Faraday cup. Just two coaxial aluminum cans (100 pF) insulated by ceramic stands, with a BNC socket soldered across them. Even without an electrometer, TIA or charge amplifier, and under a constant mains hum, I still got an obvious signal with just a 10x oscilloscope probe - works surprisingly well for the crude setup. Got positive pulses for glass, negative pulses for plastic. Unfortunately the cans are painted, so I can't show discharges by contact like the original Faraday's ice pail experiment. #electronics