## Step 4: Making the Ball-bearing Supported Shaft 2

Now you will need something to hold the bearings and shaft. You might be able to find something at the hobby shop which would work. But at worst, just find a block of aluminum, plastic, or wood which is about 1" diameter and 2" long. Drill a hole all the way through the long way, larger than the shaft but smaller than the outside diameter of the bearings. for example with bearings that have a 1/8" ID and 3/8" OD, i drilled a 1/4" hole so the shaft won't touch it. Now at either end of the block drill a 3/8" hole right on top of the 1/4" hole, but only drill in about 1/4" (far enough for the bearing to fit into the block.
<p>how can i get the schematic diagram from your given figure ?</p>
<p>You can also find the relation between RPM and wind speed in the specification guide of the Davis anemometer (where the cups come from)</p><p> 1600 rev/hr = 1 mph</p><p> V = P(2.25/T)</p><p> V = speed in mph</p><p> P = no. of pulses per sample period</p><p> T = sample period in seconds</p><p>Then if you know the wheel diameter used by your bike meter, you have everything to deduce the wind speed, you don't need to calibrate it.</p>
<p>lolol</p>
<p>http://www.davisnet.com/product_documents/weather/spec_sheets/7911_SS.pdf</p>
while it looks fun to build I bought one from Ebay and it was 20 bucks. I love to tinker but sometimes you just cannot beat the Chinese for price...<br><br>
I had another thought.&nbsp; I read elsewhere that after a while the reed switches will wear out especially if you leave the sensor up all the time and live in a windy area.&nbsp; Seems to me it might be possible to use a magnet and a hall effect sensor.&nbsp; <br /> Thoughts?<br />
Good project!<br /> The bearings are called: Sealed Bearings -- consisting of numerous ball bearings, encased in a metal cartridge.<br />
You could also... duh... use another bike computer and ride around the block and compare the values. GPS is also a possibility in that regard. On the other hand to average out any values to account for any wind, using cruise control in the car might be helpful, but using GPS to nail your speed would probably be best.
Hello, I am interested in making this anemometer, but i was looking on the Davis site, and they have 4 differnt wind cups. 2 different sizes for the part #07903, but small size or large?
Out here where the owls get the chickens. Some build whirligigs out of bike wheels a cream separator plates. I have toyed with the idea of using a bike wheel and axle for the rotor. That way the digital read out could be used as is, using no math.
When counter-boring holes, if you drill the larger holes first, it's a snap to have the smaller one be concentric, as you'll still have the bottom of the hole, and it will have the center point ready-marked and "center punched." But you knew that already, yes?
you need to drill the small hole all the way through first. if you drill the two large holes part way, then try to drill the small one from one end, it is never going to end up at the exact center of the big hole on the other end.
Aha, looks like I was not paying enough attention. I was thinking of drilling from one side only. I figured you knew better. ;-)
Ummm, "Ball" bearing? You sure about that?
Very cool, elegant in it's function & simplicity. This would go well with a digital weather vane a friend built using a nifty bcd encoder (to support the vane & read it's position) feeding a bcd-to-octal or -hex decoder which lit LEDs set in the compass rosette pattern. (Sadly, I've been living vicariously through other peoples projects, that's why I was so happy to stumble on this site.)
An idea for home-made wind cups...those plastic easter eggs that break in half have a nice parabolic shape that could work. Their strength and durability might be questionable, and I haven't come up with a mounting design yet but it might be a start. Actually, it would probably be easier to use a more durable plastic ball. I plan on doing a quick test using plastic "k-nex" toys or legos.
This is a great idea! I have found that a wealth of miniature ball bearings can be had from salvaging discarded VCR's and hard disk drives.