# Special Project with led and motors

#### Ennolmac

Nov 10, 2016
6
Hello All,

So I've started a project for my wife for christmas. I've made a rose from sheet metal and steel all thread. i plan on mounting it into a hollowed out wooden base. my question is: I ordered a free rpm of 100 reduction gear motor and some LEDs. I wan't to wire it to were I plug it into a basic 12v or 24V dc plug, (I have both) the LEDs stay on and I can connect the motor so the rose will spin slowly, kinda like a lighter display case. Any schematics or videos would be greatly appreciated, or any other parts I may need.

thank you

#### hevans1944

##### Hop - AC8NS
Jun 21, 2012
4,780
Nice rose. How do you plan to mount the LEDs? I hope they will be external to the rose and the motor and you are not planning to rotate the LEDs with the rose. What is a "free rpm of 100 reduction gear motor"? Does the output shaft from the reduction gear rotate at 100 revolutions per minute? That's pretty fast. Compare to this video playing an a 78 RPM vinyl record. You need a rotation speed on the order of ONE RPM or less for an effective display, and a somewhat focused, very bright, LED illumination source reflecting off the petals. Can you provide links to the motor and LEDs you have ordered?

#### Ennolmac

Nov 10, 2016
6
I plan on drilling holes in the base and putting the leds so they shine upwards towards the rose, a mix of red and white led to make it look "magical" as for the motor i ordered a "pololu 298:1 micro metal gearmotor". I'm assuming its no load rpm is 100 judging by the specs (free rpm 100). so assuming some load will reduce that, plus I'm open to a potentiometers, I have a few i just don't know how i should connect all this together to make it do what I want it to.

#### Audioguru

Sep 24, 2016
3,650
The motor spins much too fast. The LEDs do not have any spec's about their brightness and their viewing angle.

#### (*steve*)

##### ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,506
You might be able to slow the motor by driving it with a PWM controller, but I'm not sure you could slow it enough.

Another option would be a further reduction with another gearbox, or perhaps a geared down stepper motor.

#### hevans1944

##### Hop - AC8NS
Jun 21, 2012
4,780
It will rotate too fast. You may be able to excite it with a PWM (pulse-wideth modulated) power supply at a low duty-cycle to slow it down without losing too much torque or overheating the motor, but it really isn't the best choice for your project. You could also slow it down by using a large pulley on the rotating base (a lazy susan base would be ideal) and a small pulley on the motor shaft. You can use a large "O"-ring to connect the two pulleys. However, a synchronous gear-motor operating from the AC mains is typically what you would use, perhaps this one.

Even better would be a commercial synchronous gear-motor that are typically used in clocks and time-operated switches, but these tend to be pricey unless you find one on eBay. Below is an example image, and you can find more here.

The LEDs you have chosen do not appear to be adequate for the job. The specification for maximum current (20 mA) is quite low, suitable for direct-view instrument panel indicators rather than illumination. Also, a white LED is not included in the mix, only your basic red, green, and yellow. Below is an image of a suggested type for your application. More images here.

When your LEDs arrive, experiment with them to see if multiple LEDs will give you the desired lighting effect. Ten or twenty LEDs arranged over a circular area will approximate a Lambertian light source, and that may be good enough. We have a resource here on Electronics Point that will help you connect a string of LEDs to an appropriate power supply. You should read it.

#### Alec_t

Jul 7, 2015
3,285
The turntable motor from a microwave cooker would give about the right rotational speed, and have sufficient torque.

#### Minder

Apr 24, 2015
3,335
The motor you specify is 6v and they show a range of 3v to 9v, you intend 12v or 24v supply, you would have been better off with a 12v or 24v motor and run it on a lower voltage, with that gear ratio it should be able to turn that predicted load at a lower voltage.
As mentioned, a PWM controller could probably do it also.
.M.

#### Ennolmac

Nov 10, 2016
6
ok so some things came in today.

the pwm i ordered:
https://www.amazon.com/gp/product/B00RYRXFW2/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1

a possible motor choice:
https://www.amazon.com/gp/product/B0080DNUC4/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

connected to a power supply;
input: 120vac 60 Hz
output:12vdc 500mA

so far motor is working the way I want. but i also ordered the following;

finished product power outlet:
https://www.amazon.com/gp/product/B01IBFNP7K/ref=oh_aui_detailpage_o02_s02?ie=UTF8&psc=1

and these LEDs in both white and red, I plan on using at least 3 or each connected straight to input power along with input of the pwm:
https://www.amazon.com/gp/product/B007O1WXHG/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

will this work for actually wiring it up or am I going to catch something on fire? sorry I'm kind of new to this i appreciate all the help.

#### Minder

Apr 24, 2015
3,335
Wow, that PWM control shows as CAN$65.00! Roughly same thing on ebay is around$5.00.
Maybe does not have the fancy knob and the switch, which can easily be added.
They are all mostly 555 based and can even be put together one's self for ~ \$5 also.
M.

#### Ennolmac

Nov 10, 2016
6
So I finished the project, I ended up going with a small motor wit gear box hooked to a pwm. the LEDS are 12v with built in resistors. here are some updated pictures and a link to a short video of it:

Make sure the resolution is 1080, I think I defaulted it at 360 by accident

#### Attachments

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Jul 7, 2015
3,285
Nice job!

#### hevans1944

##### Hop - AC8NS
Jun 21, 2012
4,780
Beautiful! Excellent project, well done.

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