USB Freeduino (Arduino-clone) $22.50
Adafruit Data logging shield $19.50
SD Card $ 6
Aluminum NoTrespassing Sign $ 2
2 Ethernet Couplers $1.40 (ebay.com)
1 empty Cashew nut plastic jar
1 Funnel (5.5" diameter) dollar store
1 ¾” pipe strap $ 0.59
2 #8 nylon washers $ 0.17 @
1 small magnet (10 for $1 at Harbor Freight)
Honeywell SS461C Hall Effect IC $1.86 Digikey
Prices US dollars March 2011
Rotary tool (Dremel/clone)
Any USB Arduino should work but it is easier to wire it up to an Arduino shield so the clone would have to be shield compatible. There are some good deals on ebay for Arduino Duemilanove 2009 for about $18.
The syringe is actually a cattle syringe for veterinarian use. I am a vet, close enough. Actually, this worked pretty good for calibrating my rain gauge.