Smallest DIY Mini Motor Yet?




About: Like inventing, woodworking, tractor gadgets, gardening, making Youtube videos, wind turbines, ham radio, making instructables, etc

Not totally sure how to properly classify this Instructable as it could fit in the "props" section or in the "offbeat" section or maybe in the "pranks" section - but because the motor is fully functional it might even fit in the "energy" section. My earlier Instructable 3 mini motors gives details on how to make a motor like the one shown in the video.

First take a look at the short video (below) before peeking at the text and steps that follow.

Step 1: Please Take a Look at the Video First

The idea with this instructable and video was to create a basic illusion. In other words I wanted to give a false impression to the viewer of what the objects are in terms of size, shape and to some extent function.

The fake pencil is far from perfect - but I'm definitely curious about initial impressions by those of you who viewed the video.

Did the illusion work?

Step 2: Finding Replica Large Penny and Comparing With Standard Penny

So if you checked out the video you know that I used a LARGE replica one cent piece or penny, and I made a fake LARGE pencil.

I bought the large replica penny when visiting the gift store in the California State Capitol building. I'm guessing these replicas might also be available in other state capitol buildings and perhaps in tourist type stores, or on line. I paid about $3 for one penny :).

Step 3: Making the Large Fake Pencil

I had a short length of 1-1/8 inch diameter hardwood dowel on hand that worked fine for the fake pencil. I didn't make any attempt to perfectly scale the large pencil with the standard pencil - just went by how it looked. Power tools made quick work of shaping the pencil but it wouldn't take much longer doing the shaping with hand tools (small hand plane and sandpaper for example).

After shaping the pencil point I painted the body with yellow spray pain. (I first protected the shaped point with masking tape.)

A black ink Sharpie permanent marker took over to simulate the "lead" of the pencil. The ink was a bit flat looking so I went over the Sharpie ink with a regular lead pencil to give it a slight glossy look.

A bamboo skewer stood in for a standard toothpick - I started the video by showing a real tooth pick being selected from a toothpick container. The next shot in the video shows the skewer giving the motor a flick to get it started (all part of the illusion of course).

Step 4: Tried Homopolar Motor First

My original intention was to make up a small homopolar motor for this instructable. I had problems getting the motor to rotate well enough for a video - so I switched to the motor design shown.

The other photo in this step shows how I was able to keep the operating motor on the large penny while manipulating it in my hand. The larger neodymium magnet on the underside of the penny kept the operating motor very stable and it also made it easier assembling the motor while on the penny. The penny is non magnetic.



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    34 Discussions


    4 years ago on Introduction

    Fooled me, but the lack of shallow depth of focus typical for such a "closeup" was strange. Don't know how you could have simulated the small range of focus you would need to improve the illusion though. You would not have shown the choosing of a toothpick except to establish the scale of the prop. That was so unusual (to me) and brief that it didn't fully register what it was. It also seemed odd to switch from a toothpick to a pencil for no (then) apparent reason. I was so eager to find where you found such a tiny battery that I didn't dwell on the surreal aspects of the video. It was brief enough to preclude me from becoming consciously suspicious. It's only during subsequent viewings that the big pencil and penny appear imperfect. Love it. So clever that I want to check out everything else you have done.

    2 replies

    Reply 4 years ago on Introduction

    Thanks for the comments and analysis denbecr! It's clear that you are much more tuned in to the technical considerations of this kind of project project than I am. My camcorder was set on auto all the time (as it usually is). This was my first illusion video effort - the closest I've come to it since is this video about the Drone at the White House.


    4 years ago

    Haha this is sweet, knew the pencil looked 'off'

    1 reply

    They did an amazing job with the replica penny - just some mold marks around the periphery. You can see this in the last picture of the instructable. Thanks!