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Found 12 results

  1. Hi to one and all. over the last 5 or 6 months that I have been involved in RMWeb, there have been many productive and interesting discussions about Arduinos and their applications, including stepper motor driven traversers and turntables, and signal / point control. I promised to post some sketches (otherwise known as programs, source code, etc.,) and rather than have it in different threads, I thought I would start a new topic, and add pointers to the threads where relevant. I hope this makes sense, and doesnt cause the Mods a brownout. I firstly bought a Raspberry Pi when they first came out - I have had very little success with this, probably due to a lack of finding the right examples and bits of source code to copy from. Also, Linux is to me, at least, a bit of a black art, and my earlier programming experience was in Algol 68 (yes, I said "earlier"), Fortran and Basic. The Arduino is programmed in C, which is pretty much like Basic, without the line numbers, and many examples are included in the IDE which you can download here ;- http://arduino.cc/en/Main/Software The Arduino website has a full language and syntax reference, plus links to various forums (fora?) in which help seems to be readily available. http://arduino.cc/en/Reference/HomePage I have no connection to any of the traders or sites mentioned. The code I have posted is available to download on an "as is" basis with no warranty of any sort, and is free to use for non-profit - please do credit me (or any other contributors) where applicable. IF you are planning to incorporate it in something you plan to sell, please PM me and we can discuss crossing my palms with gold... first instalment to follow very shortly... best SD
  2. After showing some old stuff it is time to introduce my current project. Donnersbachkogel. Donnersbachkogel is an Austrian layout, located somewhere in the pre-alpine area. The old station building of Donnersbachkogel is also the terminus of a narrow gauge line which was in the past used to get minerals from a remote mine to the mainline. Today the mine is only running as a showmine and instead of minerals mainly tourists are transported up the line. At the station is also the connection to a single track electrified main-line. Not many trains stop there today, main traffic is on weekends to bring tourists to this attraction. We are somewhere in the early 90th of the last century. Besides OBB stock also independent rail companies are starting to be visible in the business and some multi system engines are in use as it is not far to the neighbour countries Italy and Switzerland, which have either a completely different power system (Italy) or a different allowed profile (Switzerland) so that multisystem engines are convinient as one engine can cover it all. The name Donnersbachkogel was chosen as it sounds pretty Austrian but it isn't an existing location. Donnersbach comes from a stream which thunders down a gorge and creates a thunder like noise, kogel means hill, which in Austria can also look like a proper mountain. The idea is to use 4 modules for this layout, about 15' long and with a possibility to loop around at both ends to allow continuous operation. There will be a scenic break so that the return path which goes through some sidings will stay invisible. Track for H0 is Peco finescale code 75, for H0e Peco 009. Small update : DCC from Lenz is used on both lines, controllers are LH100. Changed to Z21 - a much more up to date system. The Lenz went into the box and was not taken out any more since I have the Z21. Decoders in the locomotives are mainly from Zimo. I plan the use of megapoints controllers, it will be probably 4 boards (or even 5 - depending what gadgets I will build in...). ​The control will be done by a homemade mimic board using the mega points multipanel. This should reduce the wiring between layout and mimic board to a great total of 5 wires.... We will see if this works... I started working on the modules in January 2016 - and I am not as far as I wanted to be. Find below the track plan for the layout which has been created with the free software SCARM. I can recommend this software, even I can handle it... It contains libraries for all common European and some overseas track systems, Peco is completely covered and also flextrack can be used. .projekt12 by Gerhard Novak Will be continued.
  3. To continue a discussion on MERG Servos from SI modelling thread, does it make a huge difference? I only ask because this is the third one that I have built, and they seem to work okay as they are.
  4. Not sure this is the best place for this. It applies to the remote operation of points (turnouts) regardless of whether the layout is DC, DCC, clockwork, steam or battery but as there doesn't seem to be another forum for remote point control I'll put it here. There are several point motors on the market that use "stall motors". Basically they use a DC motor to move the tiebar and when the tiebar can move no further the motor stalls. When it stalls it is still exerting a force to keep the tiebar in position. That's bit different from many other types of point motor that only supply intermittent torque and either rely on friction or some sort of over-center spring to keep the point blades in position. Generally it's not a good idea stall a DC motor. It's likely to overheat, but if the power supplied to the motor is limited to an amount that the motor can easily dissipate without overheating there isn't a problem. SG-90 servos are very inexpensive. It's not at all difficult to access their motors directly and it's quite simple to modify them for continuous rotation. Why not use them as stall motors to control points? Based on my (limited) measurements it looks like a stalled SG-90 motor with 0.7 volts across its terminals (and passing a current of 0.17 Amps) will restart when the stall force is removed. In the stalled condition it is only having to dissipate 0.12 watts.
