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Scratch Building a Rotating Sign Question

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  • Member since
    July 2006
  • From: Mannheim, Germany
  • 26 posts
Scratch Building a Rotating Sign Question
Posted by coblesan on Sunday, July 8, 2018 6:35 AM
I am very interested in scratch building a rotating sign similar to the Miller Engineering Signs (https://www.microstru.com/Rotating_signs.html).  I have read many posts on the synchronous motors and using the AC terminals on your power pack to operate the rotating sign.  I understand the building design of the sign and how to light it using an LED.  My question is how to make sure I am purchasing the correct synchronous motor (similar to the Faller 180629).  I see many inexpensive synchronous motors sale that are used for turntables in microwaves, etc., and not being an electrical expert, I want to make sure I am not going to blow everything up when I plug in the rotating sign.  Any help/advice you can give is greatly appreciated.
  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Sunday, July 8, 2018 8:23 AM

If I was going to build a rotating sign or any thing that slowly rotates for that mater I would use a micro servo,  There are several YouTube videos on how to modify a SG90 servo for full 360° rotation.  You could use a cheapo servo tester to drive it or an Arduino to do fancy things with it.
 
 
 
 
 
 
Have fun, it sounds like a slick project.  Post a video when you get it working.
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
    July 2006
  • From: Mannheim, Germany
  • 26 posts
Posted by coblesan on Monday, July 9, 2018 9:52 PM

Thank you Mel.  I will do some research on the micro servo.  I am not that great with electronics and wanted to keep it as easy as possible.

 

Thanks again,

Mike

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Monday, July 9, 2018 10:33 PM

If you go with a cheapo servo tester and a SG90 servo it will plug in to the tester without any mods.  All it needs is 5 volts to run the servo.  I did the 360° mod to a SG90 and it requires the servo being dissembled and soldering in a resistor.
 
The SG90 servos are pretty powerful and the speed and rotation (CW/CCW) can be changed by the controls on the tester.   Can’t get any easier to do.
 
If you need any more info or help send me a PM.
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
    August 2013
  • From: Richmond, VA
  • 1,890 posts
Posted by carl425 on Tuesday, July 10, 2018 10:36 AM

Don't over complicate this.  Just get yourself one of the old Switchmaster motors.  These were Hankscraft display motors - purpose built for exactly what you want to do.  Varying the DC voltage will vary the rotational speed.  Hook it up to a cheap DC wallwart.

Here's 6 of them for $30.

https://www.ebay.com/itm/6-Hankscraft-Motors-usable-as-Switch-Machines-like-Tortoise/202332627660?epid=16017937184&hash=item2f1bf6e2cc:g:HcAAAOSwbX1azrjr

I have the right to remain silent.  By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Tuesday, July 10, 2018 11:02 AM

I’d check with the seller before buying the Hankscraft Motors, he states that he has more but only showing one.  Make sure it’s 6 for $30 plus $14.17 shipping.
 
The servos can be had for under $1.50 off eBay (10 SG90s for $15 free S&H) and the servo testers are under $6.
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
    November 2016
  • 476 posts
Posted by j. c. on Tuesday, July 10, 2018 11:18 AM

i built a rotating sign some time back using a motor out of a junked out clock 1 rpm max , the big problem i had was building the wiper as sign had 4 sections to it couldn't find a wiper that was small enough so i had to make one.

  • Member since
    March 2011
  • 156 posts
Posted by owen w in california on Tuesday, July 10, 2018 4:51 PM

I agree with carl. These are simple to hook up, and everything you need comes in the kit with the motor, except a double pull/double throw toggle (DPDT). These are sold new (and I think you can buy singles) from builders-in-scale.com as the SwitchMaster. From them, the motor comes with excellent instructions and a 1200 ohm resistor you solder to one of the leads, which results in a pretty slow rotation of the motor. If you want to slow it down more, just get a resistor with a high number. You might have to experiment on the bench a little to get the rotation speed you want, but it's as easy a model railroading electrical effort as they get.  I use them for turnouts and for an automated brakeman. Joel

  • Member since
    July 2006
  • From: Mannheim, Germany
  • 26 posts
Posted by coblesan on Saturday, July 14, 2018 6:48 AM

Thanks to all who have answered my post.  I am going to do some more research to which way would give me the best results.

Again thanks,

Mike

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