NinOz

I would love to understand what the aim of all this is.   Has anyone used servos successfully as point motors on say Peco 00 code 100 electrofrog?  Because I would expect the over centre spring to cause them grief and without the spring points opening under trains would be an issue.

 

More basic how do you select a route, do you have to select every point direction individually?  Or how do you avoid powering up a stalled servo when the point is already thrown?   Not an issue with solenoids but probably needs a polyswitch or pair of limit stop micro switches per servo.

 

 

Can you make it as user friendly as a Capacitor discharge /diode matrix /solenoid set up (see pic) where just two prods sets up most routes?

 

 

How exactly does one interface with the electronics to operate the points?   

1.  The aim of OP was to describe a concept of using a Raspberry Pi to interface to a servo controller board to allow control of up to 16 servos acting as point motors. Just one of the many options to switch points.

2.  I don't remember which specific points have been used with servos but given the number in use I assume the quoted point has likely been used.  I doubt the type of point will make much difference.

3.  Most people just rip the centreing spring out and rely on the servo gear train holding the point blades in place, takes a bit of force to move even an inactive servo output.  Works OK.  One can leave the spring in and just use a servo which has sufficient force to overcome resistance (my preferred option in N).

4.  Routes would be taken care of in the micro processor via programming.  Can be quite sophisticated.

5.  Stalled servos are not a problem.  Movement limits can be set and stored for each servo, actuating rod is usually spring steel so has a bit of give, servos are generally put to sleep at the end of movement.

6.  Routes can be set up as you describe, the prods (or buttons) just tell micro which route is required, micro then tells servo controller which servos to move, the direction to move each servo and the sequence and timing of servo moves.

7.  Interfacing is dependent on the installation and use.  The simplest is just a small circuit to drive the servo (a dpdt relay, a 555 timer, two trim pots, few resistors and capacitors).  Cheaper is to use a cheap small micro to drive a servo directly.  Both of these could act and be setup rather like the solenoid setup as described.  Can get fancy and go for a micro driving a couple of servos or, as in this thread, driving a servo controller board.

My DIY has a micro(s) in the control panel which detects which route, lights or points are to be set, broadcasts such requests on Loconet, micros scattered about the layout monitor Loconet and react to their specific switch requests and switch their points or any other action required.

great and thanks

that servo control board is the same thing at a fraction of the price

only difference being it confects to a RPi with a few wires

 

as for the arduino pro-mini

I dont think I can give a good comment as I have never used one

 

Does the arduino have WiFi?

I think some people might be ok putting files on an SD card where as they might be put off by having to send the code to the hardware

perhaps its easy I have never done it

 

the problem still remains it needs a bit of code

the code is probably already on the internet

 

If any one can find it or write it please let us all know

The code to control the board from any arduino is fairly simple, IDE and library is available as well as examples (sort of C++).

Mine is a little more complicated as it is DCC controlled and chats on Loconet.  At runtime stores individual servo addresses, closed and thrown settings, last known location, etc.

Programming the arduino is simple, single cable from usb port to arduino (can buy arduino with suitable cable).  The only difficulty is remembering to ensure the correct USB port is selected in the IDE config.

How about some pogo pins instead of the PB strips.

Example:

https://www.aliexpress.com/item/10pcs-Spring-loaded-pogo-pin-connector-3-Pin-Pitch-2-54mm-Surface-Mount-PCB-SMT-brass/32722259285.html

CFJ

Can buy an arduino pro-mini and the 16 servo controller board for about 3 quid delivered.  One arduino can control "N" servo controllers via I2C.

Works ok.  If you are into DCC then the arduino can be used as a decoder.

Examples:

https://www.aliexpre...iceBeautifyAB=0

https://www.aliexpre...iceBeautifyAB=0

CFJ

The DC pulses from the GM are in fact the result of the 100hz wave being produced by the rectifier, these are presented to the motor at a variable voltage, that increases as speed is increased.

This used to be called "pulse injection" to differentiate from PWM.

"the southern black C class sells out before the other versions"

Do manufacturers make equal numbers of each variant (beyond minimum livery run requirements) or adjust numbers of each to their best guess as to possible sales?

