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Back in Sept I started a thread asking for some help with a DipTrace project I was working on, linked here. It was a simple flip-flop multivibrator circuit intended to flash road crossing crossbuck leds. During development one idea suggested was adding a 2 gang pot to be able to vary the flashing speed.

The idea was dropped because no one knew of a source for small stacked trim pots. (You need a separate pot for each side of the circuit)

I just got a thing from ebay, one of those “items picked especially for you” deals. It turned out to be a 4 light road crossing signal with an actuator board, made by Eve. Price about 12 bucks. Check out the board:

Evoloution-Eve Flasher Jan 2020

Notice the nice adjustable trim pot, presumably two stacked. The rest of the circuit is exactly the same; 2 x 33uf caps, 2 x 200 ohm resistors, 2 x 50K resistors, and two npn transistors. Wonder where they got the pot idea?

 Coincidence, or are more people reading the OGR forum than we know? 

Rod

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  • Evoloution-Eve Flasher Jan 2020
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Leo; I only just found the above board listing, have not ordered one to try out. But the price seems reasonable for a board and a 4 light crossing head, all for $12. Hard to beat.

While developing the original fixed-speed circuit back in Sept, I also did a variation using a small top adjust single gang trim pot to vary the flashing speed. Then I did a 555 timer version that also has variable flash speed. I ordered boards for each and they both work well. Didn't publish them here because it didn't seem  like there was a whole lot of interest in being able to vary the speed. But if there is I can add them to the shared build files thread that rtr12 has running.

Rod

Last edited by Rod Stewart

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