Star Trek in the age of LED's

[sengsational]

I was given this one one Christmas, and am interested in this thread as I've changed to LED lights on the tree, and it would be nice to light up the ornament.

That looks like the "NCC 1701-D". They made quite a few that are powered by "watch batteries", and those only light up when you press the button. I have the original NCC 1701 (no bloody letter), which was the first S/T ornament produced. It has LED lights (back in 1991 when LED's weren't so ubiquitous) that blink Morse code for "Merry Christmas".

 

[ERD50]

.... As suggested, I got an incandescent string (50 per circuit) plugged in and working, then swapped in a bunch of ornaments, one at a time and measured the voltage drop across the device. ... The lowest one was 5.8v and the highest one 13.6v*. I tried the rig I'd cobbled together based on my original assumption and it didn't operate even the least "needy" 5.8v device. So it's back to the drawing board.

...

Alright! Now we have some information to work with! No more shooting in the dark.

I assume those were all AC measurements? That could still make the readings a little tricky, the rectifiers in at least some of those ornaments could give a 'funny' reading.

But that's OK. I'll do a few calculations later, but I think it's still going to come down to the basic idea of using a higher voltage, with current limiting. I think your best bet is going to end up to be using the 24VAC transformer, with some sort of current limit for each ornament, a resistor or a light bulb.

Let me ponder it a bit.

-ERD50

 

[sengsational]

Some of the comments in this thread do seem to be pointing to the source as being current limited (as the bulb string would be), rather than just a fixed voltage.

https://electronics.stackexchange.c...a-new-power-source-for-light-string-ornaments

-ERD50

After going down this rabbit hole on stack exchange, and seeing how many people have tried all kinds of fancy and not so fancy things to get these ornaments working (and melting), I'm thinking I'll just lay out an old incandescent string and replace bulbs (up to the max recommended number) for ornaments. All the while, I'll monitor the voltage across each. Then, I'll start replacing some bulbs with a short circuit plug if the voltage gets too low, and add more ornaments. The result will be an incandescent string (or two) with my magic ornaments. I can cover the remaining bulbs with shrink tubing or something (the LED's on the tree are flexible, sometimes all white, sometimes colored, etc), so I don't want conflicting lights. And at the end of the season, I'll won't do any disassembly...I'll pack the whole works in one box so I can plug it in next year.


This is more work than I bargained for!

 

[ERD50]

After going down this rabbit hole on stack exchange, and seeing how many people have tried all kinds of fancy and not so fancy things to get these ornaments working (and melting), I'm thinking I'll just lay out an old incandescent string and replace bulbs (up to the max recommended number) for ornaments. All the while, I'll monitor the voltage across each. Then, I'll start replacing some bulbs with a short circuit plug if the voltage gets too low, and add more ornaments. The result will be an incandescent string (or two) with my magic ornaments. I can cover the remaining bulbs with shrink tubing or something (the LED's on the tree are flexible, sometimes all white, sometimes colored, etc), so I don't want conflicting lights. And at the end of the season, I'll won't do any disassembly...I'll pack the whole works in one box so I can plug it in next year.


This is more work than I bargained for!

That sounds reasonable. Each 5.8V ornament would replace ~ 2~3 bulbs with shorts, the 9V ones ~ 3~4 bulbs, and the 13.6V one ~ 5~6 bulbs.

How many ornaments total? I might not want to put too many on each string, no real feel for how many is 'too many', but offhand, to keep things from getting too far from nominal, maybe only 1/3rd of the string voltage for the ornaments total? So 120/3 = 40V, so about four of the 8~9V ornaments per string.

That's erring on the safe side I think. But as you eliminate bulbs, at some point you are sort of changing the characteristics of the power source. But I think you'd be fine replacing no more than about 20 of the 50 bulbs. I think that the remaining 30 bulbs will leave the voltage/current characteristics close enough.

It's also possible that, because some of the ornaments have rectifiers in them, they may not pass a full AC current through them (the bulbs don't care), so connecting ornaments in series may still be a bit 'iffy'.

The surest and easiest is to get the 20 bulb strings, and use one string per ornament (as nature intended!) . But experimenting with some in series on the 50 bulb string will probably work just fine.

