Weatherstation problem

The plan was to build a mobile weather station with an arduino, two old windspeed sensors from the local paragliding school, a temperature sensor, a solar panel and an old cellphone.

As the first part I wanted to read the anemometers. I got them for a bargain from Touch&Go. Only I couldn’t figure out how to read them. It was no simple switch, so I suspected a hall effect sensor. From Flytec I got a schematic how to make the circuit. On the breadboard it worked immediately, but on the PCB, I got no readings. After a bit of measuring and thinking, I added two more resistors, to have the oscillating voltage pass the reference voltage.

Next, I started to calculate the wind direction from the two sensors for X and Y direction. Only then I realized that the windspeed alone is not enough. I would need a sign (+ or -) meaning if the wind blows from the front or back through the sensor. With only the speed I know only the angle but not which quadrant. And the quadrant is actually more important than the angle for me.

Ideas are welcome…

Arduino proto board