent the same failure as witnessed in the 50ct. M5's. 2.) I haven't torn one open, but that appears to be true. 3.) A load on the female plug won't help. The female plug's outputs are simply 120AC line voltage run through the 2 wires in the string that don't attach to the LEDs. The voltage doubler circuit is split in half and takes the 120AC input at both ends, and supplies ~340V across the entire string of LEDs. To affect the discharging of the caps, you'd have to modify the circuits inside the plugs. Either reduce the capacitance or use a lower resistance bleed resistor. Both of these could impact how the circuit works in normal use as well. --Paul
  10. My strings came Wednesday. However so did my first child (2 weeks early!) so my test time will be a little sporadic for a while. I did plug the strings in and noticed the same thing everybody else is reporting, a significant fade off in all but the red strings. I haven't put them on my LOR setup yet, but it doesn't bode well for the red fading the same as the other colors. As for the capacitors, in the 100 count strings, if you want a series string of 100 LEDs you have to use capacitors. The 3+ volt drop of the non-red colors requires 300+ volts across the 100 count string. The 2 volt drop of the reds requires 200V. The only way to achieve that is with voltage multiplication circuits, and the only way to do that that I'm aware of is with capacitors. Looking at the circuit board that was posted, It looks like a voltage doubler, basically the same circuit as last years lights without the extra set of diodes (which were pretty pointless anyway). Here's the basic circuit: http://www.coolcircuit.com/circuit/voltage/vd.GIF The actual implementation has a bleed resistor across the cap (so it discharges when unplugged) and what looks like a resistor on the input and output. The input resistor will soften the inrush to the cap when it's charging. This helps with the noise put back on the AC side. I had to add this to the refits I did for this year 50 ct. reds. AT certain fade levels, the noise they were putting out was enough to trigger the triacs on other circuits on my LOR causing other strings of LEDs to flicker, and incandescents to glow dimly. The input resistor (only 2 ohms) took care of this problem. They could eliminate the capacitors if they went with smaller numbers of LEDs in parallel strings. Say 4 strings of 25. Of course this would require 4 times the amount of wire in each string, much costlier than a few 20 cent caps. Lastly, I'm a little concerned that there aren't any 50 count strings to be tested (especially red) or even smaller count strings since they produced the most problems this year. I'll post more as I get a chance to really play with them... --Paul
  11. For 100 light strings you will either need to reconstruct the voltage doubling rectifier or break the string into 2 (or more) parallel strings of 50 (or less) LEDs. Even the Reds with their 2V forward drop require 200V across 100 LEDs. You can't get that with a simple bridge rectifier and 120V AC. --Paul
  12. Any time you are dissipating 2+ watts through a resistor it's going to get a little warm... Too hot to touch starts getting into territory where you need to worry about resistors failing and worse, melting or even igniting things that come into contact with it. Sounds like you're on the right track. Work your way from dim to bright and stop just when you get there. Bumping the current up a few mA past it's ideal value may not give you a noticeable increase in brightness, but could degrade the life of the LEDs significantly. Working up on it from the dim side should allow you to find the point at which the brightness first matches. I'd think at that point you wouldn't be causing too much stress to the LEDs... --Paul
  13. 2 - 2W resistors will be the same as 1 4W in series or parallel. Just make sure you size the resistance right. 2 - 2W 4k's in parallel is like 1 - 4W 2k. In series it's like 1 - 4W 8k. --Paul
  14. I don't think I could choose without some testing... Got a Radio Shack (or similar) nearby? I'd want to see just how much the brightness is affected... If you can pick up a few diodes and resistors (or a potentiometer) locally you could do some testing. Putting 16-18mA through them might look just fine and you won't have to worry about anything. On the other hand, it might look too dim, in that case I'd want to see what resistance gave me acceptable brightness and work from there... The goal would be to find the lowest peak current with acceptable brightness. If you use a potentiometer, be careful, it will dial all the way down to 0 ohms. I'd get a 5-watt (or so) 10k pot, and make sure you stay to the high side, or you could kill the LEDs. Use an ohm-meter to make sure it's set where you want. BTW, the only fire danger would be from an undersized power resistor. Putting 2-watts through a 1/4-watt resistor will result in lots of heat after a short time. Over-current in the LEDs results in a very unspectacular death, they just turn off and never produce light again... --Paul
  15. As an example, here's a data sheet for a 5mm Red LED. NOTE: THESE ARE NOT THE LEDs USED IN YOUR STRING. http://www.superbrightleds.com/specs/r2_specs.htm These LEDs allow a Continuous Forward Current (If) of 20mA. This means you can run them at 20mA forever and they will meet all their performance and life specs. They also state a Peak Forward Current (Ifm or Ifmax) of 50mA. They also state conditions for the Ifm as 1/10th duty cycle, 0.1ms pulse width. This means you could run it without damage at 50mA for .1milliseconds if you allow it to rest with no current for .9milliseconds. They don't state any side effects of this, so I would assume the .1ms pulsing at 50mA would not degrade the life of the LED. Anything longer, or less rest time, likely would degrade life. Full wave Recitfied AC with a peak current of 50mA would far exceed their spec. But, with these LEDs I would guess that 30mA peak would likely be ok for a long time, probably not as long as keeping it under 20mA, but still acceptable. Without knowing the specs for our LED's we can only guess. Obviously, 18mA is safe. Some level above that should be acceptable in the pulsing, bridge rectified A/C situation. I just don't know how much more. --Paul
×
×
  • Create New...