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Georgeo
07-12-2004, 03:57 PM
Anyone ever seen a set of plans for an anemometer and the electronics for a read-out? I have pretty modest skills sheet-metal wise, and my electronics stops with a 6SN7, but I can learn!! Thanks for any helg
George

Mike Burdick
07-12-2004, 04:46 PM
George,

http://www.energyquest.ca.gov/projects/images/anemo-meter.gif

Just kidding!

Here's a link that might be helpful:

http://www.alphalink.com.au/~derekw/ane/anemain.htm
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[This message has been edited by Mike Burdick (edited 07-12-2004).]

Tony
07-12-2004, 04:55 PM
hey george,
i've got a bit of experience on this one as i'm living in windfarm country. let us know a bit more about your anemometer and specific questions you may have. as with most any product, you're looking into a huge range.. from pinwheels to $1000 instruments.

testing a potential wind site? putting together a weather station? just looking for an interesting project?

your sheetmetal skills might better suited to sheet-plastic here.

regards,
-tony

Evan
07-12-2004, 05:13 PM
I built one years ago. I used the plastic eggs that women's nylons come in for the cups. It uses an optical interrupter that interrupts once per rotation. I designed the electronics myself, I may still have a copy of my schematic in my files. It has a three digit LED readout and uses a simple counter chip and some seven segment latched drivers. The counter starts each rotation and counts down from max which is 256. The longer it takes for the next interrupt the lower the reading. I calibrated it by attaching it to my roofrack and driving at various speeds in both directions. The entire unit only cost about $30 to make and even has auto display dimming. I'll have a look tonight to see if I can find the schematic.

Another method to consider is a hot wire anemometer. This is dead easy to experiment with. Break the glass from a 12 volt light bulb without damaging the filament and run it on about 3 volts or so, just enough that it barely glows deep red in the dark. The current flow will be proportional to the wind speed.

[This message has been edited by Evan (edited 07-12-2004).]

RobDee
07-12-2004, 07:24 PM
Take a look at the OtherPower board. Lots of people are using small DC motors with easter egg cups. Measuring the voltage from the motor with a digital meter. The motors are pretty linear.
I'm in the middle of a design for my site but it goes beyond simple electronics other wise I'd post it although if anyone wants I'll shoot the schematic out.

gunsmith
07-12-2004, 08:24 PM
Thanks for the laugh Mike. I don't know why it struck me so funny but it did. Tears still streeming down. http://bbs.homeshopmachinist.net//biggrin.gif

Evan
07-12-2004, 10:17 PM
Georgeo,

Here is the schematic. It uses a handfull of cheap TTL chips. The head unit uses an optical interrupter that should be powered by a separate 12 volt supply with appropriate current limiter resistor on the led and a 10k pullup resistor on the phototransistor. The design uses an opto isolator to prevent lightning induced surges in the cable from frying the electronics in the readout. The cable from the head should be shielded with three wires in the shield, 12V, Signal/LED ground and Signal. The shield should be separately grounded.

Oops, I just went and had a look at the encoder head. I don't use it anymore as my property here is too well protected by trees. The encoder generates 32 pulses per rotation. The slower it goes the lower the count per unit time. The counters are reset by the 555 timer which also controls the latch (store) input of the seven segment drivers. The first 555 timer controls latching of the count. The second is wired as a one-shot triggered by the first that produces a reset pulse for the counters just after the store pulse. The 100K trimpot on the first 555 timer is the wind speed calibration resistor. The unit updates about once per second. Not shown in the drawing is the auto dimming circuit. That is a third 555 timer that pulse width modulates the display power with a simple photoresistor on the 555 timer. Also, the circuit as shown has a 10x/1x switched divider for low/high wind speeds. When in 1x mode it displays to the nearest XX.1 mph. Also not shown is a simple switch that allows two different calibration trimpots to be switched in for MPH/KPH readings.


This is basically a thumbnail, click on the link for the high-res readable copy (about 300K).

http://vts.bc.ca/img/anemometerthm.jpg

right click here to download the full size image:

http://vts.bc.ca/img/anemometer.jpg


[This message has been edited by Evan (edited 07-12-2004).]