Flasher for a MTH 7 Light Pennsy Block Signal MTH Part # 30-11013

Forum sponsor, Evan Designs has blinking 3mm bulbs. just add to power source and they blink. 

Here are 3mm flashing LED's in all sorts of colors.

http://lighthouseleds.com/led-...shing-round-top.html

Hello John, thanks for the info on these flashing LED's.

I will keep this in mind i have another brain fart I might want to try and this might be the ticket.

Thanks again !!!!!

Hi John,

If I use a flashing LED in a circuit with a non-flashing LED strip, do I need to be concerned with feedback from the flasher?

You want to power a flashing LED separately, when it flashes the current draw changes.  It could cause all the LED's in the strip to change intensity a bit, depending on the ratio of current draw for the flashing LED vs. the LED strip.

If you're using the LM317 regulator chip in the current-regulator mode as described in your other postings, you can switch over to the LM317 voltage-regulator mode with the addition of 1 resistor.

The hookup instructions for the 20 cent flashing LEDs that GRJ links suggests you need a resistor (value depends on voltage available).

Presumably you've found the desired brightness with the existing LED strip,

1. Measure the voltage at the LED strip.  It will probably be around 10 Volts DC. 

2. Calculate the 2 resistor values needed to set the LM317 to 10 Volts output.

3. Look up the resistor value needed to operate the flashing LED from a 10 Volt supply.

So for about 30 cents, you can add a flashing LED to your LED strip; that's 20 cents for the flashing LED and a couple pennies each for a resistor.

Edit: I found this photo from an earlier thread showing the LM317 hooked up in voltage-regulator mode (vs. current-regulator mode). 

In this case the regulated output voltage was 3V but on-line calculators for the LM317 select resistors for 10V or whatever you need.  There are differences in opinion on this but I suggest if you are mixing 12V LED strips with other "loose" LEDs such as individual marker LEDs, blinking LEDs, etc., you should configure the LM317 in voltage-regulator mode.  The additional cost is a few pennies for the resistor and a couple extra solder joints.