ProdMod ™

I have been thinking about brushless motors for a while now, and I wanted to replace a small brush motor with a brushless one but wasn’t sure how to go about it. I looked up how they work to refresh my memory, then I thought I might make one out of permanent magnets and a few coils, but how was I going to control the switching of the coils? If I did use some kind of IC chip to do the logic it would add cost. Then I thought maybe I can just use some kind of analog circuit. Like maybe an infrared sensor tied to a transistor to time the pulses, or maybe a hall effect sensor. So Looked up “simple brushless motor” and found this site. It shows you how to make your own with all those sensors including a reed switch, pros cons etc.

I started to feel like making my own would be a pain and not efficient anyway, so I tried to think of a brushless motor I could find around the house and remembered that PC fans are brushless. I was pretty sure the PC only gave a voltage to the fan and did not offer any pulsing, so the motor must have some logic circuit built in. Perfect. I looked for photos online of PC fans opened up but a quick searched turned up nothing. I don’t know if a PC fan has enough power for what I’d like it to do. But I knew I was ready to take one apart.

So I found an old PC fan that I am pretty sure didn’t work and went at it.

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I came across this lil cutie while looking for a vacuum. It’s made by Trudeau (which makes other interesting devices) and is sold at BedBathandBeyond for only $9.99. So of course I had to pick one up, see if it works then see how.

When I got it I was pretty skeptical. The bristles looked like they were just for show and the fan didn’t look too menacing. Not to mention the small motor and 2AA batteries it was driven by.

So I got some crumbs off a Thomas’ English muffin and dropped them on the floor and gave it a try. At first I lightly passed it over the surface and it didn’t pick up much. But then I applied just a slight down force to bend the bristles and bring it closer to the surface and it sucked everything right up. You could hear the crumbs wacking around in the thing. So I was impressed. Not sure if I would actually use it, or why you need one but it works and works pretty well. Clean up is easy you just pull off the bottom and dump it.

Here is a quick video to see and hear it pick up the crumbs

And here is a video of me opening the vac to show the crumbs inside. I promise its not a camera trick. The original file was too long so I split it into two movies.

Ok now here’s a look inside the product so you can see how it works. My favorite part.

INSIDE THE CRUMB VAC

First a shot of the packaging. Pretty simple and affective, you can see what I paid for it.

It actually came with no instructions. Nada. I guess you dont need em. Well you first have to figure out how to open it. You know 2 AA batteries have to get in there some how.

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.The first thing I did was I tried ot twist it open. By doing that I was able to remove the top cover. Then you see the battery holders

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Then I realized there are two tabs on the sides you use to unlatch the bottom cover brush part. I was able to see the impeller and the cup that holds the crumbs.

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Here is a close up of the Battery holders. You can also see the electric motor which is a simple brush electric motor. You might find these motors in any small toy car. They are very cheap but work very well, and are easy to find.

You can also see how the switch is designed. Its a simple set of thin flexible metal strips that are close to but not touching the contacts on the base. When you push the white plastic button on the top housing it makes the contact and completes the circuit. This was a smart way for them to save cost and assembly time as compared to using a small momentary switch which has to be mounted and soldered to wires.

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Here is a look at the impeller housing and bottom housing to see how they interface eachother.

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The impeller cover is easily popped off in 4 places revealing the impeller. The impeller rotates in a clockwise direction in this view.

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Part Scavengability:
I guess there are a few parts here to take, but its so small you might just want to add to it instead of taking parts away from it. Here is a list.

• Mini Vaccum - About 3″ diameter
  • Motor - low power/high speed
  • Impeller - I havent tried to remove it yet, but you should just be able to pull it right off
  • Filter
  • Switch - Simple metal contacts
  • Battery tabs
  • Battery holder- 2AA
    • battery tabs
    • wires
• Bottom housing, round
  • Bristles
• Top Housing, round
  • button - round

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Summary

Pros

I think its a great design. Its simple, cheap and it actually works!
For 9.99 you get a motor and impeller assembly.
I think its hackable.

Cons

Power- medium suction.
Noise - a bit noisy and whinny

Modification Wishlist

1. I would like to replace the motor with a quiet high efficient one.
2. I want to make a simple low power floor vac that scurries around and picks up dust and crumbs. I think this mody can be used together with another drive motor, wheels and some logic.

Potential value adder- Original cost $9.99

1. I would pay an extra $10 for it to be quiet.
2. I would pay $30 to $50 for a wheeled floor crumb cleaner.

Can you think of another use for these parts? Or another mod to this product.

Sumbit your prodmod idea in the comments below!