F.R.E.D.

Yes, It is a DIP switch. I could not find a switch small enough for this to make it as concealed as I wanted. So, I took a DIP swith and cut it in pieces like a loaf of bread, cleaned it up, and make individual SPST switches from it. Tidious work, but that is what I had to do to get the switch I wanted for this project. The smallest DIP bank you can get is a DPDT (or two gang), and I wanted a SPST, so, inginuity, and determination gets the job done.

 

Now it is all coming back to me, I have used single position SMD dip switches in my previous life.... Just search for it at digikey and select number of positions to 1 and find one that works for you and buy the same at Mouser or other places where it would be cheaper. Sometimes at a surplus shops you can get a strip of 10 for a $.

Digi-Key Part Search

Tudor,
Your idea is very innovative... Do you know how long does this battery last if left ON continuously?
Kim

 

Not sure. It holds 3 batteries. I have a couple of these that I have been beating the heck out of for over a month working with it to get it to act the way I wanted it to, and they are still going strong, (well, the ones I haven't destroyed, lol..) I really want to turn one on and just let it go to see how long continuous use you can get though. But at this point, I have never tested that.

 

I have made FREDs with the following

a clock IC - M9218, LM 3909n
a capacitor - Sprague 8652(6.3 volts)
a switch
a 1.5 volt battery
a 1.5 volt LED

By changing the capacitor you can change the flashng frequency on the LED. I solder the wire right to the battery saves space. With this I can place it in the smallest Z scale car.

I have put them in Marklin passenger observation cars and numerous MTL cars, with no over heating problem. How ever in the MTL car you must isolate them from the metal floor, or it will cause a reaction in the metal.

 

you can use a button cell, I never tried a AAA(too big to fit in a Z car)

 

Substitute for the LM3909

The LM3909 chip has not been in production for many, many, many years. If you are lucky to find some for a $1.00 then jump on them (and let me know where you got them cause I want some toooooo). You can find some on Ebay from time to time for around $10.00 each the last time I checked.

Here is a schematic of what the LM3909 chip looks like when hooked up as a flasher.


Very simple circuit to build, but having the LM3909 chips would be easier. Just add the capacitor and the LED, throw a battery to it and away you go!!!!!

This is what you will have to use in order to reproduce the components to make this flasher with regular electronic parts.


Again, if you know of a cheap source for some of these LM3909 chips, please let me know!

Hobo Tim

 

FRED Circuit

Here is a circuit specifically built to be used as a FRED/EOT in Nodel Railroading.



Hobo Tim

 

Tim the last time I bought them was 2 years ago at radio shack. I will go check to see if I can get sme more from some where(dan stirpe usually has a source for electronics, i will also check with him).

JD

 

Tim I just checked on ebay, and there a source called powerandlight selling them for $5 a piece, 4 available, and littlediode_usa, says he has 191 available, $7.98. I think I paid 2 for $5, back two years ago.

JD

 

I was thinking about alternate to battery and pickups.
Unfortunatly, with plastic wheels, you just forget pickups.

But not only since I have an A4tech battery-free mouse,
I think that it may be possible to load an onboard accu with
inductive leap.
You just put small reload on every pass over this track portion.
Its like a transformer with no iron, primary coil is on the track,
perhaps under a piece of rail, secondary in the waggon with
small loading electronic for cap or accu.

For the Fred, you can just use blinking Led. There are some 3mm
on the market that flash about 1Hz and electronic already integrated.
(Kingbright)

 

http://www.trainboard.com/railimages/showphoto.php/photo/79455/ppuser/7217 I'm not sure if this link will work, but if so this is a schematic of the circuit that I use, only 6 parts using a 555 timer, not including batteries or PCB. No need to find expencive LM3909's.

Michael

 

yes, the link works. thanks for the schematic michael.
dave f.

 

Rob,
it is pF. Ceramic caps are usually in pF. Here is a freq calc.

http://ourworld.compuserve.com/homepages/Bill_Bowden/555.htm
Kim

 

.15uf. Here's the Digakey part #'s I use, they are all SMD's:
IC, LMC555CMMCT-ND
.15UF 50V CERAMIC CAP, PCC1865CT-ND
47.0ohm 1/8 WATT RESISTOR, 311-47.0CCT-ND
47.0Kohm 1/8 WATT RESISTOR, 311-47.0KCCT-ND
10.0M ohm 1/8 WATT RESISTOR, 311-10.0MCCT-ND
RED LED, ANY 2 VOLT

I haven't ordered in a long time so I'm not sure if the part #'s have changed. If you use these parts they can fit on a 8mmx8mm PCB. I've also used .1uf 50v ceramic cap, but don't remember the differance. Hope this helps.

Michael