  5. Had a nice chat with the proprietor of this little company today. If you are considering servo operation of points and or signals have a look at http://loolee.org/megapoints/ . There's quite a few useful youtube clips linked from the site too. As a user of servos, I'll be giving it a go for sure! Cheers Jon F.
  6. MOD: Please merge with an existing topic if appropriate. Here is yet another servo point-motor hack. As you can tell from the pix, I'm not kidding when I say "hack"! I would not go as far as calling it as a prototype - it's more a "proof of concept". I have a version that uses 3D printed parts and a much smaller micro-switch rather than the finely crafted plywood and gigantic micro-switch you see here. The "production" version has the micro-switch mounted alongside the servo body rather than at right angles to it, and the actuator bears on the underside of the cam, but it's a lot easier to see what is going on with this version. "But, how does it work?" I hear you ask - or more likely you don't. This is how you connect it. It's very similar to a light that's controlled by two switches. When you flip the panel switch, the motor starts and keeps going until the cam flips the micro-switch. When that happens, as both motor connections are now at the same potential (either 0 volts or plus volts), the motor stops. When you flip the switch the other way, the motor reverses until the micro-switch flips in the other direction at the other end of the cam rotation. The micro-switch does not immediately flip when the cam starts to rotate because its actuator arm is pressing against a segment of the cam that has constant radius and positions the actuator at its mid-point. This works because of the hysteresis produced by the over-center "snap switch" inside the micro-switch. The actuator always has to move beyond the mid-point of its travel before it will snap into the other state. The advantage of this method is that there is no current draw at all when the motor reaches the end points, and it is completely immune to electrical interference. Also, no momentary switches are required, so the panel switch position indicates the point setting. It works best on 1.5 volts. To make it easy to set up, I cut the end stops off the final gear in the servo, but that is not essential. For automation, a relay or electronic buffer could be used instead of the panel switch.
  7. Has anyone installed one of these? http://www.heathcote-electronics.co.uk/uncoupler_oo_gauge.html I'd be interested to understand their experience of it in use.# In a recent discussion on Graham Muspratt's 'Canute Road' thread, he has explained his own solution to the uncoupling problem, based upon Dingham Uncoupler electromagnets, see: http://www.rmweb.co.uk/community/index.php?/topic/114980-canute-road-quay/ I have a dreadful misture of all types of coupling on my layout and I need to standardise, especially for those wagons that I intend to shunt, so I am keen to identify the optimum solution. All help welcomed! Tony
  8. First problem I had with wiring up the MSE servo unit to drive the signal was that of power supply. My Accessory power bus on Summat Colliery is driven by a laptop psu and whacks out 18v DC, great for supplying CDU units but likely to fry the controller box that needs 12v DC. Now, the MERG pulsed accessory decoder boards I use also have an option of an on-board 12v regulated supply to drive small steady state devices. These parts are optional in the build, but thankfully I saw fit to fit them "just in case". 5 minutes probing with a multimeter told me that I had 12v across the small capacitor next to the voltage regulator so two wires were soldered to either end of said cap and threaded through to the controller box The controller box was screwed to the underside of the baseboard and wires were run from it to a switch on the Peco point solenoid (controlled by the MERG decoder) and power applied Dynamis connected up and hey presto, fire the catch point and the servo does it's thing - now to fix the servo and connect it to the signal
  9. I was not sure whether to post this as a topic or a blog. As it's probably going to be a bit "long winded", I thought a blog might be best - so here goes! Like many others I have been messing around with servos to control the points on my OO layout. In the process I've discovered a few things that might be helpful to others who plan to do something similar. There are some advantages associated with using servos, but there are also some challenges that must be addressed to obtain the most reliable operation. Probably the greatest advantage is the cost of the inexpensive servos available. For that reason, all my experience is based on the least expensive servo that seems to be available, the SG90. The Advantages: Low cost Slow/smooth operation (no seismic events) Can produce large amounts of torque (turning force) relative to their size Control by simple single-pole changeover switch Switch position indicates point setting (no additional indicators required) Not difficult to interface with automation and interlock circuits Can be connected in parallel for crossovers, slips etc. One inexpensive driver circuit can drive almost any number of servos (this might take a bit of explaining) Low power consumption (when working properly) The Challenges: Can produce intermittent or even continuous "buzzing" sounds Electrical interference (particularly with long connecting wire runs) can temporarily drive servos "bananas" Can be a bit tricky to make a reliable connection between servo and the point tie-bar While there are not that many "challenges", they can present some serious problems that might discourage modelers from taking advantage of these inexpensive devices. Bear in mind that we are trying to use these devices in a manner that is quite a bit different from their intended application in radio-controlled aircraft, cars, etc. Both the application and the environments are quite different from a typical model railway, so it should not be a surprise that we have to account for these differences. There is not a great deal of information available on the internals of these servos, and it's probably best to try to explain what I've been able to find and figure out for myself. The better we understand the beast, the more likely we will be able to tame it. The next post will go into the internal operation in some detail.
