DIY wind speed meter
There was a task to collect anemometer for one project so that it was possible to take data on a computer via USB. The article will focus more on the anemometer itself than on the data processing system from it:
So, for the manufacture of the product needed the following components:
Mitsumi Ball Mouse - 1 pc.
Ping-pong ball - 2 pcs.
A piece of plexiglass suitable size
2.5 mm2 - 3 cm copper wire
Ballpoint pen refill - 1 pc.
Chupa Chups candy stick - 1 pc.
Cable clip - 1 pc.
Hollow brass barrel 1 pc.
2. Production of the impeller
I cut the tube from the candy into 3 parts about 2 cm long.
I cut 2 balls in half and with the help of small screws from the same player and polystyrene glue (glue gun) attached the halves of the ball to the tubes from the lollipop.
He put the tubes with the halves of the ball on the soldered pieces of wire, and fixed everything on top with glue.
3. The manufacture of the main part
The reason why the scheme with the encoder was chosen is the following: all articles on home-made anemometers on the Internet described their manufacture on the basis of a DC motor from a player, CD-ROM or some other product. The problem with such devices is, firstly, in their calibration and low accuracy at a low wind speed, and secondly, in the non-linear characteristic of the wind speed with respect to the output voltage, i.e. To transfer information to a computer, there are certain problems; you need to calculate the law of change in voltage or current from wind speed. When using an encoder, there is no such problem, since the dependence is linear. The accuracy is highest, since the encoder gives about 50 pulses per revolution of the axis of the anemometer, but the converter circuit is somewhat complicated, in which there is a microcontroller that counts the number of pulses per second on one of the ports and sends this value to the USB port.
4. Testing and calibration
A laboratory anemometer was used for calibration.