The core element of the anemometer is a metal rod from a ballpoint pen. In the lower part of the rod (where the plug was inserted), I inserted the disk from the mouse (encoder). In the design of the mouse itself, the lower part of the encoder rested against the body of the mouse to form a point bearing, there was lubrication, so the encoder spun easily. But it was necessary to fix the upper part of the rod, for this I picked up a suitable piece of plastic with a hole exactly along the diameter of the rod (such a piece was cut from the carriage extension system CD-ROMa). It remained to solve the problem so that the rod with the encoder did not fall out of the point bearing, so on the rod directly in front of the retaining element I soldered a few drops of solder. Thus, the rod freely rotated in the holding structure, but did not fall out of the bearing. The reason for which the scheme with the encoder was chosen is as follows: all articles on home-made anemometers on the Internet described their production on the basis of a DC motor from player, CD-ROM or some other product.The problem with such devices is firstly in their calibration and low accuracy at low wind speed, and secondly in the non-linear characteristic of wind speed with respect to the output voltage, i.e. There are certain problems for transmitting information to a computer, it is necessary to calculate the law of voltage or current change 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, which contains a microcontroller that counts the number of pulses per second on one of the ports and outputs this value to the USB port, is somewhat more complicated. &Nbsp; 4.
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