Z Scale Crossing Signal

[peteski]

I have been into electronics as a hobby and later profession for many years and build numerous 555-based circuits.  If the Gemini solution doesn't work as expected, try the circuit I posted. As I mentioned, some things about that circuit don't look rigth.

[Jesse6669]

I have been into electronics as a hobby and later profession for many years and build numerous 555-based circuits.  If the Gemini solution doesn't work as expected, try the circuit I posted. As I mentioned, some things about that circuit don't look rigth.

Hey @peteski , how do you recommend I strip the non-conductive paint off of super fine (magnet) wire as found on pre-wired 0201 LEDs?  I've been using fine sandpaper but there has to be a better way...

[Lemosteam]

Thought I shared this with you once before.  Not trying to step on @peteski 's toes as he taught me this many moons ago. 

Add a glop of solder to a wide tip iron and just push the end of the wire through the blob. cleaned and tinned in one step.  eventually the blob will clog with enamel, but just wipe it off and add another glob.

[peteski]

OUCH! My toes hurt! 
Yes, I use the same method John does.
There are multiple types of enamels. Some are more heat resistant than others.   But when I dial my iron to 800 deg, F it will pretty much strip any enameled wire.  Before I dip it in the ball of solder on the tip of the iron I fist dip the end of the wire in my favorite electronic non-acidic flux paste.  That seems to make the stripping and tinning easier than just sticking a dry wire into the solder.

[Jesse6669]

Not surprisingly, Gemini's circuit didn't work.

Also not surprisingly, the circuit recommended by @peteski did, but I added an extra capacitor in parallel to slow down the frequency, and increased the resistance on the 0201's since I was using 6v input (2x 3v coin batteries).

Here we go: https://youtube.com/shorts/8EdF5V1jPds

I'm actually pretty excited to have completed this. 

Since I don't want to mess with making a circuit board, what would be a good way to enclose this--or should I just stick it to the framework under the layout?

[Chris333]

You gotta use Claude man.

[MK]

Since I don't want to mess with making a circuit board, what would be a good way to enclose this--or should I just stick it to the framework under the layout?

Put everything into a project box or better yet, 3D print a project box if you can.  It just makes things neater.

[peteski]

Very good!

Yes, the resistor (mostly R1) and C1 determine the flashing cycle time. Adding another cap in parallel or just replacing existing one with a higher capacitance value will slow down the flashing (but so would increasing the resistance of R1).  Of course, like you did, increasing the LED resistor values will make them glow dimmer.  With the high-brightness LEDs the resistor value might have to be seemingly high to dim them down to your liking.

I assume you are running the flasher from 3V?  Just curious: What value did you use for LED resistors?

[Jesse6669]

Very good!

Yes, the resistor (mostly R1) and C1 determine the flashing cycle time. Adding another cap in parallel or just replacing existing one with a higher capacitance value will slow down the flashing (but so would increasing the resistance of R1).  Of course, like you did, increasing the LED resistor values will make them glow dimmer.  With the high-brightness LEDs the resistor value might have to be seemingly high to dim them down to your liking.

I assume you are running the flasher from 3V?  Just curious: What value did you use for LED resistors?

Thanks     I haven't built an electronic "thing" since.. Jr High?  This was pretty satisfying, I must say.

I used a 6V input because the little coin case accepts two 3v batteries and the jumper I put in to make it 3v wasn't making contact well enough, and it's a standard TI 555 chip so not sure if 3v would work. 

The resistors on the 0201 LEDs are 2K ohm.  I used Claude to identify the resistance because I forgot what I ended up with trying to get the brightness where I wanted.. thanks @Chris333 !

I'll probably just put it under the benchwork to power the signal along with the circuit in a project box (must google that now..). 

[peteski]

Sounds like you have it all figured out. 
Just to remind you, the CMOS version of 555 uses less power than the old-school 555. Since you are using small batteries, you might consider replacing the 555 with the CMOS version.  Any thoughts on automating the crossing?