Large Scale Radio Control

russmc Jan 9, 2009

  1. russmc

    russmc TrainBoard Member

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    I have begun constructing a radio control system for large scale trains. If anyone is interested, I have a series of posts on an electronics forum at another site you can read and see where I am so far and generally where I'm headed. At this point I plan on making it open source for anyone to build.

    http://www.kronosrobotics.com/forums/viewtopic.php?t=894

    This is something I have wanted to make for a while and finally have some time to pursue. So far the motor control is working very well and if I want to spend a few more dollars I can get current feedback from the motor in real time. The radio is amazingly noise resistant and very inexpensive. It also requires a pretty short antenna. The real test will be in how it performs inside a locomotive. I have used the radios extensively in a product I make and they are reliable to around 100 yards.

    The board I will design will plug into an Aristocraft DCC connector. It will have a daughter card slot for the motor controller, the Pololu one first since it seems to be working quite well.

    I'm not sure if I'll make the system battery or track powered. I would like to make it either/both, battery primarily but if on powered track and the locomotive is idle it would charge the battery. That is in the future.

    I know there are products offered out there that I can buy, perhaps even cheaper than I can make it but I love building things like this, getting in over my head but still figuring it out. I'd appreciate any feedback.
     
  2. russmc

    russmc TrainBoard Member

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    I have the radio working using a simplified protocol. The receiver board is designed and supports speed, direction, lighting, bell, whistle/horn. I may also add two other accessory relays but that will depend on how much room I have. Here is a short video of it operating on my bench, unfortunately it's not on the track yet.

    [​IMG]
     
  3. russmc

    russmc TrainBoard Member

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    Here is the video that everyone has been waiting for, well someone may have been waiting. A short piece of track for testing.

    [​IMG]
     
  4. russmc

    russmc TrainBoard Member

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    I put receiver on a smaller breadboard so it would fit in the locomotive housing. Testing at H&R Trains went very well today. I verified outdoor operation. Worked reliably at about 75 yards away, couldn't go far enough to make it fail. I think it surprised the folks at H&R it worked so far away. Here is a video of it operating today. I should have the receiver PC boards by Thursday. That will make a much cleaner look. Now it's time to work on the transmitter design.

    [​IMG]
     
  5. russmc

    russmc TrainBoard Member

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    I completed a prototype rotary throttle control. The transmitter is also sending signals to control a total of 16 simultaneous locomotives. The controller does not yet have the graphic interface added yet. Fifteen of the locomotives are ghosts right now but it does put the transmitter through its paces.

    Here is a video of the prototype transmitter. The throttle is sensitive to both how far and how fast it is turned. This gives pretty precise control at low speeds and allows the engineer to get the locomotive up to road speeds fairly quickly.

    [​IMG]
     
  6. russmc

    russmc TrainBoard Member

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    The receiver boards are in and now tested. Also, created the first handheld with graphic LCD readout. Not much graphics yet but that's just coding at this point. Here are pictures.

    Receiver board complete:
    [​IMG]

    Receiver board inside Aristocraft SD45:
    [​IMG]

    Transmitter with all major components installed:
    [​IMG]
     
  7. russmc

    russmc TrainBoard Member

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    Made a lot of progress on the transmitter after a redesign. I simplified a lot to reduce power consumption. Now I have a 2 line LCD display, no significant graphics but it works very well.

    I can successfully control 16 locomotives with different addresses simultaneously. It is possible to MU by using the same address and tweaking the motor controls if they are different locomotives.

    Also provide on/off for a Bell (latched), Momentary Horn/Whistle control, and one accessory with momentary control. The receiver stores address and motor control information in eeprom sent by the transmitter.

    I haven't built an enclosure but here is a picture of the wired up transmitter:
    [​IMG]

    The display shows Loco number 3 being controlled. Running in the ">" direction at 100 out of 255. The Bell is on "B". At this time the second line is just for show, Acc 122 will eventually be selected and controlled via keyboard. The accessories will be radio controlled switches, etc. My main concentration is on locomotive control. That required all the timing work in the transmitter. The range doesn't seem diminished but testing should let me know conclusively. Previously the range was about 100 yards. I will know more next week. I have placed receivers at the far corners of my house and they still operate fine.

    New receiver boards with serial eeproms will come Monday so I can finish testing then. I'll rig up a few other locomotives for live testing. Right now I have one locomotive and several protoboarded receivers throughout the house (got to test distance).

    I guess I'll start writing up the magazine article soon so anyone can build it. It's been a fun project. On Monday it will be 20 days from design to completion (if anything is ever complete)

    I plan on adding/figuring out:
    Accessory control for the transmitter
    Computer interface so your PC can have all the fun
    Figuring out how to make the transmitter look sharp in a case of some sort
    Designing the accessory remote units (one unit to run multiple devices, etc)
    Adding multiple cab controls so a second person can play (teathered or radio linked)

    HMMM, it may be a series of magazine articles!

    If anyone has some feedback, now is the time to give it...
     
  8. sandro schaer

    sandro schaer TrainBoard Member

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    that's an interesting device. are you using it from batteries or track powered ?
    how much load can the loco mounted device handle ? 5 amps ?
     
