A FRED thread

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Greg_Lewis
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Joined: Wed Jan 15, 2003 2:44 pm
Location: Fresno, CA

A FRED thread

Post by Greg_Lewis »

In a thread here: [ viewtopic.php?f=33&t=110825 ] Benjamin was looking for an LED lantern as a rear-end marker. Since he seemed to be looking for something more scale or at least railroad-looking, I thought I’d toss out this thread on a FRED that I made some years back after one of the Train Mountain triennials. Since it goes on the back of a riding car, I didn’t care what it looked like as long as it worked.

One evening at that meet, I found myself down on my knees in the ballast fiddling with my Swiss army knife trying to get the cheap bicycle tail light I had been using to work, while my grandkids waited impatiently for their dusk ride. After about ten minutes of some silent Navy language (kids present, remember), I finally got the thing to light up. But in the next day’s daylight I saw that the innards of these bicycle lamps are below any standard that could be called “cheap.” Perhaps there is a class below that; these would be at least two farther down. The switch and battery contacts are the most flimsy of constructs, and the whole gadget is little more than a waste of raw materials.

So the first project upon returning to my shop was to come up with something reliable. The photos are really all you need. It doesn’t take any brains to put one of these together, which is probably why I was able to make one.

A decent quality toggle switch, a battery snap connector, a few inches of hookup wire, a couple of LEDs and their resistors, and a small project box and you’re on your way. The orange thing is not my idea; I saw these somewhere. It’s a piece of angle iron with three bits of rod welded to it so the whole assembly will fit down over a coupler shank. The only thing that’s not in the photos is the coil extension spring that I put across the two rear legs to keep the gadget from bouncing off the coupler. An unlikely event but just in case.

One thing I discovered is that there are different beam angles for LEDs. While you don’t need one with an extreme wide angle, you don’t want a spot either, so check before you buy. I got the LEDs and the resistors from Chinese Ebay sellers. A package of many from Asia is cheaper than onesies or twosies bought domestically. You can get LEDs pre-wired with the resistor already attached which is perhaps a better idea. One of the photos shows a piece of gasket paper I glued over the wiring to keep it from shorting out against the metal of the 9-volt battery. Hot glue holds the LEDs and the resistors in place.
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Attachments
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Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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Greg_Lewis
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Re: A FRED thread

Post by Greg_Lewis »

A piece of gasket paper insulates the wiring from the metal 9v. battery case.
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Here's the finished FRED on a coupler. The coupler is in a drill press vise in my shop — the riding cars are all stashed in the trailer out in the back field.
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Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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Benjamin Maggi
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Location: Albany, NY

Re: A FRED thread

Post by Benjamin Maggi »

A nice idea. Thanks!
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
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