Instructables
Picture of Iphone Windmeter
Simple proof of concept wind meter using your phones compass. The spinning magnets change the magnetic field around the phone which is picked up by your phones magnetometer. 

Check out vavuud website to look at real deal which you can purchase to support the application.  They have tested their one in a wind tunnel so it's quite accurate.
 
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Step 1: Shopping

Picture of Shopping
From you local dollar shop you should be able to get most of the stuff you need.

2 sets of measuring spoons, I used 2 x 5ml spoons.

Neodymium magnets (the shinny strong ones) I got mine out of a fishing game

Small bearings, I got mine for a couple of dollars from a model shop, but you can get them from some toys as well.

A few old pens.

3.5mm headphone jack ( cheap headphone will work)

Other tools you need are scissors, soldering iron, small hack saw.

Step 2: Cutting And Welding

Picture of Cutting And Welding
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Cut the scoops off the 5ml spoons

Find a round plastic rod around the house. I used a thick spray bottle tube. Cut this about 60mm long

Using your soldering iron, weld the plastic parts together as shown. This was the first time I have tried it and it worked ok,

Step 3: Bearings

Picture of Bearings
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My bearings where 10mm outer diameter, 5mm internal and about 3mm high. I used an old pen as the bearing housing. It took a while to find a pen that fit well. I cut the section of pen about 15mm and inserted the bearings, then used the soldering iron to hold them in place.

Using the soldering iron I made two indents in the top of the section which the rod would locate into.

Step 4: Head Phone Jack

Cut the wire off the headset and check for fit in the bearing. If loose pack with insulation tap, if tight scrap a bit away with a knife. The bearing should sit a few mm above the phone.

Step 5: Clean And Paint

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I used a dremel to tidy up the welds, then painted the whole thing it black

Step 6: Magnets

Picture of Magnets
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Attach the magnets to the outside of the bearing housing. They should be attracted bearings so will hold just fine. A drop of glue could be used after testing.
mark.duyvesteyn (author) 12 months ago
The changing magnetic field is picked up by the phones compass/mangometer
Nick7058712 months ago
It's a great concept and good job finding household stuff to build it.

The one from vavuud is neat but I don't see it as more then that. I've seen other measurement attachments for iPhones before but they all have the same problem...the accuracy is never sufficient to meet the standards that they would need to be used in a professional technical field. This flaw, to me, makes them neat, but a waste of money.
Kiteman12 months ago
How does it work?
Kiteman12 months ago
How does it work?