Well I tried using coins with not much luck.
I tried using 21 nickels (to calibrate it to 100 grams) which is about 98.7g if a nickle is said to be 4.7g's
Anyway, this calibration failed, so I tried using 20 nickels and 2 dimes, just to up the weight a bit hoping to get it closer to 100g's and pass the calibration test. This also failed. So apparantly I need exactly, or amazingly close to 100g's of weight to calibrate.
Does anybody know any combination of coins to hit 100g's exactly?? :P