  9. MOPMAN

    MOPMAN TrainBoard Member

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    I am running a switcher set with a powered GP35 and dummy GP7 with rechargable li-poly batteries and R/C board inside in HO. However, my install is much simpler. The big advantage I believe is that no track power is required. So far I have run this setup about 7 hours without a recharge.
     
  10. russmc

    russmc TrainBoard Member

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    The current receiver installs are track powered but I have also run on battery. The receiver motor controller can handle up to 30 amps continuous with a heat sink, 14 amps without. The Aristocraft SD-45 has drawn a bit under 4 amps for me but I have been told it has a motor stall draw of around 9 amps.

    My testing was on the dirtiest run of track I had. It operates amazingly smoothly at low speed on track that regular locomotives wouldn't even run on. I don't know if it is a testament to how well the SD-45 picks up power or to how well the receiver works. On Monday I will install in more locomotives.

    The end plans are to use battery power but when on powered track recharge the batteries. The first order of business was to create the radio control system though, that is nearly complete. I haven't delved into recharging yet. There are a lot more options with G-Scale since there is more room.

    One last note on the transmitter, I had some time to make special characters for the LCD so now there is a pseudo graphic intro screen and I have arrows, a bell and whistle for the run-time display.

    The HO battery setup you describe sounds very interesting. I would like to see pictures of that installation! I have been amazed at how much can be crammed into an HO diesel and even how good the sound is when equipped. Battery power too would take the cake!
     
  11. MOPMAN

    MOPMAN TrainBoard Member

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    I'll try to post a photo with a little more info this weekend.
     
  12. russmc

    russmc TrainBoard Member

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    Here is the transmitter in it's first case. You can see the little train characters as they move from left to right across the screen.

    [​IMG]

    Going to test tomorrow at H&R Trains to see if there are any problems. Seems to work well from anywhere in the house. Monday I will get receiver boards so I can wire up two locomotives instead of just watching one prototype board and one actual locomotive.
     
  13. russmc

    russmc TrainBoard Member

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    The transmitter has all the basic features I wanted now. It also supports 100 non-locomotive accessories. Here is a quick video of its operation. Sorry, no locomotives in the video. Hopefully I can choreograph that soon.

    [​IMG]

    I still need to complete the accessory receiver for turnouts, lighting, etc. Shouldn't be nearly as complex of a receiver. At this time, I assume that all accessories have individual receivers. Shouldn't be too difficult to have one receiver control multiple accessories, just need to figure out how the transmitter will program the accessory receiver.

    Added some labels so I don't get confused. :)

    [​IMG]
     
    Last edited by a moderator: Jan 25, 2009
  14. russmc

    russmc TrainBoard Member

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    Got the final receiver board today. Now it is programmable by the transmitter. Works perfectly. Here is a picture of the receiver with motor controller daughter card plugged in:

    [​IMG]

    20 days from ordering first parts and laying out design to all initial requirements complete.
     
  15. MOPMAN

    MOPMAN TrainBoard Member

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    Here is the pic I mentioned earlier. There are three li-poly batteries wired in series (11.4 volts) and the Kyosho R/C board from an R/C car. The wire running to the lower left of the pic goes to the motor in the GP35.

    [​IMG]

    The gear tower for the rear truck was removed to make room for the batteries. The antenna runs along the top of the locomotive.
     
  16. russmc

    russmc TrainBoard Member

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    That is a very cool install. The batteries look like the ones I use in my electric RC helicopter, very nice.

    My transmitter is a little easier on the eye now:

    [​IMG]
     
  17. russmc

    russmc TrainBoard Member

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    Update:
    The transmitter now controls 32 locomotives. I am now working on a PC interface for both automation and adding multiple cabs. I think I can pretty easily double again to 64 locomotives but I want to concentrate on the PC interface first. I improved the radio protocol efficiency significantly so I'm not really certain what the upper limit is anymore. I will run out of variable space on the microcontroller before I have a problem with the radio protocol.

    The receiver:
    - Direction
    - Speed
    - Directional lighting
    - Bell
    - Horn
    - 4 other accessories individually controllable (brought out on a separate relay card)
    - Stores address from transmitter
    - Stores motor setup information from transmitter
    - Stores default direction from transmitter

    I should have a sound board shortly so I can test its operation in one locomotive.

    The PC interface should open up a lot of options including:
    - Internet control
    - Automation
    - Several cabs
    - Wireless cabs (802.11 networking)
    - Internet browser based cabs running on PDAs, portable PCs or even cell phones
    - Ability to program your own interface
    - Integration with onboard train camera for realistic operation of each cab
     
  18. russmc

    russmc TrainBoard Member

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    Here is a quick video showing control of 3 locomotives.

    [​IMG]
     
  19. russmc

    russmc TrainBoard Member

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    Received a Dallee sound board for the SD-45. It requires 8 wires to connect, 6 to the Aristo DCC plug (2 speaker, 2 motor voltage, 2 power) and two to the receiver (1 bell, 1 horn).

    Here is a picture of the installation in the SD-45:
    [​IMG]

    Here is a quick video where you can hear sound. Camera doesn't record sound well so you may need to turn up the speaker a bit:
    [​IMG]
     

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