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  1. ikallio1

    Modelling aviation obstruction lights in your layout

    I just finished a piece of electronics to simulate an aviation obstruction light on top of my new water tower. It is based on the ATtiny13A microcontroller and supports up to 5 pulsing LED lights you can put on the top of your towers & other tall structures in your layout to make aviation more...
  2. ikallio1

    Scratchbuilding a turntable

    I did think about it, but a stepper motor can lose steps and is therefore not really reliable enough to provide accurate alignment to the approach tracks by itself. I would need to provide some other alignment/indexing mechanism anyway. And driving steppers requires a dual H-bridge. Also (and...
  3. ikallio1

    Scratchbuilding a turntable

    Thank you :-) Life & other interests get in the way of model railroading - hence the lengthy timeframe. Even model RR hobby itself can cause delays in projects - so many interesting things have happened in the meanwhile. For instance, I have been reading up on DCC++ while my 3d printer was...
  4. ikallio1

    Scratchbuilding a turntable

    John, I like that continuous turn potentiometer for rough positioning...I assume you can then assign numbers to each of the approach tracks and command the table to go to a specific one? I have been wondering how I could accomplish that without resorting to complicated optical encoder systems...
  5. ikallio1

    Scratchbuilding a turntable

    I think employing 3d printing for this purpose is a great idea! However, the Geneva drive is fairly limiting in the sense that you have to divide the circle into a certain number of stops, say every N degrees. It would stop at every N degree spot, so in operation it would not look very...
  6. ikallio1

    Scratchbuilding a turntable

    Hehe, I would never drink decaf! But now I have a tapered plate girder beam! I had to massively exaggerate the size of the rivets in order for them to come through at all in the slicer (I'm using Cura) in preparation for the 3d printing process. We'll see how well it actually comes out - it is...
  7. ikallio1

    Scratchbuilding a turntable

    The good thing about having a long hiatus in a project is that technology can catch up to what you need :) That is indeed what has happened in the 6 years this project lay waiting for a better day: 3D printing came out! I have designed the turntable bridge in OpenScad and printed out my first...
  8. ikallio1

    Scratchbuilding a turntable

    ; part 2 ; ************************** ; Main ; ************************** Main: Loop: ldi r16,POTPIN ; // read the user input (CW/CCW) potentiometer rcall analogRead ; PotValue = analogRead(PotPin); mov PotValue,r16 IF1...
  9. ikallio1

    Scratchbuilding a turntable

    In case someone is looking for the Assembly (ASM) code for the ATtiny13A, here it is. It is 428 bytes in length so using a bit more than 40 percent of the available code space. The ASM was hand assembled from the original C code. The original C code is left as comments at the end of each ASM...
  10. ikallio1

    Z scale layout in a Suitcase

    Omg! I have some Marklin Z-scale trains & track and having tried modeling buildings myself in that scale I have to take my hat off for you. Beautiful work! -ik
  11. ikallio1

    Scratchbuilding a turntable

    Oooo, code 70, that looks so nice! Are those approach tracks 8 or 9 degrees apart? That's one area where I have had a nagging doubt - my current design uses 6 degree spacing as in the prototype. I had a feeling the approach tracks would get a bit too close together given the diameter of the...
  12. ikallio1

    Scratchbuilding a turntable

    Finally had some time to tinker with the ATtiny13A. I was going to build a board with the ATtiny13A processor, Voltage regulator and motor driver / H-bridge chip. However I noticed that I can get ready made motor controller boards from Ebay for less than what I would have to pay for the...
  13. ikallio1

    Scratchbuilding a turntable

    Quick update - I started to dust off the project and realized I had "misappropriated" the Arduino for another project as well :-/ Oh well, that processor board was overkill for this project anyway. I have been tinkering with Atmel's lower end processors, the ATtiny series, in particular the...
  14. ikallio1

    Scratchbuilding a turntable

    boy I'm glad I started this build log, sure will make it easier to resume the project some day! The project is not dead by any means. I lost the H-bridge chip to another project, but that can be replaced easily enough. I hope to be able to get back to the project soon. -ik
  15. ikallio1

    Scratchbuilding a turntable

    Sorry for the long hiatus guys, been busy with other hobbies and family life, in general. I hope to be able to blow the dust off the project and post some more progress soon. -ik
  16. ikallio1

    Brown Sand?

    I second Crandell's suggestion about the garden soil. I have used water fractioning to extract really fine material. You need 2 large buckets for this method. Put a spadeful of soil in on bucket, then add water. Let the bucket overflow to get rid of light floating bits - keep vigorously...
  17. ikallio1

    Please give comments on this proposed layout

    Hi Craig, You have a nice big room for the layout! I am also a newbie but I can tell you that your plan is really large for a starter layout. If you're like me you're going to find out soon that your initial plan might not be what you want in the long run. It is a good idea to start building...
  18. ikallio1

    Scratchbuilding a turntable

    Scratchbuilding a turntable: Correcting vane positions Disclaimer This is a construction journal, not a plan to be followed! If you are inspired to build something after reading these articles, do so at your own risk. Take the necessary precautions for safety. Working with powertools and...
  19. ikallio1

    Scratchbuilding a turntable

    Thanks for the information. I went out and photographed some actual bridges locally which I guess are from about the same era as the turntable I'm modelling. It seems the bridges are using some square profile cross ties (maybe 8" x 8") and some rectangular profile ones (maybe 8 x 12). I will...
  20. ikallio1

    Weekly Photo Fun 13 - 19 May

    EFRX 109 undergoing field surgery Since we're posting prototype photos: Local short line needed to swap out the rear motor from their switcher. Had a heavy crane to lift the engine up (see photo 1), drove the rear truck from under the engine using a "portable power pack" (i.e. a...




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