I have been using 3mm Red/Green two lead LED's for turnout indicators for a couple of years now and just added some new ones but they are at least 2x as bright as the others. I bought them all from All Electronics but at different times and I noticed this last batch that some are brighter than others. I want to know if I can put a small value resistor in line with the lead to the Tortise (on contact No 1) or will this affect the operation of the Tortise. I run my Tortise motors at 9 vdc.
Also, two of them are blinking red to green and the Tortise machine doesn't work. These worked fine before replacing the older LED with my new design. No other change was made?? Very baffling?? But only two of do this?
I have made a bunch of these LED switch lanterns and don't want to have to remake them with different LED's as it is a lot of tedious work (see photo).
-Bob
Life is what happens while you are making other plans!
With regard to your question about using a resistor in series with your LEDs, yes you can do that. The Tortoise may run a bit slower (or a lot slower if you use too much resistance). But you may not notice a lot of difference with the LED intensity. I finally resorted to diffused LEDs to lessen the intensity.
Regarding the blinking LEDs, is the blinking interval constant or random? If the former you may have received flashing or blinking LEDs. Try changing out one of them to a know OK LED and see if the blinking stops. If not, you have a wiring problem.
Have to be a pretty crazy wiring problem to make a normal red/green 2-wire LED flash back and forth - the only way for the color to change is for the polarity to reverse, so it would be like a low frequency AC is applied instead of DC. I suspect it's more likely that somehow they mixed in some sort of flashing LED. They actually do make such things, and since the leads connect to an internal IC and not just diodes, they won't work inline with a Tortoise the way an ordinary LED will.
Putting a resistor in series may help, but you'll probably need so much resistance that the Tortoise will be slowed too much. These new ones are probbaly high brightness or high efficiency LEDs and just are much brighter at the same current level than the old ones.
The lesson (which we never learn - I've done it plenty myself) is when using a different part number than previously used - test first with just one. I think you are pretty much out of luck with the assemblies you already made with these new LEDs.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
The newer LED's are the same part number so I guess they changed the part! I will try to use some kind of paint ( ?) To soften the brightness.
I didn't notice before but the two flashing ones are controlled by a Digitrax DS44 ? decoder so that may be where my problem lies!
I really don't want to have to remake them!
Thanks for your help and I will keep you posted on my resolution of this problem.
- Bob
If they are controlled by a DS64, maybe you ahve accidently set it to use the output as a grade crossing flasher instead of a Tortoise driver. That would make the polarity flip back and forth (it doesn't seem like that wouldbe the case, but the way they work internally is a little odd and definitely would make a bi-color LED flip back and forth).
rrinker If they are controlled by a DS64, maybe you ahve accidently set it to use the output as a grade crossing flasher instead of a Tortoise driver. That would make the polarity flip back and forth (it doesn't seem like that wouldbe the case, but the way they work internally is a little odd and definitely would make a bi-color LED flip back and forth). --Randy
Randy,
I feel a little silly here; I found that I had a short in the DCC rail (a turnout under construction) and it caused the blinking on those LED's. Don't know why I didn't notice it, although I was just flipping the power on and off to test the LED's as I installed each one??? Just one of those days.
I did try some white Testors PLA on one of the finished lanterns and it seems to have cut down the overly bright glare. I think it will work OK on them and when not powered the lens looks a little white; until I find some other 'coating' that will cut back the light. I was checking each LED as I installed it in the base casting and some are of the dimmer type (preferred to me)? They all came from All Electronics so it could be a manufacturing QC issue (in China I assume!).
Or it's the same All Electronics part number but sourced from a different manufacturer. Hey, no one will notice, plus they get brighter LEDs for the same current draw. Except when you DON'T want brighter LEDs.
All is sort of halfway between surplus and a dedicated retailer/wholesaler like Mouser or Digi-Key. So their stock can vary, but they are usually cheaper. A place like Mouser, they carry LEDs from a variety of manufacturers, and they list the specs. For things where it doesn;t matter, like a power light for a power supply or something, I just get the cheapest. But you can also pick by brightness, or color temp, or whatever, from each of the manufacturers. And get good repeatbility - you order the smae spec LED a year apart, they may vary slightly because of being different batches, but they will be close, within some specified tolerance, of each other, not widely different. But, you pay a bit more for the consistency.
Didn't think of that Randy, All does have varing product listings and some items are only available until their stock runs out, and some of their stuff is used, removed from working equipment. Just have to watch what I buy.
As far as the LED's go, there is quite a difference in the brightness. I will have to post a pic to show two next to each other, very different! If I can get the bright ones 'calmed down' a little more, they will actually look better than the older ones. Don't know what I will do then??
Thanks for all your comments and insight.
Here's a photo of the two LED's. I couldn't get a true image of the lights as the camera intensified the LED and almost made the centers look white, where as they are actually bright green.