CFJ

https://static.rcgroups.net/forums/attachments/6/9/4/0/6/a10475151-176-324932.jpg

I expect the answer (if there is one) will be more complicated than the question, which is

I would like to have 2 input wires and 1 output wire.

One input wire comes from the frog and the second comes from one side of the track. If they are the same, then the output wire will also be live, if not then there is no power to the output.

I would try connecting the track and frog wires to inputs of an AC optocoupler (or two normal ones). If the same potential on the inputs then no output from the optocoupler if different potential then there will be an output.  The output from the optocoupler could drive a relay, power transistor or provide a digital signal.

Would require at least a volt or two DC to get it operating but if you have locos moving about will be no problem.

From memory the H11AA1 (or equivalent) would be suitable.

Regards,

CFJ

Try connecting a 5600 ohm resistor between the servo signal wire and GND. If that does not work then post your program code - preferably a very short program that just demonstrates the problem.

 

...R

Some feedback.

Problem was two faulty servos.  Replaced with new ones and all ok.  Must have grabbed the two from my used RC bits and pieces box.

Just make sure that the current-limit on the stepper driver board is adjusted to suit the motor.

They have one?

Will have to check mine and set.

Thanks.

CFJ

The only problem with £2.50 servos is that they tend to chatter when under power at rest.  I've been toying with the idea of shutting off power to servos using a relay after they've done the job and switching them back on when next required (under Arduino control, naturally).

Anyone know how to stop servos from jumping about when they are awakened from sleep mode?

CFJ

Geoff,

When you release the motor it is no longer "locked" in place.

If it is moved accidentally and your code relies on the last known position then won't work too well.

For my controller, it releases after several minutes of inactivity but seeks a home position on reactivation.

CFJ

Again, it's all down to experience and having the correct tools.

 

Given the above, there is absolutely no problem with lead free solder.

Well I wouldn't say no problem for me.

Lead free has a different "feel" to it in the way it melts and flows which made my attempts to try it a bit unsatisfactory; particularly with fine decoder wires.

But as you say "experience".  I am sure with a bit of perseverance I could get the feel and wonder why I was having so much concern.

I think many people just quit in frustration in the early stages of adapting (like me).  Especially if one already has several spools of the lead/tin alloy to hand.

CFJ

Setup:

Digitrax DCS100, JMRI.

Behaviour:

Can read CVs ok in service mode.

Can write CVs ok in operations mode.

Can write CVs ok in service mode but reports no response from loco. (no other decoder has the same behaviour)

Works fine running loco.

Anyone experienced similar behaviour?

CFJ

Rather than resorting to emery paper, would giving them a scrub with the peco wheel cleaning brush be enough to remove the shine without abrading the metal as much?

 

Good call.

At least there wouldn't be any concerns of any sand paper grit or glass fibres getting into the mechanism, which would be nagging in the back of my mind.

CFJ

Now we just need someone to preach about the "collection of dirt in scratches" myth or hardboard (masonite) is not abrasive.

Just a thought: I had a problem with a couple of old Poole steamers where the draw bar was lifting the rear loco drivers a tad.  Possible on the Castle?  There was also the problem with their tenders fitted with pickups where the wheels wouldn't rotate easily because of the ill fitting tender pickups and the loco just dragged the tender around.

It gives me no pleasure to do this but here is a video of various locos pulling eight coaches up my 1 in 39 grade. If you have a flat layout then the castle is fine but if you have gradients you may need to think carefully before buying. The castle is last up on the film but was third to try the bank during the actual test.

Thanks for that.  I have one incline on my layout so hmmm.

Do you know how many of those coaches it will pull up that gradient?  I assume it can haul itself up ok.

Regards, CFJ

I have started work on constructing arduino based modules for control of my DCC layout mainly with loconet input.  I started out to make another LOCOIO board but thought making a board for everything was a bit of an over-kill so decided to split the board into small dedicated units with circuit and much of the code in common.

In this case I am using ultra cheap pro minis, a Loconet and DCC interface, a simple plug-on programming board (button and 10 position BCD encoder so I don't have to build them on each module).  Modules are built on PCB prototyping boards.  Sketches based on published DCC libraries.