Let us know!


-ERD50

 

[sengsational]

I started my project. Simple and inexpensive approach: add ornament, insert shorted "bulbs" until the voltage comes back up on a regular bulb to where it was with no ornaments plugged in (2.1v). Repeat. I've been shorting 5 between each ornament, which leaves plenty of room for ornament placement...next year (not going on the tree this year because it's too late).



Also, I replaced the capacitor in the Guardian of Forever, and it works now, but only after it warms up for a few minutes.

 

[ERD50]

I started my project. Simple and inexpensive approach: add ornament, insert shorted "bulbs" until the voltage comes back up on a regular bulb to where it was with no ornaments plugged in (2.1v). Repeat. I've been shorting 5 between each ornament, which leaves plenty of room for ornament placement...next year (not going on the tree this year because it's too late).



Also, I replaced the capacitor in the Guardian of Forever, and it works now, but only after it warms up for a few minutes.

Glad you found a solution and updated us (I almost forgot about this thread!)

Just to be extra cautious, how many ornaments total, I couldn't really tell from your picture? And are all the ornaments on a 50 bulb segment, or are they split across (what looks like) two 50 bulb strings in a 100 bulb string, or something else?

So what I'm looking for is - how many bulbs in a string originally, how many ornaments in that string and how many bulbs did you replace with a shorted bulb (the 1st # minus shorted bulbs plus ornaments should be how many bulbs are lit)?

I ask, because as I mentioned earlier, as you replace bulbs you are changing the characteristics of the power source that the ornaments 'see'. More specifically, the power source starts looking more like a voltage source than a current source. I can't really say at what point it might be a problem, but as I mentioned earlier, my gut says replace no more than 1/3rd of the bulbs in a string with shorts/ornaments.

As far as the " Guardian of Forever," needing to warm up, I have no clue, but if it's working at that point, sure, just go with the flow (or the force? Wait, that's Star Wars right? I'm not really into either of them).

-ERD50

 

[sengsational]

I have no problem mixing "the force" into trek. The older I get, the less I *know".


As I added ornaments, I monitored the voltage drop across one bulb. Without any changes, it was about 2.1v. I'd add an ornament, and it would drop to maybe 1.7v, and the I'd put in a few shorts. Very predictable. I added them, newest to oldest. Starting out, it took 4 or 5 shorts, then it started taking fewer to get up to 2.0v.


Everything went well until the Klingons. It went nuts. My test bulb went to 5.8v and I quickly switched off, but one of my bulbs blew. It's the only ornament that seemed whacky to that guy you pointed me to earlier in this thread. So I decided to segregate the Klingons, as politically incorrect as that might be. So all Hallmark wired ornaments from 1991 through 2005 are all on a 50 bulb circuit with 2 bulbs. Except the dang Klingons. They are on their own circuit, along with 49 bulbs. Merry Christmas to all, and to all, a good night.

 

[JBTX]

This is what happens when I try to play electrician.

https://youtu.be/RSWYi9fD_cE?si=tEkdiVyAgsh03oUP

 

[GrayHare]

Nice project, thanks for the updates. About Klingons, don't put them on the same string as Tribbles!

 

[sengsational]

Just to wrap-up this thread, I figured I'd share all the details

The video is over seven minutes, so probably not worth anyone's time to watch, but I figured it was worth publishing because, although there are several other options for powering these ornaments, none that I saw was as simple and cheap as my approach It shows how I stepped through getting all the ornaments powered from the 120VAC Christmas tree light string.

These still haven't been put on a tree...that will have to wait until next year. I plan on laying out the string, plugging them all in (I labeled the sockets), and hopefully they'll all work. They all worked when I put them away. I don't want the nightmare of adding the string to the tree and then (because they're serially connected) having none of them work. So much easier to find a problem if the string is laid out in a line. 14 ornaments plus 2 bulbs are on one circuit, and 49 bulbs and 1 ornament are on the other circuit.

 

[pacergal]

Thank you for doing the follow up video, I was interested in seeing all of your ornaments,
Hope they all work for you next year, looks like a fun tree in the future!