Electric/RC/PF points: best way and best PF motor?

[Pierre_Cochereau]

Hello all While I'm not new to the site and do some occasional posting, it's mostly related to discussions regarding soon-to-be-released sets etc. This time, I have a question for you guys who are familiar with MOCs and PF in train layouts, so I'm hoping my post is in the right category. If not, I hope the moderators can push me in the right direction.

I'm wondering about the possibility of adding PF to train accessories such as points etc. to make them work, or rather, I should say I'm wondering about what's the best MOC or concept to do so. I have looked at some approaches and suggestions such as Mark Bellis' solution using the PF Servo Motor or this topic over here. I went through some issues of the Railbricks magazine, and I looked at some YouTube videos of some people presenting their ideas.

In light of the imminent release of the PF Servo Motor, I was wondering if any of you guys had some good ideas or suggestions as to electric points/points motors. As I am planning to deliver my extensive collection of LEGO sets from their current habitat (i.e., plastic boxes sold by a certain Swedish furniture store ), electric points are not only handy but even indispensable when it comes to points located somewhere in the middle of the layout, hence hardly accessible. I realize there might be some issues with controlling the motors (they need their own channel); I am thinking about using one 8869 Control Switch for each points motor instead of an IR Remote Control as the latter option would inevitably result in the simultaneous action of two or more points motors, depending on the total number of motors used in the layout.

Other things I'm curious about would be electric level crossings (triggered by a sensor detecting the approaching train) and working signals (coupled with a "release trigger" allowing the train to move when the signal shows green). However, as these are separate issues (which would also include the use of non-LEGO electronics), some of which may already have been answered, I would post them later and as different topics.

I would be open to use other components (i.e., non-LEGO sensors, relays, etc.), but again, since the PF Servo Motor is said to be released soon, I was wondering what you guys think.

Looking forward to reading your thoughts!

Edited July 6, 2013 by Pierre_Cochereau

[JopieK]

I prefer using Arduino and a 3$ china made servo. It works very, very well...

Here are my building instructions for that kind of servo:

http://www.ministickers.nl/shop/instructions/instructions-arduino-point-controller.html

Here video from a decoupler using the exact same technology:

Hope to upload more next week in my vacation :)

Ps for normal points there is NO modification required! For cross points it also works well, but one needs to modify the points a bit.

[Pierre_Cochereau]

Thanks, JopieK, that's another great option! I like the idea of just using a relatively "cheap" servo motor (compared to PF motors) and just putting it in a custom-built Lego casing. The Arduino you mentioned, I guess, would then be needed to control the motor (to give the impulse), right? I did an online search and found it on Conrad electronics website, so it should be easy to order.

I like that decoupler, too! Again, it comes in handy when needing to decouple some cars in an area of the layout which isn't easily accessible.

[JopieK]

Well, conrad is quite expensive, clones can be bought from dealextreme. Apart from that I have my Dutch stores of course. For LEGOWorld 2013 in Utrecht I want to have a PF remotely operated train layout with Arduino and so that is what I will work on this vacation ;)

The only thing you really need to do is receive the PF signal from your PF remote (using a simple IR receiver, it is some kind of transistor), there are great libraries for that, I can supply them of course :)

I do it the other way around b.t.w. just using an IR LED. So I let the trains be controlled from the Arduino (with another nice Arduino library). I promised to write articles on it in rail bricks, so also need to finish those in the vacation :)

[Duq]

The Servo motors are big and expensive. I'll stick to M-motors for points for now: http://www.eurobricks.com/forum/index.php?showtopic=67730

[JopieK]

indeed, that is why I use very small servo's not from LEGO...

[Pierre_Cochereau]

Duq, thanks for the link to the topic ... I hadn't seen that one yet. I agree that the Servo Motors are quite bulky ... regarding the pricing, I don't know if there is any information on that yet, but presumably they will range above the € 8.99 for the M motor. Also, there might be an issue regarding the stalling of the motor (if it isn't a servo motor), and I haven't found this issue being addressed in the topic discussion: Suppose you use a constant power supply such as a 9V transformator and connect the M motor with a 9V-to-PF connector, together with a switch, then operating the switch would cause the motor to turn, but its rotation would be stalled by the resistance of the points when the end point is reached. I can't imagine that that is conducive to the durability of the motor. That problem could be avoided when using servos – at least I believe so. Hence I would tend towards using servo motors, and I agree with JopieK that using non-Lego components would be a more acceptable solution, both in terms of size and price range.

