Who makes some bright Head and ditch lights.The ditch lights also need to flash when i push one of the bottons on my controler. Im going to use a digitrax sound decoder.
Thanks
Colin
Great question, I’m glad you asked I was going to post this same question. I have a couple of Locos (HO DCC) whose headlights are very dim and was wondering how to make them brighter.
I use super-bright golden glow LEDs purchased from Litchfield Station. Other DCC suppliers such as Tony’s Train Exchange probably also have them. They cost $1.50 each, and come in both 3mm and 5mm sizes.
In order to have flashing ditch lights you have to have a decoder that supports that function. The Digitrax SoundFX decoder is a good choice because it has the ditch light function.
if you plan to put lights in a lot of locos or you can split the costs with other modellers buy some xmas lights with small bright white L E D 's for maybe 20 dollars you will get 160 leds plus cable plus transformer wait until after xmas even cheaper use shrink wrap to join the leds to the clear lighting and the shrink wrap ( black ) will also stop any stray light use a 680 ohm resister… this will give you very bright lights peter
Do you just put the LEDs in the same place the current light attaches (electrically)? Do you need to install a diode or a resistor of some sort? That’s where I get confused.
You can’t just put ANY resistor in line with an LED. You need to calculate the correct resistor value using a calculator like one of these: http://led.linear1.org/1led.wiz
Also, it’s possible to add the circuitry so the ditchlights are always on and when you turn the ditch light function on to have them flash…
Do you just put the LEDs in the same place the current light attaches (electrically)? Do you need to install a diode or a resistor of some sort? That’s where I get confused.
Yes you do need to protect your LED with a Diode and a suitable resistance. This is because they do not withstand reverse voltages well and will blow readily…there is no magic about it, just put your dropping resistor and your diode in series with your LED. Theago only issue you might have is if you have a sensitive motor and your loco takes off before your lights go on. If you are using DCC it is not so much of an issue. There was an article about this in the Australian Model Railway Magazine a little while ago about LED’s and circuit boards.
You can contact me offline if you need clarification xdford47@yahoo.com.au …
Regards
Trevor www.xdford.digitalzones.com FYI
I use 30 ma 1.5 volt incandesent bulbs from miniatronics with a 860 ohm resistor in them. They are very bright. I mount them in the light sockets of the locomotives with silicone. Here’s a picture of the lights. The ditch lights in the photo are also scratch built with styrene. (Click to enlarge.) You’ll need a good multi-function decoder if you want the lights to flash.
I usually use 680 ohm resistors with mine…put the resistor on the longer of the two legs, this is your + (positive) side, the shorter side will go to your decoder’s - (ground). If you get it in backwards nothing will happen, it just won’t come on and you’ll need to flip it around. There is no need for a diode as an LED is a diode (Light Emitting Diode) and a diode provides negligible resistance (ideally the resistance would be zero) in this case, but will result in roughly a .7V drop, making your light dimmer.
Actually, reversing the polarity through an LED can cause them to release the magic smoke. This becomes especially true with some of the LED’s that change color, or have the ability to make multiple colors through the use of multiple + or - leads.
No. Diodes are made to withstand reverse voltages, that is what makes them a diode. The resistor is to limit the current. They will pass as much current as is available. Often there is more current available then they can withstand and that is why they will burn out.
The exact resistor value is not super critical as it is with a real light bulb. As long as the resistance is high enough to keep the threshold current below what the LED will handle. Too high a resistance will result in a dimmer LED. I’ve noticed the dimming effect beginning at about 1500 ohms when used with a 14.5VDCC output. And there is another key. Obviously a higher voltage will pass more current so all the ohm values being tossed out are assuming a given track voltage. Try a very common 1K resistor and see if that is bright enough for what you need. If not, then do some calculations and move into the lower ohm rating resistors.
My point exactly…that’s what we learned the first week in Solid State Devices class.
You could also find a 5K ohm multiturn potentiometer and use it to help you choose your resistor value, hook it up between your track (or DCC Voltage source) and the light you’re using, then adjust it with a small screwdriver until you get the brightness level you want. Then measure the resistance of the potentiometer with an ohmeter, and pick the resistor closest to that. If you’re not too proficient in electronics, a RadioShack tech will be able to show you how to do that.
This is where I like the MRC sound decoders. They have the headlight output, and three different grounds. One for 12 volt bulbs, one for 1.5 volt bulbs, and one for LEDs. You just hook up your headlight to the proper ground, and the headlite output, and you are good to go. No messing around with resistors. I have half a dozen MRC decoders, and so far no problems.
Dont hold your breath…MRC decoders are well documented here.
David B