Category: construction

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CNMAT resources archive

Berkeley’s CNMAT (center for new music and audio technologies) has a nice resource archive, with pictures.  Useful if you’re looking for electronic parts, microphones, and other things audio-related.  Similar to RISDpedia and ITPedia, among others, very useful.  Thanks to Tom Gerhardt and Adrian Freed for the link.

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Dynohubs: power from bikers

Lots of people are into mechanical generation of electrical power these days, so here’s a nice tip from the guys at Uncommon Projects: dynohubs.  I had a note in my inbox for months that just said “dynohubs, Tarikh.”  So I wrote, and he offered a lovely explanation, and a link:

Dynohubs are cool. They are sort of stepper motors in reverse,
actually sealed in a bicycle hub. They generate AC current which can be
easily rectified and smoothed to DC and (mine anyway) generates nearly 400mA
without significant speed. There’s some minor friction from the magnets but
they’re much better than the old style “bottle” hubs (which are
significantly cheaper).

Dynohub in Uncommon Action!

Perhaps you were asking me because I’ve been meaning to make an instructible
for months about how to power or charge your iphone/device from your bike?

They’re not necessarily cheap. A quick google search for the Shimano 3N71 that Tarikh mentions comes up with prices ranging from $99 – $150.  3W at 6V, that’s half an amp. Not a bad start.

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Surplus Center

Mike Olson likes to move heavy things.  So when he says something like this:

Hands down the best site for finding cheap powerful motors is:

www.surpluscenter.com

You can’t search by torque, but they usually have an excellent seclection of powerful gearheads and linear actuators.

I had great results with one of these guys a while back. Probably bigger than what you need, but produces huge torque with very little current. The only problem is that it’s very heavy.

I believe him.  So if you’re looking for motors that can lift heavy stuff, follow Mike’s lead.

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Thermochromic inks

From Mouna Andraos, some notes on thermochromic inks:
“Basically, the main company in the US seems to be Chromatic Technologies. They have the widest product line and appear to provide some of the smaller resellers as well (they sell minimum by the 1/2 gallon i think). The stuff we have right now is from: Matsui. It’s for screen-printing on fabrics. They also have products specifically for dying and plastics.
“The problem is that all of the products we have come across start with a color and go to clear or to a lighter color when activated with heat (or cold).”

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