Recent content by John P

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  1. John P

    My Custom Point Motor using Servo

    I agree that a linear motion is best for turnouts. I came up with this scheme which I planned to get 3D printed, but ultimately I thought another design was better. This one was prettier though! This was the one I actually did have made:
  2. John P

    How about some OO, and no, not the UK stuff

    What, no outside 3rd rail? I'm disappointed!
  3. John P

    NX control on Android

    I've been using my time in jail lately to program a model railroad app! What the program does is implememt “NX” operation, a concept actually used in railroad control centers. It means “Entrance-Exit”, and what it does is allow an operator to set up a route through a complex area of track by...
  4. John P

    Turntable alignment copied from prototype

    If you can handle electronics and microprocessors, here's how I did it:
  5. John P

    Does HO Track Ever Wear Out???

    I recall at a club near where I live one of the track crew was complaining that people were careless about how much load they tried to pull up a winding hidden grade. People would let the locos slip their wheels, and over the years there had been significant rail wear. The maintenance guy wasn't...
  6. John P

    Scratchbuilding a turntable

    Another point about steppers is that you have to have a known "zero" point to start from. Then to maintain the accuracy all the way out to the bridge, you have to use a geared or timing-belt drive, not a friction wheel like ikallio1 and I both used. That's much easier to set up, but wouldn't be...
  7. John P

    Scratchbuilding a turntable

    I'm in a club where we've built two turntables over the years (first one was in 1980), but we treated it as heavy engineering, with the bridge, bearings and frame designed to be very precise. It's interesting that in the design by ikallio1, the bridge rides on the pit rail, and gets its rotation...
  8. John P

    Can you run enough LED's in series to not need a resistor?

    I was ready to say that current-control component could easily overheat, but then I realized it's not likely. Drop a full 12V across it and at 20mA, you're still only losing .25W, so it would be warm, but not melting. Another idea would be an LM317 voltage regulator used as a current regulator...
  9. John P

    Baltimore Wharf Area, Municipal Piers, Docksider Locos

    Picture taken at the Springfield MA show in 2008. Sorry, I didn't record any details of whose layout this was.
  10. John P

    Can you run enough LED's in series to not need a resistor?

    I won't get into an argument here, but this just isn't good design. You really do need a resistor or some kind of current-control circuit to operate LEDs. It may be possible to make them work without that, but it won't give consistent results.
  11. John P

    Can you run enough LED's in series to not need a resistor?

    Now wait a minute, guys, that's not how LEDs work. Any diode has a non-linear relationship between voltage and current. The way it works is that there's almost no current up to a certain threshold of voltage, and then the current becomes almost unlimited. If you put a bunch of LEDs in series...
  12. John P

    A building, a layout, finally!!

    Dumb joke about two totally different uses of the word "siding".
  13. John P

    A building, a layout, finally!!

    If the industrial sidings go down flat, how come the garage siding goes on the wall?
  14. John P

    Pacific Electric Sunday

    I'm not seeing any pictures in this thread.
  15. John P

    Android game: Train and Railyard Simulator

    I have a long airline flight coming up, and I decided to look for a railroad-related game that I could put on my little Android tablet to provide some amusement. With some searching, I found one called "Train and Railyard Simulator", by 3dinteger, based in Latvia of all places. (By the way, I...




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