  10. I wonder if anyone can assist with a problem I am having with my Megapoints system? The system has been working well, controlling eight points, with one multipanel processor and a servo controller board. I have yet to instal any signals.I However, often when I switch power on there is no chatter of servos adjusting their positions, just a whistling sound akin to the sounds of modems. The light on the multipanel processor comes on properly but the reassuringheartbeat light on the servo controller does not nor do the servos respond to the switches. However, sometimes it powers up properly and works fine. I am tempted to try a reboot and if that fails swap to a spare servo controller card but I am worried that I have done something wrong and would damage the replacement card. Any thoughts? Ian Ian
  11. Dear all, I tried to reprogrammed my servos (mainly the initial position adjustment) with my ESU switchpilot servo but I could not. The ESU switch pilot servo is powered by an Hornby Select as follows: ESU Hornby SELECT pwr A Track A trk A Track A pwr B Track B trk B Track B I then as directed, powered the system on and hold the a button until this one flashes: it does flash But that's where the prog sequence stops. At that point I should be able to adjust the initial position of the servo 1 but I can not do anything. I rechecked the connections OK I resat the ESU no change. Can anybody help please? Thank you Luc
  12. Some time ago I wrote up my circuit for driving Fulgurex/Lemarco point motors. I haven't given up on these, but needed something more compact for a small space. As a result I've been looking at servos. My initial thought was to use a picaxe microcontroller, something I had played with some time before. However looking at other options I liked the look of the Megapoints controller, which I thought would provide a saving in time and effort. Which they would have done apart from a couple of problems I had. I have to say that these are not problems with the Megapoints board, just with me and to a lesser extent, the setup I wanted to control. Specifically I don't get on with push button programming, and the points I was trying to control were on a run of about 12 feet. To make matters worse the cheap servo extension leads I bought were proving unreliable. So I looked back to picaxe. One of the things I was looking for was a solution which would allow a small cluster of points to be controlled economically. So the 21 servo Picaxe board was out of the running. In the end I settled on the 20m2 chip for its neat layout, with the 4 programming/power pins at the top, 8 inputs one side and 8 outpiuts the other. There is an 08m2 chip which could be used to drive just two outputs, but I don't know if it will be worth writing the slightly different code it needs. I think that the advantages of a single standard 8 servo board means it can occasionally be underused without undue waste. To begin I bought a 20M2 starter kit, which provided me with most of the bits I needed to run some initial tests. I found the programming easy to relearn, and got servos running easily. The next step was to build a stripboard version of the circuit, missing out the programming socket, as all chip programming can be done on the development board. I've made my usual mistake with this prototype in making it too small. I'll make the production ones larger to allow fixing holes and space for feet. I've used resistor arrays to keep the build compact, but there's no reason why separate resistors couldn't be used, though a bigger board might be needed. The dil input connector on the left is just for testing, it only needs to be a single row for practical use. The board uses separate supplies for electronics and servo power. I'll update with a finished circuit board soom, but if anyone wants more info or circuit/program details, please ask. Thanks Dave
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