G Scle scratch built FREDs

I want to build two FREDs for my caboose, I think I will put one on each end so I never have to worry about front and back, but for the life of me I cannot think of a good simple way to build a FRED out of primarily household stuff and LEDs.. I have almost a dozen used gift cards that could be used for plastic, and can paint it afterwards but the super glue I have doesn't seem to stick to it (ZAP C/A and Testors' model glue). I thought about drilling a hole in a piece of 1/2 x 1/2 basswood and press fitting a piece of coat-hanger wire into the hole so I could chuck that in my Dremel and making a make-shift lathe, but I doubt I could make 2 the same... or get it centered well enough. . .

I took apart a blinking lolipop/candy ring from a 25 cent machine and found a very compact circuit that blinks an LED off two tiny button cells. I also have a circuit out of a display stand that when the button was pressed would light a colour change LED for about 15 seconds. I have combined the two so that now there is 2 "AAA"s to power it, and pressing the button causes two red LEDs to flash for 15 seconds. I am going to add either an optical sensor or a magnetic sensor and either a slotted disk or a magnet to one axel so that when the caboose rolls, the LEDs will flash for 15 seconds. As long as the axle rotates more than 4 times per minute, the FRED will continue to flash.

Let me know what you all think.

Mike from DieCastoms

P.S. I seem to be the only person posting in the G scale forum... Am I posting too much or should I not worry about it?

 

Here's a thought.

The local electronics store has 'blinking' LEDs in a variety of colours. The circuit, or what acts like a circuit, is built into both the 3mm and 5mm product. They should activate at 1.5 Volts and if you install a current limiting resister, say 1K, it will protect the LED at a constant brightness right up to your top track, or battery, output.

That way you can simply install the LED in an appropriate shaped box and hang it over the coupler. Some very small 2 pin connectors are also available should you decide to uncouple it from your source from time to time.

I'm sure no engineer but they've worked for years as turn signals and hazard lights in my die cast cars and I've seen these work in HO scale so......

Dave at Winter Valley Regional Railroad - Welcome!

 

Thanks Boxcab. I was worried about overstaying my welcome.

Dave,
I already have the LEDs (purchased bulk from Hong Kong far cheaper than the local suppliers) and am using a circuit that I got from a kid's blinking lollipop of all places. The price was right, 25 cents and turn the handle! I want to use a separate circuit instead of blinking LEDs because then I can make as many LEDs blink at exactly the same rate as I want. Turn signals on a car fir instance blink at the same rate at both ends, etc.


My question was, what do I make the box out of? Would someone like to donate a pair of resin casts maybe?

Off topic, my neighbor gave me a pile of oak that used to be cabinets and will rip it to 1.2 by 1.2 for me to build my first trestle with, and also said he would rip some cedar down, so I may have some trestles for sale soon. If you are interested, whether or not you are ready to buy anything please let me know!

 

I do like your idea about using the labels, I hadn't thought of that and do have some....somewhere...

I had planned on using a switch at first, but with this little 15 second timer I have, I figured it would save on battery by not running ALL THE TIME and not having to worry about turning it off.

Also, it quite suddenly dawned on me yesterday that all I need for the 'sensor' is wipers on the axle and a thin strip of aluminum tape, or a metal axle half painted.. I did some testing with the circuit.. if you hold the button down it still runs 15 seconds and turns off and then no longer draws power, so if the caboose should happen to stop with the wipers on the strip the light will still shut off until the connection is first broken and then reconnected...

Mike from DieCastoms

 

I see what you mean. It's sometimes better to be able to control the flash rate.

Not exactly 'on topic' but.....

http://1stclass.mylargescale.com/dawinter/IMGP0178.AVI

Dave

 

Thanks for posting that link Dave, that is a very impressive scene. You said that's in HO? Have you considered writing a tutorial on how you did that?

I looked up pictures of FREDs. They are incredibly plain, I had not realized it. I had also not realized that they didn't really exist before the 60's. I can make them out of an appropriately painted piece of basswood.

Also, just to throw a little trivia at you, did you know that modern FREDs are more commonly known as End Of Train devices and have a counterpart called the Head Of Train device (which as affectionately known as WILMA since the FREDs are married to them?). Modern EOTs have 2 way radio communication with the computer in the cab and are capable of relaying brake pressure measurements, GPS location, and are capable of applying the brakes from the back of the train, all remotely? Some units even have their own turbine generators powered by tapping air pressure off the brake lines! And I thought they were just a flashing light!


Probably all common knowledge but by now you all know I am long winded...

Mike from DieCastoms

 

I couldn't get a picture of the original HO scene at Northern Alberta Railway - Dunvegan to Dawson before it was distroyed in a fire but the builder, John Green, did that one for me in G scale.

Dave at Winter Valley Regional Railroad - Welcome!