Rainfall Gauge using Hall Sensor

This is one I was working on a while back but have put on hold.  I have a working prototype so will post it anyway - maybe it will inspire me to finish it up.  Find photos below and preliminary code here at github.

The sensor works by collecting rain in the funnel as shown in the top photographs.  The funnel has a known diameter and thus area.

The rain then collects in the rocking mechanism in the middle photograph.  The pivot point for the mechanism is better seen in the top photo.  The volume collected can be calibrated by moving the adjustment screws up and down. The hall sensor is the device that has been attached with yellow wire.  It is opposite the South pole of a small round magnet in the middle photo.

When the tipping mechanism fills it tips as shown in the bottom photo. The hall sensor loses contact with the magnet and reports the change to the MSP430F5529 microcontroller.  The water then drains out the bottom of the sensor through holes.

The sensor works and appears to be accurate and repeatable.  I have not kept it in service long enough to comment on how reliable it might ultimately be.  I need to go back and clean up the design a bit and incorporate it into the larger weather station vision I have.

Credit to msuzuki77, the Lazy Old Geek
http://www.instructables.com/id/Arduino-Weather-Station-Part3-Rain/
for the inspiration for my version