Yeah, that's a completely different spec LED, HUGE difference. The bright one looks like someone set up a fusion reactor in there. The old ones look great. If you have a pair of spare wall warts with the same voltage, you could wire a set of Tortoise contacts and the two power supplies as a bipolar power supply, and use a resistor - start at 10K, probably work up, given how much brighter those are. If you have power supplies that are less than 12V, that will reduce the size of resistor you need.
Take the + of one and the - of the other and hook them together. This goes to one side of the LED. The other side of the LED goes to the wiper of one of the Tortoise switch contacts via a resistor. The free + of one power supply goes to one side of the contact, the free - of the other goes to the other side of the contact. Keep all the new LEDs in the same area so you don't have to string wires all over. You don;t need much power, even a 300ma supply will drive nearly 30 of them, depending on the resistor you end up with.
farrellaa
In brightest day, in blackest night,No evil shall escape my sight.Let those who worship evil's might,Beware my power... Green Lantern's Light!
Disclaimer: This post may contain humor, sarcasm, and/or flatulence.
Michael Mornard
Bringing the North Woods to South Dakota!
rrinker Yeah, that's a completely different spec LED, HUGE difference. The bright one looks like someone set up a fusion reactor in there. The old ones look great. If you have a pair of spare wall warts with the same voltage, you could wire a set of Tortoise contacts and the two power supplies as a bipolar power supply, and use a resistor - start at 10K, probably work up, given how much brighter those are. If you have power supplies that are less than 12V, that will reduce the size of resistor you need. Take the + of one and the - of the other and hook them together. This goes to one side of the LED. The other side of the LED goes to the wiper of one of the Tortoise switch contacts via a resistor. The free + of one power supply goes to one side of the contact, the free - of the other goes to the other side of the contact. Keep all the new LEDs in the same area so you don't have to string wires all over. You don;t need much power, even a 300ma supply will drive nearly 30 of them, depending on the resistor you end up with. --Randy
Thanks Randy, I knew there had to be a solution. I just happen to have two NIB 3VDC regulated wall warts which I planned to use to power LED's in my buildings and some panels. This would be a great sacrifice. I don't have all the new LED switch stands in the same area but I can run a few terminal strips to subdivide the wiring. They are basically in two general areas of the layout so I can put the power supplies near one group and then send a leader to a couple of terminal strips/power distribution type and feed the other group; if this makes sense to you? Great idea! Thanks again.
Bayfield Transfer Railway farrellaa In brightest day, in blackest night,No evil shall escape my sight.Let those who worship evil's might,Beware my power... Green Lantern's Light!
Great comback Michael! And I have all those conditions covered! Many times!
Another option that would not slow down the Tortoise would be to add a resistor in parallel with the LED's to allow some of the current to bypass the LED.
YOU do not have to use a resistor if you put the LED in series with the Tortoise motor. Or with a relay for that matter.
BUT
LION never does that, him always use LED/Resistors in parallel with the turtle. Him can use three or more signals with every switch machine plus more on the panel.
LION uses a common HARD ground (never a floating common) all around the layout.There is ONE WIRE that controls the Tortoise, the signals any additional relays and panel lamps.
WIRE is expensive, use as little as possible.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
BroadwayLion YOU do not have to use a resistor if you put the LED in series with the Tortoise motor. Or with a relay for that matter. BUT LION never does that, him always use LED/Resistors in parallel with the turtle. Him can use three or more signals with every switch machine plus more on the panel. LION uses a common HARD ground (never a floating common) all around the layout.There is ONE WIRE that controls the Tortoise, the signals any additional relays and panel lamps. WIRE is expensive, use as little as possible. ROAR
Lion,
The LED's are in series with the Tortise, using contact No 1. This is how all my LED's are wired so they always show turnout position and without using a resistor. How do you wire a resistor in parallel, or where?
-Bob (PS: I believe I am supporting the wire industry!)
Correction to my LED source: It seems I got the newer ones from The LED-Switch Co, and not All Electronics as I had thought. Sorry for the error and for implying that the mfg or supplier may have changed the specs on it.
I have made several purchases from LED Switch and he has a very good selection of electrical components at reasonable prices, I noticed the same thing with the recent batch of LEDs I got from him about four months ago. They were considerably brighter than ones purchased years ago.
http://www.led-switch.com/
Here is a photo (just a grab shot) of a recent panel I'm working on using his "pure green" bi-color LED. I find the diffused LEDs to look nicer than the "water clear" variety in panel applications.
Like the condition you have, the green is very intense! I may feed this group with a lower voltage supply and see if that helps. I'm right around 12.2 V here.
One thing I do is use the yellow/red LED for secondary tracks and the green/red on the main.
Good Luck, Ed
farrellaaLion, The LED's are in series with the Tortise, using contact No 1. This is how all my LED's are wired so they always show turnout position and without using a resistor. How do you wire a resistor in parallel, or where?
Click on the images to enlarge and read da details. (de tail is at the other end of the cat.)
This is actually the power supply that I am using.:
I was thinking it, but I wasn't going to say it. My geek card is big enough.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!