# Ok I want to try something with flashing LEDs



## Grabbem88

Id figured this was the best place for this question.

I searched a bit but couldn't find what I was looking for so here it goes.
I have a few engines with dummy beacons and wanted to put a flasher up in there...do you have to have resistors tied in? This is DC ONLY! If so would a 1/4 watt be plenty?

Also I wanted to this also.... I have a few cross bucks with a big enough opening that my red/white LEDs fit perfect in there so I was thinking of getting some reds and slip them in there and maybe run a toggle bridged to my accessories side or straight in but how can I make the flashers be offset? Would a higher/lower resistors create the signal flash I'm going for?

Again thanks for your time and sorry if I put these questions 
In the wrong area...


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## gunrunnerjohn

Yep, a 1/4w resistor is plenty. If you want to run at full brightness, figure about 50 ohms per volt of supply voltage minus 1.5 volts for the LED drop. For example, 12 volts would be 10.5 * 50 or around 525 ohms. A 560 ohm resistor is just dandy here.


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## T-Man

I have articles on flashers just click the bottom of my post and go to the technical area. In Lionel we have AC so we need a DC change over but DC you reverse the rails so It acts like an AC sort of and you still need to convert. If you have DCC the voltages are different. I did post a flasher in an Amtrak perhaps you should see that too.It is under HO links.


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## Grabbem88

Ok cool i thought I was close.
I have a bunch from my rc car projects

So what about flashers for RR crossings how would I delay the flash just so it looks accurate enough?


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## T-Man

Are you using a flashing LED or a circuit?


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## Grabbem88

Flashing led although I seen they make timers but it looks like they require a circuit board of some sort...along with resistors capacitors ect 

I also seen there is a sight they sells all kinds of rtr kits...


I'm not looking for all that stuff I'm a k.i.s.s type of guy but I'm willing to listen if there is a certain required step to follow


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## T-Man

I find more control with a circuit and have not used the single flasher. I am not sure you can change the frequency. I have no way to test it out. SO John is your man.

Nothing wrong with the k.i.s.s. priciple. I would think if you ask a question you would want to see it develope.


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## Grabbem88

http://www.quickar.com/fk109cf.pdf



This is what I was talking about. Is there an easier/cheaper way?


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## T-Man

It is only cheep if you need one kit. I buy parts in group of 20 or more. That way I can do a bunch of different things. It would be cheeper than getting them at Radio Shack. How much is it I like the directions.

I believe this is the circuit.
Well not exactly this one is closer at http://www.bowdenshobbycircuits.info/page12.htm#flipflop.gif

The two transistor LED flasher halfway down the page.


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## Grabbem88

9.95!

You think that's a good deal I'll buy a few try one out put a video up and I'll send ya a kit


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## T-Man

This one is 2.95

I used the model number on a search. Radio shack would carry more LEDs to make it four. Those directions show how to add them.

With a minimum order of 5 and ten for shipping it's 5 bucks each.hwell:

ANother company sumo electronic has them for 7.55 each that includes shiping with no shipping discount for multiple items.


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## Grabbem88

Wow! Ok have you used it? I'm buying in bulk


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## T-Man

No, I am low on resistors but I am into a transistor study, slow that it is. I thought you would like the price. You need to power it and how will you activate it??

My attempt.


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## Grabbem88

Well I thought about a toggle switch of some sort.

I'm gonna try something just don't know yet


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## gunrunnerjohn

For simple flashing, I like the flashing LED's. If you want to control the speed, that board that T-Man pointed out seems to be the bargain deal.


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## T-Man

The directions help that would be a fun little project.

Here it is again

With the transistors I would use a metal clip to heatsink it when soldering.
My last board had problems working.


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## Grabbem88

This reminds me when I used to take old cameras and convert them into shockers! LoL! 

I would like to see something already done and hooked into a crossroad signal 

And just to be sure the capacitor is what changes the flash frequency? Correct?


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## T-Man

With the kit is is the pot, potentiometer that can adjust the rate. This is specifically for a crossing why would you want to change it? The capacitor will change it too. If you dabble in that use a breadboard to decide what you want.

I am not sure how that pot is wired in either. I may have to get the kit to find out.


If you go back to post 9 I added another circuit that has an explanation on rate. The kit is a close adaptaion of it.


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## Grabbem88

I had to use a pot for my camaro lol darn security gave me fits so I had to fix the key chip to work the computer. Kept turning it while holding key till car started.. Lol hope there isn't a car thief reading this but you can start any gm car from 92-97 this way lol

Well I might go to radio shack in a bit 

Could you give me a shopping list on what I need to get?


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## T-Man

That was my initial point a three buck kit is cheep. Radio Shack will be more. BUying on ebay you get 300% more or greater for the money. Initial cost could over 30 bucks because you have zilch. All the decisions are on your end if you wait for me it will take time.

Some costs, 470 ohm resistors are 1.29, a board is 3 to 5. A solder board needs wires too unlike a predesigned board in the package. a breadboard is 5 to 7. two caps start at 1.29. Led package is 3.99. Transistors vary the 2n3904 should work but I got mine on ebay RS may not have them.In fact you may have to shop around because the inventory may vary from store to store. 

At this point I have no idea how to add the pot but I can set up the flasher again for now.


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## JohnAP

The $2.95 kit looks like the exact same board as the $9.95 board. A supply of red leds and poof....there it is!


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## Grabbem88

Well I bought a bunch of stuff all in bulk...I can do 20 flashers if I want
I bought a circuit board instead of a bread board so hopefully that's ok too

I two styles of switches too.


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## Grabbem88

I paid basically 4.00 a set so I'm ok with that


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## Grabbem88

Ok lol what goes to what got a diagram?


