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Gordon H

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Everything posted by Gordon H

  1. You must have misheard slightly. The working Brecknell-Willis pans used on High Gill were scratchbuilt in brass (mostly by me). I demonstrated their construction at the first ModelRail exhibition in the early 90's at St Alban's (still got the sweatshirt!), and during the show I lent one to Hurst who were at that time considering the production of a kit. Some time later their kit appeared using brass castings. I did buy one to try out, but found it far easier to continue scratchbuilding instead.
  2. So what? I didn't claim my demo implementation would be directly suitable for the OP - just that you can see something akin to it at the AP show. Nothing to stop the same principle being used with a DC system. Indeed, the same hardware could be adapted to generate a PWM track signal instead of DCC, just needs different code.
  3. Gentle slow down, speed determined by the 'inverse' of the distance measured when within a specified range. The track control is implemented using a second Arduino acting as a DCC command station running 'DCC++'.
  4. If you would like to see an acoustic sensor Arduino shuttle in operation, I should have a demo on the MERG stand at Ally Pally. It uses two HC-SRO4 ultrasonic sensors with an Arduino Uno.
  5. LSC = Linked Section Control RLSC = Reverse Linked Section Control They are both a means of setting up a route, usually without using section switches just the point and signal controls. With LSC the train is driven from the sending end, and with RLSC the train is driven from the receiving end.
  6. Really? How about this whole section of their website: https://www.rapidonline.com/power-resistors How about Rapid 62-8112 or RS 157-550? Suggest you check the facts before making such sweeping statements.
  7. I suspect what you are dealing with here a 5V logic level output from the decoder processor, followed by a diode (and probably a resistor) in series with the output to prevent people accidentally connecting an external power source to it and causing damage. That would explain the off-load voltage that is being measured. I would suggest you ignore the posting immediately above, and try it with a conventional LED and resistor first. If you can, put a DMM in series with it, set to measure milliamps, and see what comes out. Anything in the 2 to 20mA range should be OK, then adjust the resistor value to suit the brightness you need.
  8. The (non-operational) Automatic Crispin was displayed at ExpoEm in 2016. The manual version, in the form of Crispin himself, was also present for the occasion. I have some photographs somewhere...
  9. It will also be at Manchester in December. See picture here: https://www.eventbrite.co.uk/e/the-christmas-model-railway-show-manchester-2019-tickets-71273285315
  10. In similar vein, I think the pantograph base is on backwards. The longer legs should be towards the cab front.
  11. Two potential situations arise from this which would still cause the problem I was alluding to - switch bounce and too brief a pressing. There is no way to guarantee either of these won't occur, and with the level of current involved it only has to happen once or twice to ruin the switch. Far better to use a solid state solution rated for the job.
  12. More to the point, will your push button switches be able to cope with such a large instantaneous current of probably 15A or more?
  13. Can you confirm whether the new signals will work using a on/off switch rather than relying on a momentary switch action like the old ones did?
  14. Did they say whether the switch they now include with it will be an on/off type or a momentary type? Hopefully they have seen the error of their ways and gone for on/off this time round.
  15. It most certainly does have parity checking. The final byte in every packet is an XOR checksum of the preceding Address and Data Bytes - refer to NMRA S9.2.
  16. Surely the drawing board pantograph comparison refers to the fact that on a drawing board it keeps the ruler at the end of the moving arm parallel to the board edge at all times. The railway pantograph does a similar job by keeping its head parallel to its base throughout the allowable range of movement - hence the linkages employed.
  17. To emphasise the point made above, here is another chart which actually uses the term 'Hook-up Wire' for sizes up to 1 AWG. A second chart would be referred to for conversion between AWG and stranded wire nomenclature (e.g. 24AWG is nearly equivalent to 7/0.2)
  18. I did the same before posting my comment, then covered myself by including the word 'usually' on the basis that someone else might come up with an on-going source.
  19. The only advantage of SCART leads is that they are available off the shelf. Otherwise they are pretty hopeless for our use. As has been pointed out their wire cores are typically only suitable for low current audio/video signals (not unreasonable as that is what they are intended for). They have no latching mechanism, so are quite easily dislodged. The panel sockets for them are usually intended for PCB use only, which makes them awkward to terminate with actual wires. I certainly wouldn't use them on a layout.
  20. No, this would not work as suggested. You would need to 'uncommon' one of the signals to allow its individual LEDs to be connected in series with the equivalent second signal LEDs. Easier to wire the two signals in parallel to the single switch and add extra resistors if excessive brightness is an issue. Longevity is not a problem with LEDs if they are treated properly. They are not like filament bulbs in this and several other respects.
  21. It can be, and it does last. See this thread from some years ago: Brecknell Willis Pantographs
  22. The inclusion of connectors will allow far easier fault finding by enabling the isolation of individual baseboards.
  23. Is that indoors or outdoors? Outdoor use of opto detection can be problematic given the wide range of ambient light conditions, and variable direction of sunlight that occurs throughout the day. A self modulated detector with automatic gain control would be needed if a reflective solution is used. This is without considering the potential difficulties of installing equipment under the track in the garden - which of course largely depends on the method of construction. This is why current detection is usually considered a better option in such circumstances.
  24. Doubt whether you would find the springs themselves as spares. Might be worth checking to see if the Peco version of skeleton microswitch is compatible (PL-32).
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