Arduino Question

[emmdom]

Hello

First if this is in the wrong section I apologies in advance. I was working up some schematics on how to run my model train when I ran across the arduino post below. I read though all nine pages and was fascinated on what this little board can do and how I believe it can work for me. Unfortunately after reading and watching youtube vids I am unsure as to what I need and if it will cover all my basis.

I want to control with PWM two trains (three if my f units are running) at once along with my turn outs with the arduino. Can I do this with one Arduino Uno R3, and a Adafruit Motor/Stepper/Servo Shield or do I need a L298 Board for the Arduino instead of the adafruit board? I know I will need other electronic components which is fine but as far a microprocessor what is required.

Thanks for all the help:smile:

[Nskale]

I take it you want to PWM DC trains right?

[Papahnash]

Can I do this with one Arduino Uno R3, and a Adafruit Motor/Stepper/Servo Shield or do I need a L298 Board for the Arduino instead of the adafruit board? I know I will need other electronic components which is fine but as far a microprocessor what is required.

If someone on this forum doesn't have an answer, you may try posting on:

http://forum.arduino.cc/

The folks on that forum are very knowledgeable and willing to help.

[pbender]

I have not used the adafruit motor driver shield, but if it is anything like the sparkfun version, it will have H bridges as the motor control outputs.

Paul

[rnjorge]

I've been messing around with the arduino, but I have not come to a PWM setting that I would be happy with. Take a look at these pages:

http://modelrail.otenko.com/arduino/controlling-your-trains-with-an-arduino

http://playground.arduino.cc/Main/TimerPWMCheatsheet and

http://www.instructables.com/id/Wii-Nunchuk-Controlled-Model-Train/

As far as the arduino UNO board is concerned, it will be enought for controlling three trains. I was not happy with the noise the locos make at low speeds, even though I tried all the available PWM frequencies, so I have just given up on Arduino control.

As for turnouts, depending on what you want to do, it will use from 2 to 5 digital ports per turnout.

Using DPDT switches you can use one side to control a servo and the other to change position LEDs, with just 2 ports per turnout. The last code here works fine:

http://forum.arduino.cc/index.php?PHPSESSID=801ceb8810d9823b33a4e7347e6fe6 7e&topic=61780.0

so if you have a lot of turnouts na Arduino Mega will be better.

[CSXRobert]

...
As far as the arduino UNO board is concerned, it will be enought for controlling three trains. I was not happy with the noise the locos make at low speeds, even though I tried all the available PWM frequencies, so I have just given up on Arduino control...

Get two large matching caps, 250 - 1000 uF and 16v or greater. Hook them up ground to ground and hook the + of one to the output going to one rail and the + of the other to the output going to the other rail and it will help greatly with the noise.

[emmdom]

Yes I am looking into controlling dc trains with PWM. I have 10 atlas true track turnouts to control. If this is not possible I dont want to make the investment, I can do what I need to do with switches and block power, but if I can control everything my turnouts and trains without having to invest into dcc then I will look into it. I guess the bigger question is do I have enough IO on the arduino uno r3 to control the 10 turnouts and 3 trains, plus IR sensors to control the trains?

The adafruit shield does have h bridges but what I have found in my searches it that people also use the L298 board and I yet to find a post or post or vid that shows the adafruit in action. Thanks for all the help.

[Nskale]

Yes I am looking into controlling dc trains with PWM. I have 10 atlas true track turnouts to control. If this is not possible I dont want to make the investment, I can do what I need to do with switches and block power, but if I can control everything my turnouts and trains without having to invest into dcc then I will look into it. I guess the bigger question is do I have enough IO on the arduino uno r3 to control the 10 turnouts and 3 trains, plus IR sensors to control the trains?

The adafruit shield does have h bridges but what I have found in my searches it that people also use the L298 board and I yet to find a post or post or vid that shows the adafruit in action. Thanks for all the help.

Well ...

The Uno has 6 alnalog inputs and 13 digital outputs, 6 of which can be PWM. So certainly you can control 3 DC motors (locos) with it (were not dealing with how you get the control signal yet, i.e. throttle method). That leaves you with 6 analog inputs and 10 digital outputs (with 3 PWM).

I use Kato turnouts which use a short DC pulse to switch them. But that comes from the DCC accessory called a DS64. However you could generate a pulse with the Arduino to do it.

But ... you have Atlas switches. I am not familiar with the control method for them. How are they switched? What type of voltage state/transition is required?

So given the I/O available, you tell me - can you use an Uno for your setup? Just think about the number of I/O pins you need vs. what is available as I've listed at the moment. There are some ways to extend the outputs with shift registers but hold that thought ...

[emmdom]

I looked at my turnouts and they are connected to the AC side of my atlas power pack. When I opened the bottom of the turnout they work on a solenoid method. I attached a pic of my layout with some text which I hope helps describe what I would like to use the arduino.
I have 10 turnout switches (SW1-10)which I would like to control with the arduino, along with what I call my 7 blocks. The red lines across the track indicated places where I plan to add isolation rail joiners and spst swithces.
First I have a staging area for 4 train labeled train 1-4. The plan is to have a spst on BLK 4-7 so that I can power only the train I want to run, the spst on BLK 1-3 is so I can have some passing lanes. There are also two DPDT switches on BLK 1 and 2 to reverse the polarity indicated by the blue lines is where I isolate BLK 1 from 2. So with that do I have enough outputs on the arudino? ... I don't know if I understand correctly what you said previously then no I dont have enough IO on the arduino uno R3. I believe I need 17 digital to control the switches and blocked power spst. Not including at least 3 pwd outputs. Please correct me if I am wrong.

THanks

[emmdom]

Forgot to add image.47827

[rnjorge]

Well, for each turnout you would need to use two digital ouputs, one for each coil, and a circuit like the one showed here:
http://www.instructables.com/id/Controlling-solenoids-with-arduino/
That's 20 outputs plus the parts used to drive the coils.

[emmdom]

Thanks Ricardo!
So from what I gather so far 20 digital for turnouts, 3 pwm (digital outs) for loco control seems to me that the arduino mega is a better fit for what I envision. Do you all know if shields that are the same form factor as the arduino r3 work with the arduino mega.

Thanks everyone.

[rnjorge]

My personal opinion: It is not woth it!

I was going the same way. I have a small DC layout and I wanted a control pannel with LEDs showing the turnout position and, as I woulb be usining an Arduino I also wanted the pwm for speed control.

After a lot of investment in time and money I decided to use this for the turnouts (I'll be ordering the 10 bundle this week). http://www3.sympatico.ca/kstapleton3/751D.HTM

For speed, I got two of these http://www.bakatronics.com/shop/item.aspx?itemid=383 and, apart from the humming at low speeds, they are very good.

I only think the arduino would be a good choice if you would use servos.

But, it is only my personal opinion...

As for the shields, I have never tried with the Mega.

Let me know if you are more successfull then I was.

[emmdom]

Well Ricardo after a day of research I think I may stick to the solid state approach and ditch the arduino idea. I plan on building some capacitor discharge units for my turnouts, blocking my power and using the power packs I have for now. I can build that for the same price as the arduino and the shields, plus it seems that I will still have to build additional circuits then program the unit. Very interesting idea but that adds more time which is very limited for this project. There isn't or atleast I have not found a clear cut how to run a train with an arduino there is still a lot of look here look there and that is where I am getting confused on what I actually need and what I can actually do. I wish I would have found someone who has a layout running off and arduino with a list of parts this is how I did it. Something I may want to dive into later for now I am not convinced.

Thanks again for all the help!