Where has the time gone?
I spent about 3 months collecting components and researching sensor designs for my weather station project. Sadly, after I collected what I needed, RL struck and they now sit in a box. š
Just before the holidays, I found a portable weather station on clearance at Big Lots. I couldn’t pass it up for $20. It’s pretty much a toy, but it has been fun to play with! I thought I might hack it for the sensor parts and short cut my project, but I decided it would be better to use for calibrating my actual project. It just isn’t heavy duty enough for long term use.
A couple of weeks ago, I built a little anemometer using my LEGO Mindstorms NXT and some extra parts. I borrowed the initial design from a project on NXTLog. The original design had poor resolution because the light sensor only measured rotations in 180 degree increments. By using the RCX Rotation Sensor and a 1:5 gear ratio, my final resolution was 4.5 degrees. My simple gearing mates a 40 tooth driving gear with an 8 tooth gear. I originally attempted a complex gear train with a ratio of 1:15, but there was just too much friction and I couldn’t get it to spin below 6-7 MPH.
It came out pretty nice. I calibrated it using my toy anemometer and a box fan. I determined there are 32 increments per MPH. I left the light sensor on since it is completely passive and doesn’t interfere with the mechanism. This one isn’t suitable for the long term project, but it was a fun diversion.
