Motorized Rotating Display Stand

[biofilmer86]

I was thinking of getting one of these on Amazon for making circular obliques and darkfield stops using paint pens. These can also be used for slide ringing. Any thoughts on this?

https://www.amazon.com/JAYEGT-Motorized ... r=8-8&th=1

[MichaelG.]

Just one thought … my reading of the Amazon listing is that it turns at 1-2 revolutions per minute !

If I am correct, that is very slow for the purposes you have in mind.

MichaelG.

[biofilmer86]

My current setup is an old computer fan connected to a potentiometer. When I have it running slow, the pen slows it down further to a complete stop. When I have it running faster, the paint no longer stays in nice circles. What I'm looking for is something with constant torque and preferably electric so I don't have to keep spinning it by hand.

[bkt]

Go for a powerful slow runner, any motor + gearbox + robot wheel like that one: https://fr.aliexpress.com/item/32851946942.html

Choose the motor + gearbox for your max speed. Plus maybe little 5V motor that could run from a USB port or 1-2A wall adapter. If the desc is accurate, the above one could probably run from any USB port: "Arduino DC3V-6V DC, 70mA (250mA, MAX) (3V)"...

For acceptable/constant torque, instead of a potentiometer, use any cheap PWM motor speed controller. Something like this: https://fr.aliexpress.com/i/32840532022.html

The build will be easy, the gearbox itself lowering speed and adding torque:

[bkt]

These can also be used for slide ringing. Any thoughts on this?

When I have it running slow, the pen slows it down further to a complete stop. When I have it running faster, the paint no longer stays in nice circles. What I'm looking for is something with constant torque and preferably electric so I don't have to keep spinning it by hand.

I checked what a ringing table could be...

As explained earlier, a cheap motor + gear box (to lower speed and to increase torque) + PWM controller (for speed) should be Ok for this application. A quick and easy DIY project.

The basic PWM setup wouldn't really control the speed, but the power to the motor. It would be more costly and complex to control constant RPM, which seems overkill to me for such an application.

If the motor + gear box is powerful enough, it won't be slowed down a lot by a pen or a brush.

[PeteM]

A classic ringing table will typically have a good bearing, a platen (table) heavy enough to have some inertia, a secure way of centering and holding the slide, and some sort of built-in bridge to steady the pen (brush, etc.). Having a motor to turn it seems the last of the requirements, since almost none of them had one.

I'd make sure those three requirements are in place before trying to motorize it - maybe around 20-40 rpm?? With a heavy enough table, just the old motorless method and a spin with a finger should work fine as well.

Elsewhere on this site there is a thread about a Chinese-made circle cutter than can cut stops up to 50mm in diameter. It has a good bearing, is pretty well made, and does a nice job of cutting black Delrin etc, if you want to cut and assemble stops.

[bkt]

Having a motor to turn it seems the last of the requirements, since almost none of them had one.

They were invented in the 18th century

have some inertia...

maybe around 20-40 rpm??

Here I found some slow runners refs, at 6v and 26, 34 or 50 RPM. Inertia with a table and the high motor /gearbox torque could be Ok. Could do the job with a PWM controller, to tune the 50 RPM model between 20 to 40 under 5V:

https://fr.aliexpress.com/i/4000552517016.html

just the old motorless method and a spin with a finger should work fine as well

Such a gearbox solution will be noisy compared to the historic finger solution

[bkt]

The cheap gear boxed motor + a cheap PWM controller will do the job. RPM won't be that precise, but it shall do the job.

Using an Arduino + a stepper driver + a stepper motor could be another way to get both constant speed + high torque. Overkill, but should be less noisy than a geared motor.

He found an alternate path, a recent stepper motor driver + a NE555 of the 70th:



He had designed a PCB, which is complex...

For a stepper, it will be much more easy using an Arduino: https://how2electronics.com/control-ste ... r-arduino/



Basically, 3 options:
- an adequate gear boxed motor + a PWM controller
- a stepper driver plus a NE555 (frequency/pulse generator)
- an Arduino plus a stepper driver (once build, can be tweaked by software)

[biofilmer86]

I just remembered my dad has more than one record player and it fits my needs. All I have to do is make a small platform to cover the spindle.

[bkt]

I just remembered my dad has more than one record player and it fits my needs. All I have to do is make a small platform to cover the spindle.

Tweaking our micro waves oven plates to run with open door is not an option

Some synchronous motors could run at low RPM. But usually, they run on mains. Using them would be a bad idea.

A geared boxed motor would run at 5V, steppers between 5 to 12V. Which is safe.

[biofilmer86]

You don't know what a record player is, BKT? The model I'm looking at is a Modular Component Systems MCS 6601. It has a direct drive DC brushless motor and has set speeds of 33.33 rpm and 45 rpm.

[bkt]

@biofilmer86 I now watched this. Makes me think it would need a on/off button, your dad and its turntables won't appreciate.

[bkt]

You don't know what a record player is, BKT?

LOL when were you and your dad born? I once was very familiar with my gran'pa 78 RPM

rpm.JPG (36.92 KiB) Viewed 1153 times

[bkt]

Makes me think he runs at on/off/200rpm...

[bkt]

I'd make sure those three requirements are in place before trying to motorize it

Last or main argument being the cost. Using any of dad's turntable being a no go?

I've seen an offer for 42 pounds (excluding VAT).

DIY using a motor + gear box + PWM controller could cost some 5 to 10€.

DIY using an Arduino + stepper + controller + on/off button could cost a bit more, between 20 to max 30€?

The more basic DIY based on a dead 3.5" disc (for its ball bearing), spined/stopped by a finger, would cost nothing but some work. This being an example of what could be build with such a part: https://gadgetbuilder.com/Balplanman/Sl ... inger.html

[MichaelG.]

I would recommend watching Part_1 of that YouTube series by ‘Gordon’ to get a good appreciation of the whys and wherefores

MichaelG.

[bkt]

In the middle, he says he saw nice DIY builds from VCR heads (like hard drives, they have great ball bearings):



Part 1 + 2 being very interesting for all he explains about ringing tables.

biofilmer86 having maybe a specific need: "making circular obliques and darkfield stops using paint pens". Pens/pencils sure apply more pressure/break force compared to paint brushes. Motor + gearbox (long runner at up to high torque, and cheap) could be better suited for this.