want to make my own flasher circuit to replace 154C

Hi I would check with gunrunner John on this forum he sells all kinds of different electronic circuits for many different controls and dcs etc! hope this all helps you out there easy to build circuits!

https://www.youtube.com/watch?v=VMXOj8cgv98

https://www.build-electronic-c...ts.com/jk-flip-flop/

https://www.aliexpress.us/item...;utm_term=electronic circuit learning kit&msclkid=5ce3957241bf1e0ce1e9f2aa0e92415d&gatewayAdapt=glo2usa

check this out !

Alan

@Alan Mancus posted:

Hi I would check with gunrunner John on this forum he sells all kinds of different electronic circuits for many different controls and dcs etc! hope this all helps you out there easy to build circuits!

https://www.youtube.com/watch?v=VMXOj8cgv98

https://www.build-electronic-c...ts.com/jk-flip-flop/

https://www.aliexpress.us/item...;utm_term=electronic circuit learning kit&msclkid=5ce3957241bf1e0ce1e9f2aa0e92415d&gatewayAdapt=glo2usa

check this out !

Alan

Thanks - lots of good info.  @gunrunnerjohn sells a product through Henning's, but I'm trying to do a home brew.  And although John deserves a fair return on his idea and labor, the circuit costs almost double what the typical 154 signal costs, and I'm a cheapskate.

In case anyone else is interested, the video you linked is the overview.  It took a little more digging than it should have, but the details for that circuit are here:  https://www.youtube.com/watch?v=2UcorAC1MCU

Interestingly, when I viewed your post it only had the Youtube link, but when I quoted it, a couple of additional links appeared.  (I think you edited it while I was replying)

@JohnGaltLine posted:

The "Go to" device for crossing flashers for quite some time has been the LM555 timer.  This is a simple 8 pin integrated circuit chip, and is cheap and fairly easy to use.  The output of this timer chip can then be connected to transistors or relays to deliver the needed current to drive lightbulbs.  

Here is a basic circuit using LED lights:

You're looking at less than a dollar in parts here if you buy through online suppliers.

@ADCX Rob posted:

In that diagram, am I correct to assume that the purpose of the resistors next to each LED is to limit the current to the voltage they require?  If so, can the circuit power incandescent bulbs if those resistors are removed?

Rod Stewart posted 2 crossing flasher circuits including diagram, parts lists, and Gerber files so you can order your own boards here.

I have built the first version and it works well. Cost is below $2/circuit with components ordered from China (eBay vendors).

Bob

@Mallard4468 posted:

In that diagram, am I correct to assume that the purpose of the resistors next to each LED is to limit the current to the voltage they require?  If so, can the circuit power incandescent bulbs if those resistors are removed?

Good guess, but the short answer is not really.

In this circuit, the resistors form a voltage divider between the power source + and - that allows the 555 output to toggle between high and low voltage states, without directly shorting it to either source pole.  The LM555 can not directly drive a source that draws more than 200mA, like most incandescent bulbs.  The 555's output is intended to trigger solid state device inputs (diodes or transistors) or possibly a small relay coil.

I had an idea that may combine a couple of ideas. Given that you specifically want to operate or build out several of these crossings and have them activated by simple insulated rail. First build a single high current flasher, rather than individual low current flashers at each crossing. Then run a flashing bus- 2 wires that alternate power around the layout just for these crossings. Last, the trigger or return at each local crossing is the insulated rail. In other words, this flash bus power source and the outside rail common of the layout would share common. Then as the train goes around and the wheels connect the insulated rail to common- the flashers flash because the 2 flasher source bus lines are alternating.

Just like any other circuit- a relay could be used to take a low current control signal and close or open high current contacts, but the constant timed click, click, click, might drive you nuts. You either want transistors or maybe even a pair of Solid State Relays (SSR).

Again, in my mind, one could build a simple flasher source from a 555 timer, but key is then making it a high current output to alternate 2 bus lines that all the flashers connect to.

Pros:

1 flasher circuit for the entire layout

bulbs or LED can be used regardless

Cons-

the need for the bus wiring (still less work in theory than multiple flashers IMO).

The design to build a single high current flasher- and not use relays to avoid the click driving you nuts.

FWIW, The CIRCUITRON FL-3 is a complete solid state flasher with three independent outputs that can be used to alternately flash sets of incandescent lamps or LEDs at three separate locations. Three control terminals are provided for use with CIRCUITRON Detection circuits, and this allows individual control of each of the locations. Alternately, the three control terminals may be connected together for increased current capability to provide a heavy duty flasher with a maximum capacity of 750 ma. on each side. The FL-3 contains on-board regulation to allow the unit to be powered by 10-18 volts AC or DC. Best performance will be achieved, however, when a DC power supply is used. The FL-3 measures 3? x 3?.  

Another option, this DC based motorcycle light flasher module. Yes, this would require using a DC power source and would have to be DC common to layout common, but a massive 10A capacity

Skip that- found this one a perfect wig wag 10A capable. Yes, DC, but we can make that work. $25 There is even a customer who made a video of it running an actual bulb based crossing flasher.