Cheapest anemometer

[domwild]

As it was printed in an Oz magazine it is not something available in the wide world, so here it is:

Two ping pong balls split and connected together on horizontal cross.

Vertical shaft to have model car bearing mounted on pill container, shaft also contains magnet for reed switch.

Reed switch stuck to pill box is wired to equals sign (=) on calculator.

Calculator to have connection to larger battery for constant use.

Calculator must be old type WITHOUT auto-power off option.

When you put one plus (1+) into a calc and then repeatedly press the equals sign you will notice the screen to start counting, i.e., 1,2,3,4,5,..... Just what you want.

Calibration via car tacho as with a wind mill.

The only problem I can see that even the cheapest calculators these days seem to have an auto-power off option.

Hope this is useful.

dominic

 

[bob g]

pretty cool idea, only on question to clarify

what is the calibration method?

can you give more detail on the calibration, i am not clear how to use a car tachometer?

bob g

[JeroenH]

can you give more detail on the calibration, i am not clear how to use a car tachometer?

Sounds te me like they stuck the anemometer out of the window of a moving car and calibrated it with their speedometer. Wait for a day with little or no wind, do a few runs in opposite directions (to cancel out any wind factor) and you should have it pretty well calibrated.

Of course, you should calibrate your speedometer as well, as most (on European cars, at least) tend to underread by about 10%.

[laskey]

I take my GPS with me.  If the signal is good, it will tell you fast you are going, with a fair degree of accuarcy.

Cya,

Chris

[test lab guy]

Another method that works:  Get a DC powered computer fan, not the tiny CPU fan, but a 3" chassis fan.  For a DC fan, you should be able to notice a slight amount of cogging when you turn the blades. Remove the blade and spindle to access the circuit board.  Cut the DC input wires and reconnect to the wires from the stator.  The one I modified had 3 wires, 2 ends and a center-tap, the largest output is on the 2 end wires.  Relpace rotor.

To obtain the best output, face the exit side of the fan upwind.  If there is an air flow arrow, the wind through the fan will now be in the opposite direction.

The center flat disk of the fan, facing up wind, will need a hemisphere glued to it for proper air flow into the blades.  Use whatever you can find that fits.  A ball from a roll-on deoderant may work.

Connect the output to a hand-held DMM that has frequency function.  Thats it.

I got very linerar results from 6 to 27 mph.

mph = freq * 0.155 + 5

TLG

[troy]

May people have also had good luck with modifying an electronic bike speedometer to give you a readout in mph or kph (they all have provisions for changing "wheel size" to calibrate them).  The anemometer cups would work the same as the first description, but this would take care of all the elctronics and they often have useful cumulative data avialable as well.  Locally, they're less than $20 US.

Best regards,

troy

[Norm]

  I posted this about a year ago if anyone on this post remembers about this little trick with the calculator.....

http://www2.suite224.net/~peppysue/Projects.html

or the oldersite

http://www.fortunecity.com/marina/titanic/664/id6.htm

 for a coil-winder but would also work for an anemometer...works best if you make larger cups with a cam operated push rod to activate the ='s button, the newer ones shut off automatically after about 5 minutes... calibrate by seeing how many turns it makes in a 5mph wind or just do the math with the calculator. Looks like a nice continuation on my Projects in my new little website as above.

              Fun Fun Fun!

          ( :>) Norm.

 

[elvin1949]

i gave 10 bux at wallyworld