Weekend stuff
Jan. 13th, 2008 08:51 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
johnridleyTom and I built a model electric motor for his science fair project. We still have some work to do. Hard drive magnets are not ideal for a large motor, because they're just too small. We went to Harbor Freight and found a welding support magnet set which consisted of two 2"x4"x.75", 50 pound pull ceramic magnets in a bracket for $7.99; a bargain! They got the motor working pretty well. The only problem now is that it won't self-start; the attraction to the steel bar of the armature is too strong for the electromagnet to overcome, and I don't think we should run any more voltage through the wires or we might fry the windings (we salvaged the wire from the head actuator coil of the 4G hard drive we stole the original magnets out of). We picked up the magnet wire assortment from Radio Shack while we were out so I think we need to put more windings on that coil. The thinnest wire in the set is a fair amount thicker than the hair-thin stuff we've used so far. Also I think maybe we should shorten the armature.
We also made the "Beakman's World" electric motor, which is just some magnet wire, a magnet stuck to a C cell, and a couple of paper clips. Actually we made two; I made one just for fun while Tom was over playing Wii next door this afternoon, then Tom saw it when he came home and wanted to make one himself. They're a little fussy to get going but not bad.
I also found that Harbor Freight's cheapest reflective vest is also by far their best; $4.29 buys a vest with some damn good reflective stripes on it. Anyone who runs or cycles at night should grab one or two.
On the left is my old reflective vest, on the right is the new one. Photo taken at night from 120 feet away, with a point-n-shoot camera with a flash that's only supposed to be good for 10 feet. As you can see, this stuff is more reflective than anything else in the photo, including the license plate and the car reflectors.
It looks like 3M Scotchlite, but it's probably a Chinese clone. Seems like good stuff though.
Both vests come from Harbor Freight; oddly enough the good one is $4.29 while the other is $5.99.
We also made the "Beakman's World" electric motor, which is just some magnet wire, a magnet stuck to a C cell, and a couple of paper clips. Actually we made two; I made one just for fun while Tom was over playing Wii next door this afternoon, then Tom saw it when he came home and wanted to make one himself. They're a little fussy to get going but not bad.
I also found that Harbor Freight's cheapest reflective vest is also by far their best; $4.29 buys a vest with some damn good reflective stripes on it. Anyone who runs or cycles at night should grab one or two.
On the left is my old reflective vest, on the right is the new one. Photo taken at night from 120 feet away, with a point-n-shoot camera with a flash that's only supposed to be good for 10 feet. As you can see, this stuff is more reflective than anything else in the photo, including the license plate and the car reflectors.
It looks like 3M Scotchlite, but it's probably a Chinese clone. Seems like good stuff though.
Both vests come from Harbor Freight; oddly enough the good one is $4.29 while the other is $5.99.
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photos, we demand photos...
Date: 2008-01-14 05:17 am (UTC)