Working with small motors

[djgra79]

For this Halloween i'm looking to make a Flying Crank ghost such as this:
View: https://youtu.be/pMh0LCJqYro


Last year I bought some small geared motors such as these: http://www.ebay.com.au/itm/New-Reve...hash=item5441358139:m:my-_Pm2E2st6mNBnLGtbxOg
As you can see they have D-shaped drive shafts but being small I have no idea how to mount a bar to these so it can operate as per the video. I also will use these motors for small swaying foam tombstones, but again due to the D-shape shaft I cannot get anything to stay on it.
I bought these also last year http://www.ebay.com.au/itm/RC-Car-S...253630&hash=item33d0e310b8:g:DcUAAOSwvjdZQ3iX but they are so small I cannot really use them well to mount anything to.

Open to suggestions pls

 

[diyer]

Hi Digra,
So you just want to add a crank to your motor? Send me a pm, I'm happy to make them for you. Just need the shaft size and the length of the crank you need.

 

[andrewa]

I purchased these Aluminium mounting hubs from little bird electronics it worked a treat and had heads and skulls bouncing up and down

 

[djgra79]

Ah great. Thanks for the offer diyer but I'm not 100% sure of the dimensions I need.
I think Andrew's suggestion will possibly better suit.

 

[andrewa]

Just let me know if more detailed pics are required.

 

[djgra79]

Hi @andrewa - can you please show me a close up on how you attached wires to your motors? I've got the mounting hubs and they work well so far, next step is wiring. Thanks.

 

[andrewa]

Slid on heat shrink on to the wires, threaded the wires thru the small holes on the tabs on the motors, first folding the tabs out as they had been squashed flat on the motor, then soldered the wires on, and then covered in heat shrink


Just note, the tabs were folded flat.

 

[marmalade]

Stepper motors are a far better option for moving displays like this... not only do they have tons more torque at lower rpm but their positioning and speed is (of course) absolute and infinitely variable. Plenty of cheap drivers out there now and there's even some p&p dmx stepper controllers available which makes it a breeze. And lots of off the shelf hardware, nema23's generally have a 1/4" shaft which accept a huge range of couplings

And they never wear out!

 

[David_AVD]

I've never been successful using a stepper motor without some sort of gearing.

 

[djgra79]

Well after tinkering this afternoon, these small geared motors don't have enough grunt to operate the FCG (flying crank ghost)
So I'm now in the market for some car wiper motors :/
I'm pretty confident that the small motors will be able to animate my tombstones such as this:
View: https://www.youtube.com/watch?v=mDT4Xv3Kf7w

 

[marmalade]

I've never been successful using a stepper motor without some sort of gearing.

An average nema 23 is rated @ 180-250 oz/in, the dual stacks are over 400 and capable of ripping fingers off

But yes, it certainly depends on the load, a geared stepper would still be far more powerful than a similar sized geared brushed motor at low rpm, and have substantial advantages in precision and low cost control.

 

[djgra79]

An average nema 23 is rated @ 180-250 oz/in, the dual stacks are over 400 and capable of ripping fingers off

But yes, it certainly depends on the load, a geared stepper would still be far more powerful than a similar sized geared brushed motor at low rpm, and have substantial advantages in precision and low cost control.

I have no real idea what you just said

 

[djgra79]

So I have whipped up a quick proof of concept test for the small geared motor to rock the tombstones. Success!

View: https://youtu.be/scKxhCA8Uuc

I will replace the corflute with a small piece of timber, or possibly a piece of conduit or metal make-a-bracket, to keep the weight down. This was more to get the sizing for the linkages.

 

[David_AVD]

That looks great. The only problem I can see is that I need to make one now! lol

 

[djgra79]

That looks great. The only problem I can see is that I need to make one now! lol

Wow, I must have done good if YOU are copying ME for a change!!