The OP in his OP asked for...

I want to power a small dc motor (the kind you get in radio control cars) to work in a way such as a windscreen Wiper.

And then it spiraled down in complex "advice" including servo motors..
...Until someone had the great idea of...

There is a mechanical aspect to this that could simplify things.

Only then did a mechanical solution as the OP suggested "like a windscreen wipers", become a good idea - maybe because it was NOT the OP's idea?

A mechanical oscillator like a windshield wiper is a good idea. It would eliminate a lot of things you don't otherwise need.

The easiest way would be to make a mechanical arrangement of the sort used in windshield wipers. That way, the motor doesn’t need to be reversed.

There are several possible arrangements of the arms and eccentric wheel, searching for “how does a windshield wiper work” will get you several ideas.

it's a small wonder why the OP asks for some way to outsource this simple project.

 

If I was to just have the arms moving continously without the stop start and loop. What will I need? Thank you for all your help

OK if we scratch the doing something to music something I would consider is just using a small servo motor. While not exactly a heavy torque motor a hobby type servo motor combined with a simple uC (micro-controller) should work. There are literally hundreds of code samples out there so the coding is just a copy and paste. Looking at the available code samples available one can start to get an idea of what the code is doing and how it is doing it. The link uses an Arduino hobby board but any very basic uC would work including a PICAXE Example. Nice feature is eventually with a few more added parts you may be able to incorporate the music feature. A uC like the linked Arduino could easily drive one or two servo motors. A single servo with the right mechanical linkage could have a stuffed toy move the arms, This forum has several threads about Animatronics Animatronics is a multidisciplinary field integrating puppetry, anatomy and mechatronics.

Anyway unless this plush animal has some very heavy arms a simple inexpensive servo hobby motor may be worth considering. This way you have fewer wires and no need for limit switches. Here is an example of four servo motors with a few attachments for under $10 USD on Amazon. You are on your own for additional linkage and mechanics.

Just something else to consider.

Ron

 

OK if we scratch the doing something to music something I would consider is just using a small servo motor. While not exactly a heavy torque motor a hobby type servo motor combined with a simple uC (micro-controller) should work. There are literally hundreds of code samples out there so the coding is just a copy and paste. Looking at the available code samples available one can start to get an idea of what the code is doing and how it is doing it. The link uses an Arduino hobby board but any very basic uC would work including a PICAXE Example. Nice feature is eventually with a few more added parts you may be able to incorporate the music feature. A uC like the linked Arduino could easily drive one or two servo motors. A single servo with the right mechanical linkage could have a stuffed toy move the arms, This forum has several threads about Animatronics Animatronics is a multidisciplinary field integrating puppetry, anatomy and mechatronics.

Anyway unless this plush animal has some very heavy arms a simple inexpensive servo hobby motor may be worth considering. This way you have fewer wires and no need for limit switches. Here is an example of four servo motors with a few attachments for under $10 USD on Amazon. You are on your own for additional linkage and mechanics.

Just something else to consider.

Ron

I wonder if one of those cheap servo testers can be set for a oscillation in a particular range. I know they have some automatic functions and they are ~$10.

 

I wonder if one of those cheap servo testers can be set for a oscillation in a particular range. I know they have some automatic functions and they are ~$10.

Yes, they are pretty easily set. I got one several years ago and they are pretty cool little motors. Most offer travel of 180 degrees, some a little more and some a little less. The little hobby flavors use a pulse on their input line, typically a VCC, Ground and a Control line. A pulse width of 1.5 mSec is like a neutral, A PW of 1.25 mSec is 0 degrees and 1.75 mSec is 180 degrees. Becomes easy to get the servo to just oscillate or have it do any number of things. Normal frequency is about 50 Hz so as long as the frequency remains the same the servo will stay where we put it depending on the pulse width. So if we simply place a 50 Hz (not really too important about 50 Hz works fine) and vary the pulse with between 1.25 MSec and 1.75 mSec the arm swings 180 degrees or so. Easily driven with even a tiny 8 pin uC. You just loop a few lines of code and they oscillate back and forth over and over again. I wish we could get the erector sets of years ago.