For LEGOWorld 2013 in Utrecht I want to have a PF remotely operated train layout with Arduino and so that is what I will work on this vacation ;)

That is in connection with the Jaarbeurs, right? I had thought about visiting, but unfortunately, that's when our choir trip to hungary will be ... Still, looking forward to maybe seeing some pictures?

The only thing you really need to do is receive the PF signal from your PF remote (using a simple IR receiver, it is some kind of transistor), there are great libraries for that, I can supply them of course :)

So what you're saying is, you actually need to operate the points using IR? I was thinking of using a constant power supply and then operate the points individually using switches ...

Edited July 7, 2013 by Pierre_Cochereau

[JopieK]

One doesn't need to operate the points using IR, but one can easily choose to! I'm working on a system with the iPhone / iPad using BLE (Blue tooth low energy).

Is indeed in the Jaarbeurs this year (unfortunately for me since I leave near Zwolle).

I also use servo's for signals (arm signals that is) b.t.w. but then I use a very tiny linear version. I have experimented with memory / shape alloy wire but that was not good enough.

[zephyr1934]

If you stay 100% lego you don't even need to wait for the servo motor, the M-motor is powerful enough. You can find the details of my design in the RailBricks 12 REC reveal. I used a 9v train transformer to supply power and PF polarity switches to actually switch the switches, as discussed in this thread. You could probably get smaller and cheaper using non-lego switches. It is great fun to switch cars around.

[kieran]

One doesn't need to operate the points using IR, but one can easily choose to! I'm working on a system with the iPhone / iPad using BLE (Blue tooth low energy).

Is indeed in the Jaarbeurs this year (unfortunately for me since I leave near Zwolle).

I also use servo's for signals (arm signals that is) b.t.w. but then I use a very tiny linear version. I have experimented with memory / shape alloy wire but that was not good enough.

Can I ask which module you are using?

[Pierre_Cochereau]

zephyr1934, thanks for your input. Yes, I've seen the Reverse Engineering Challenge in the Railbricks magazine (as I've mentioned in my first post), but I was unaware that this was in fact you, so I apologize for that. Here are the YouTube videos I mentioned: A solution using an M-motor (the same guy has also other solutions, including modifying the points and using a non-Lego motor in a custom built Lego casing), another

(but way beyond my horizon) which I kind of like because of the smooth servo action in operating the points rather than the click-clack operation, then

using the Technics linear actuator (which I don't like due to the bulky concept/the space needed and the necessary parts not being available individually), as well as

which again uses a motor not from Lego.

Again, my concern would be the stalling of the motor. I realize that the PF polarity switch is set to "off" in the middle position, and after throwing the switch and operating the points in either direction, one would return the switch to the "off" position. Yet there is a brief moment of stalling the motor, and this every time the points are operated. I'm wondering if this would cause damage to the motors in the long run. And this, coupled with the size/prize issue, is why I'm tending towards a solution using a servo motor not from Lego. – Do you have any insights as to the stalling?

Edited July 9, 2013 by Pierre_Cochereau

[zephyr1934]

Oh, no need to apologize, everyone looks the same in cyberspace (grin). Looks like you have been doing some great research. I have 9v switches, so I view a $6 motor as being a lot more replicable than the switches. I have stayed away from solutions that require switch modification strictly as a matter of personal taste. Though I like the snap of the switches, being nostalgic for hand throwing them for so long, but again, that's all a matter of personal taste.

I haven't done thousands of trials with my switches yet (still waiting to do a semi-permanent set up), but so far I haven't had any problems with stalling the motor. I suspect it would greatly reduce battery life if battery powered. All of my pole reversers are "spring loaded" (actually rubber band loaded, but same idea). So unless it is a very young child, the motors only stall for a fraction of a second. I also have an m-motor on the 0-6-0 switcher and that stalls every time I change the on-board uncoupler and sometimes that one will go a few seconds in the stalled position if I have a bad line on the IR. So far it has only wasted power from the battery.

I am looking forward to getting a few servo motors, those would hopefully solve the stalling problem and offer a little more power than the m-motor. My first thought for the servos is the uncoupler.

[JopieK]

Can I ask which module you are using?

What module do you mean?! For BLE you mean? I have two types from RedBearLabs, and a recent one from Dr. Michael Kroll.

[kieran]

What module do you mean?! For BLE you mean? I have two types from RedBearLabs, and a recent one from Dr. Michael Kroll.

Hi,

yes sorry for the BLE, I looked a while ago but the cost was very high so I gave it a miss