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Junctionmad

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Everything posted by Junctionmad

  1. It’s simple for single leds the forward voltage drop is typically 2.5V for coloured and 3v ( sometimes more ) for white current varies depending on type but these days 5 mA is s good starting point hence using ohms law (supply voltage - led forward voltage ) / current in amps For 12v (12-2.5) /.005 = 2500 ohms or nearest. Adjust the resistor value to get difference brightness.
  2. I read the manual. the system uses magnetic field strengths to record a pattern of magnetic flux for each given location ok it doesn’t then compute position at all. in reality this is just another “ spot detector “ system. It’s the same as RFID except the decoder is mobile and the tags are fixed. disappointing really , nothing new to see here and a whole heap of installation issues I can easily see why he has issues with booster track sections.
  3. Ok so the magnet has a simple coding structure to let the loco know it’s at that point. But how does it deal with multiple parallel tracks.
  4. From discussions I’ve seen elsewhere is is not that you position a series of reference magnets and the system uses a magnetic field sensor to triangulate
  5. Not supporting railmagic but a workable system that can accurately determine geographic position has significant advantages over a known fixed point followed by dead reckoning
  6. That doesn’t seem to make sense. It uses a series of reference magnetic fields to triangulate a position it doesn’t need to know “ how far to travel “ as it can Re compute position
  7. That means you need a computer tracking progress across the route. That means you need a full iTrain style system. no reason if railmagic can resolve in X that it can easily resolve in Y. All you then have to do is run a train over every track route and record a series of positions.
  8. Oh I fully agree. Which is why railmagic now has to produce a full DCc decoder and of sound with no sound either.
  9. I understand railmagic triangulated from a series of magnetic sensors. Hence it should be capable of calculating its current position at snub time and does not need a single reference point.
  10. I also suspect the DCC is being modified to feed back position information rather like Zimo do with their HULU speed protocol , the issues with coupled track boosters would suggest that the issue as the signal is corrupted when fed through two boosters
  11. I should add that precise geographical positioning solves many problems that conventional computer automation can’t easily solve the first problem is that automation software doesn’t know what’s actually happening , it’s “ modelling “ what’s happening , precise position feedback is actually relating what is really happening precise position reporting is superior to point detection mechanisms and modelling profiles . The issue is how the system can generate those precise positions and that the proposed solution works and can be handled by ordinary model railway users and compatible with existing systems.
  12. As I understand it Railmagic works by triangulating positions from known magnets placed in a pattern around the layout. The detector board on the loco has a magnetic field sensor. what not clear is how you are expected to translate that physical position into say a block occupancy signal , surely you would have to map all “ useful “ positions on a layout and record them then access that info and relate it to a track diagram. secondky if it’s used precision magnetic sensing , surely it will be disrupted by motor fields , uncoupling magnets and so forth.
  13. Oh that wasn’t clear from any discussion to date
  14. how can the circuit illustrated actually follow the tie bar, as I understand it when you switch the " direction" switch the LEDs change immediately , even though the button to fire the point motors hasn't actually been pressed ?
  15. Interestingly, the Roco booster manual is entirely quiet on the issue of grounding ** seperate boosters , even though it’s exactly what the issue is. ** by grounding , I mean establishing a common 0V reference on the power supplies to the boosters. All the power supplies to any device feeding the rails needs to have a common 0V to prevent return currents finding incorrect return paths.
  16. My only comment would be that the direction leds will be wrong if the operator ever forgets to push the “ activate “ button , the usual way these circuits are arranged is to use a latching relay driven off the coil pulses , hence the led follows the point motor , not the switches you could also replace the led relay with a simple two transistor set/reset toggle from the pm drive which would do the same thing
  17. We use lots of tam valley juicers on our O gauge club layout. You should see the same voltage measurement as on plain track on the frog ( after a loco has run through the point )
  18. I still have my duettte , I still love the big chunky knob. I actually 3D printed some replica ones for other DC controllers. however the fact is the duette controller itself is very basic , and is easily bested by a simple electronic design from jelly bean components. good for nostalgia value , that’s about it.
  19. What do you mean by ” rattling across “. What’s actually happening
  20. Just in relation to ABC. You can get issues where metal wheels in the stock following the loco bridge the ABC track section and non ABC sections , causing errant behaviour and failure to stop. I’ve had to place very short insulated sections in between the two sections to prevent such issues , but it’s not a complete success , double heading ,carriage light pickups can all cause confusion
  21. Just by way of illustration. My friend has a large OO gauge fixed layout , 18by 12 , multiple levels all code 100 insulfrog it was DC with conventional isolating sections etc. He connected the dcc feed to the track and closed all the section /isolating switches dcc working fine now ( nce ) for several years is it best practice dcc wiring , god no. Does it work , absolutely dcc does not require u to do anything special if U don’t want to.
  22. No you just need the transistor circuit, per point , the capacitors can drive as many points as you need , the leds can be removed if not required hence you have a few jelly bean components per point to derive the advantage of low currents through the switches you do need a 2x transistor for each point
  23. All you ever need to know about CDUs. Near the end there’s a nice circuit that uses transistors to switch the CDU rather then the switches directly ( choice number 9) http://www.talkingelectronics.com/projects/75 Model Railway Projects/75 Model Railway Projects.html#Points PartB quite a nice circuit as it uses standard toggles and provides mimic panel leds as well
  24. Shameless self promotion you could build my dcc dropper boards, Optional dcc indicator led supported £3.50 each plus P&P ( not commercial , just covering costs ) simple to build connectors included etc.
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