The aim is to simply grab a module and up-load the appropriate sketch to give required functionality.

So far I have a reasonable module circuit layout and have working sketches for;

- a button board to throw switches, each button (8 available) is assigned a single switch address.  Buttons can be toggle or momentary.  Addresses can be programmed.

- an input sketch to report to loconet up to 8 inputs. 

Almost finished a sketch to take loconet switch requests and control slow motion switch motors (Tortoise); input from the track type module is being created.  Still need also to adopt a standard design for powering the tortoises.  Each module can control 8 switches as well as 8 routes of up to 8 switch addresses in each route, programmed via switch requests.

Next in to-do queue is a LED sketch to take loconet traffic and control LEDs on a panel and then a small servo control sketch.

Nothing really innovative, just using bits of other peoples' concepts and work, cobbled together.

All good fun though.

CFJ

 

 Is the interrupt that the DCC is using causing the serial monitor not to work?

Most likely.  Both will be trying to use interrupts to monitor inputs so quite possible that your serial info is being lost.  I doubt that the DCC library was written with consideration of any other concurrent coms usage.

Serial inputs seem to be quite problematic for arduinos, lots of correspondence on the net but little resolutions.

One solution to a similar problem I remember is a chap used two arduinos connected by I2C, one to handle the serial input, buffer and pass to the other.

If you only wanted to send a TON and TOFF to the DCC decoder then could use a second arduino (cheap pro mini type) for serial input  and use 3 input/output pins on each arduino.  Should only take a few lines of code on each sketch.

What does the original BlueTooth (BT) code look like?  Does your BT need specific baud such as 115200 and not 9600?

Couple of unrelated questions:

1.  Does this code return "8": (sizeof(gAddresses)/sizeof(gAddresses[0])),  seems like it should equate to ( 8 * IntBytes / IntBytes )

2.  What does this code do (beside resetting addr to 0 after 8 cycles):

if( ++addr >= (int)(sizeof(gAddresses)/sizeof(gAddresses[0])) )
{
addr = 0;
}

  Can't find any other reference to addr.

Hi all

Can anybody assist me please, I've had a change of layout design and now only have 2 roads to and from the TT. I'd like if possible for it to turn anti-clockwise each time, from the 6 'o' clock position (the head being at 12) so the head rotates back round to the 7 and then slightly on again to the 6 'o' clock when instructed to.

Do I leave out the first set of instructions in the sketch regarding myStepper2 'forward' and the first set in the 'position' instructions ( the 'moveTo' )

Like Lucian, mine also sits and makes a high pitched noise when at rest

Any help would be greatly appreciated.

Thank you

Is this movement still a concern?

For general info, some learning references:

Online:

http://www.learncpp.com/
http://www.uow.edu.au/~nabg/ABC/ABC.html

Free e-books for arduino stuff:

https://it-ebooks.info/tag/arduino/

Some examples from the site:
1. Beginning C for Arduino, 2nd Edition
http://it-ebooks.info/book/5816/

2. Arduino Cookbook

http://it-ebooks.info/book/538/

3. Getting Started with Arduino, 2nd Edition 

http://it-ebooks.info/book/1338/
 

Apologies if posted before or old news.

Regards,

CFJ

Sorry to muck you about a bit but I checked the MynaBay libs and they have been fixed since my original download a while back. 

"prog_char" references have been changed to "char PROGMEM"

So just download and install the current DCC_Decoder library and all should be good with newer IDEs (my 1.6.5 compiles ok).

From here:

https://github.com/MynaBay/DCC_Decoder

Stew,

I can send you a copy of patched DCC_Decoder files to remove the compile error if you are interested.

Hi, just a quick question. Is the Adafruit Digital I/O 2 pin enabled?, as I could not see it mentioned in the sketch in Post #17, only the I/O 3 pin.

 

 

Barry

Not used in the non-DCC test sketch in post 17 as it is the DCC RX pin.

It is defined in post 48 during setup() via the decoder setup call;

      DCC.SetupDecoder( 0x00, 0x00, kDCC_INTERRUPT );

kDCC_INTERRUPT is defined as pin 2 in the DCC library.