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Topic: Guidance needed (Read 678 times) previous topic - next topic

guyr94399

Hi all,

I have an idea that I would like some guidance on, before I spend any money on and loose any more hair over!!, I'm new to all of this and looking forward to it, but I need to know if it's possible to control 10 rc servos and 1 bipolar stepper motor from 1 Uno board and a lcd/keypad??

I'm looking to control a model rail turntable with the stepper motor and 10 sets of point/turnouts.

Would be most greatful for any help

Guy


Grumpy_Mike

Yes that is possible. You will need an external power supply for the servos.

guyr94399

Mike, many thanks, I understand about the power supply, the current draw would be too high.

Guy

Shpaget

Is the stepper for the turntable? Why not a servo there as well?

guyr94399

Yes the stepper is for the turntable, only because my understanding of servo motor that they only move to and fro.
Guy

Grumpy_Mike

Quote
my understanding of servo motor that they only move to and fro

They can only move through a limited angle, that is correct.

Shpaget

There are servos that have the ability to continuously turn.
There are also variety of servos that have different limits of angles they can rotate to, but all the servos can take any position between the limits their construction allows them to go to. They are not either turned left or right. They can be center as well, or half left or half and 4 more degrees to the left if you wish.
You need the servo to turn no more than 180 degrees, and such can be found.

I'm only asking because adding a stepper requires some other hardware like a limit switch to sense the starting position or a nonvolatile memory to save it, otherwise every time you turn off the system the position of the stepper is forgotten (knowing the position of the stepper is crucial to it's proper function).
Adding an EEPROM is more work and a limit switch approach will cause the turntable to spin a bit every time you power on the layout.

If you already use servos, no reason to not use one for the turntable. It is suitable for this application.

wildbill

Ordinary hobby servos usually have a scope of movement in the 160 to 180 degree range. Look for sail winch servos though and you're looking at 360 degrees or significantly more. If you can find a powerful enough one, it sounds ideal for the turntable.

PeterH


You need the servo to turn no more than 180 degrees


This seems like a valid and important point. If correct, it would simplify your requirements considerably.
I only provide help via the forum - please do not contact me for private consultancy.

guyr94399

Thanks for all your suggestions, I will endevor to try these out over the next few weeks and hopfully come up with something good. :)

rnjorge

Hello,

I model in n scale and I am currently working in the same projects as you are.
I think the stepper motor will be better for the turntable. I may try the mechanics of it this weekend.
Have you found a way to control your turnouts yet?

Best regards
Ricardo N Jorge
Campina SP Brazil

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