Ron

 

Yes, they are pretty easily set. I got one several years ago and they are pretty cool little motors. Most offer travel of 180 degrees, some a little more and some a little less. The little hobby flavors use a pulse on their input line, typically a VCC, Ground and a Control line. A pulse width of 1.5 mSec is like a neutral, A PW of 1.25 mSec is 0 degrees and 1.75 mSec is 180 degrees. Becomes easy to get the servo to just oscillate or have it do any number of things. Normal frequency is about 50 Hz so as long as the frequency remains the same the servo will stay where we put it depending on the pulse width. So if we simply place a 50 Hz (not really too important about 50 Hz works fine) and vary the pulse with between 1.25 MSec and 1.75 mSec the arm swings 180 degrees or so. Easily driven with even a tiny 8 pin uC. You just loop a few lines of code and they oscillate back and forth over and over again. I wish we could get the erector sets of years ago.

Ron

Yes, but I was referring to the testers that exercise the servos. Little boxes that let you run them manually or with automatic patterns. I know they can do the full range but I wonder if they can be set to do a fixed smaller range. It would be an easy way to get the motion without building anything.

 

Easier to make this plush toy human size and pay someone to get inside,.

 

Yes, but I was referring to the testers that exercise the servos. Little boxes that let you run them manually or with automatic patterns. I know they can do the full range but I wonder if they can be set to do a fixed smaller range. It would be an easy way to get the motion without building anything.

Yes, you can have whatever you want. You just change the control signal. They are also easily driven using a 555 circuit but in my humble opinion a uC is a better way to go. They are popular in Animatronics as well as commercial units for commercial applications. Anyway you can pretty much have them do whatever you want them to do.

Ron

 

Yes, you can have whatever you want. You just change the control signal. They are also easily driven using a 555 circuit but in my humble opinion a uC is a better way to go. They are popular in Animatronics as well as commercial units for commercial applications. Anyway you can pretty much have them do whatever you want them to do.

Ron

Somehow I am not being clear.

Here, this:

https://www.amazon.com/HJ-Consistency-Controler-Helicopter-Airplane/dp/B07GB3HFGZ/

This automatically exercises a servo for testing. It can run them back and forth, or control them manually. I was wondering if there was a version that had adjustable span.

 

Somehow I am not being clear.

Here, this:

https://www.amazon.com/HJ-Consistency-Controler-Helicopter-Airplane/dp/B07GB3HFGZ/

This automatically exercises a servo for testing. It can run them back and forth, or control them manually. I was wondering if there was a version that had adjustable span.

More in the morningas my evening medsare kicking in

Ron

 

OK, your link is just a simple little servo motor test box. It just sends control signals to the servo. or in that case as many as 7 servos. Since it mentions "consistency test" I assume you can make sure all connected servos respond the same.

Again, the thread starter can do this however they wish going back to a windshield wiper motor rotating in a single direction using a small DC geared motor.

Ron.

 

Latest update is that i managed to destroy a toy that has similar functions which i am going to incorporate in my project. The only problem is that it has a push button so in order to activate the cycle you have to push the button and after a few seconds it stops. Is there another way to incorporate another switch where the cycle continue without the need to push the switch again?

 

Latest update is that i managed to destroy a toy that has similar functions which i am going to incorporate in my project. The only problem is that it has a push button so in order to activate the cycle you have to push the button and after a few seconds it stops. Is there another way to incorporate another switch where the cycle continue without the need to push the switch again?

Can you provide some well lit and sharp photos of any parts you have disassembled, including both sides of any circuit boards?

 

It sounds as though it has some kind of time out in order to save on the battery.
It may have some form of micro controller which would make it a little difficult to modify.
Can you make it repeat by pushing the button just before it stops?

 

I will check it and get back to you tomorrow. Ty

 

One last thing if you push the button again before it stops it just stops

 

What about a double push?
Does it complete another cycle?

 

Yes it does it starts all over again

 

So at a bare minimum, a device to offer a double contact closure at a fixed interval may suffice?

 

Yes please - along as the cycle continues

 

Do you have any details of the internal circuit?