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## gunrunnerjohn

Grabbem88 said:


> Ok lol what goes to what got a diagram?


In what context? What are you building, and what are you using?


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## Grabbem88

Flasher for my crossroads sorry

I had it working on the board but something wasn't right to me

I have a pack of caps a pack of transistors and resistors plus blinking LEDs

I bought all kinds of things plus I have stuff stashed from other projects


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## Grabbem88

So I guess I messed up...didnt know blinking LEDs are "fixed" so I need to get standard LEDs?


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## gunrunnerjohn

If you want to vary the blink rate, you can't use the self-blinking LED's. For a variable rate, I'd consider that little board T-Man mentioned for $2.95, probably can't get the components for much less.


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## Grabbem88

Why? I got all the stuff minus the right LEDs apparently lol this is neat stuff I just forgot alot over the years


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## JohnAP

The $2.95 board ships from Canada. Killer shipping rates unless a few got together for a group order.


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## Grabbem88

True! Well I went to a different radio shack and low and behold they had a kit there like the one I posted earlier. Hooked it up and works awesome! Although this one uses two pots but easy to duplicate.


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## JohnAP

I guess you'd have to use surface mount leds for N scale.....another project to ponder!


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## Grabbem88

I don't know I thought the 5mm LEDs was it until I grabbed one and saw it was too big but 3mm fit perfect I guess I got a not to scale crossing lol


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## T-Man

Here is the example.


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## Grabbem88

Thank you so much... Now I'm gonna teach my boy this on the breadboards and have him learn something early.

Btw I got all the wiring done and fabricated onto my crossbucks boy does it look nice!

Now to fun part... Install time!!


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## Grabbem88

Well she is hooked up and looks really nice I'm using a toggle switch to operate lights and I had a left over Traxxas receiver box to hold battery as well 

Post pics later


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## Grabbem88

Got a question.... I think my 9v battery isn't enough and wanted to know if it is ok to power it through a transformer? And I take it that it has to be dc only correct?

I'm trying to power 8 3mm LEDs and wanted to know if only for a beif moment this is too much demand?


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## Grabbem88

http://youtu.be/72zkiTqcIng

This is what it looks like of what I had done.


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## gunrunnerjohn

No problem with a transformer (DC output obviously) as long as the voltage is right. I'd probably put larger capacitors in the circuit to slow down the blinking, but it looks great. 

You're not even close to the ratings of the transistors, so I wouldn't worry about the number of LED's.


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## Grabbem88

I got two pots controlling the lights flash speed I'll get the part number so you know what I'm doing the kit was from Belgium


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## T-Man

Just use a wallwart, a 9 or 12 volt dc will do. Cut the end off and deterimine the positive wire. The easiest way I know.The wallwarts have .1 to .5 amps, plenty for your project.


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## Grabbem88

I think I had dead 9v cause I put a new one in and it ran for a minute and no heat and it's brighter!

Ok the kit I found at radio shack is velleman-kit very easy to assemble small board 

Part number I think is mk102 

The extra LEDs was from some left over valentines heart kit with 28 3mm red LEDs two caps 4 resisters plus heart board which I tossed and it was 6 bucks

Ok so do think after watching video that I have flashers turned up too fast?


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## gunrunnerjohn

Do you have a circuit diagram for your driver board?


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## Grabbem88

Yes nothing for turning it on or off


It killed another battery with switch off so I got a drain in the switch I'm using rs switches or something


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## Grabbem88

I guess I should have used a 4 prong switch instead of a generic 2 prong huh 

Joining two sets of wires must have grounded battery out or shorted it but when flipped on was corrected and was able to power signals? 


Whoopps!


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## NIMT

Why are your crossing gate backwards?  Wrong sides of the road?  Are you an aussie?


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## NIMT

Two prong or SPST Switch is fine you only need to connect on wire from the battery to the switch and the other from the battery connects directly to the board, off of the other prong of switch to the board.


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## Grabbem88

It was a bad switch. And the reason my crossroads are that away is because it's a one lane road hense the construction...


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## Grabbem88

I did my first ic555 unit... I played with the caps a bit and got about as I could get it without my eyes going cockeyed it's a strobe,but no beacon that's probably beyond my patience 

Thanks T-man your info is very helpful

Now how do I transfer this masterpiece to a different board small enough to fit in a train lol


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## gunrunnerjohn

I use perf-board and solder the connections with #32 wire-wrap wire, here's an example. Obviously, yours can be quite a bit smaller with less components.


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## T-Man

I did see the kit at Radio shack . 2 bucks more per unit,but no 15 dollar minimum. I was curious how one operated with just one pot. Now I can'y remember if it had one or two but the first one did have one.


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## Grabbem88

Mine had two and that valentines heart is where I robbed all the 3mm reds it was cheaper to get that instead of buying in pairs

You know what I didn't take a pic of that did I?
Well after the train show Ill take a pic you'd probably could duplicate it for pennies
And it's on a 1.75x1.75 card which is pretty small

With a single pot I'd think it would be better cause I think the adjustments were over rated in terms of usage


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## T-Man

In the drawers at Radio SHack you get a package of various leds,5 and 3mm red, yellow, green, and one weird maybe infrared. Thaishine on ebay has a good deal on 50.


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## Grabbem88

Ok you might laugh at me but I bought a Hershey engine at the train show for 5 bucks and... It has a small circuit board for the lights and such since everything is basically pos/neg could I affix the same resistors and stuff and get the same result?


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## T-Man

You may add LED, Led blinkers, but not an IC, you need 5-12 volts constant for the 555 ic.


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## Grabbem88

Ok didn't know that but that makes sense


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