We present here a method of measuring the EAG of a silkworm moth with a wireless telemetry system. Using a radio telemetry system, it is possible to obtain the EAG under free walking. As for Electromyogram(EMG), the telemetry is often used to get the signal during the free-flight. Now, we improved the EMG telemeter for EAG measuring. The telemeter for EMG doesn't have enough input impedance to measure the EAG, and it can't send the low frequency signals. By adding an instrumentation amplifier, we got the high impedance, which measured 500 kilo-ohms. Using a sub-carrier modulator, the telemeter can send signals in the low frequency band, from 0.1 to 30 Hz, which includes the frequency band of the EAG. Using surface mount devices, the telemeter was made so small, 0.5 mm², that a moth can carry it on its back, and walk freely. The weigh of the telemeter is about 0.2 g without batteries. The telemeter is driven at 3 V.

References :
Masaki Shuzo, Kiyoshi Matsumoto, Isao Shimoyama, “Remote Inductive Powering for EMG Telemetering,” International Workshop on Power MEMS (PowerMEMS '02), Tsukuba, Japan, Nov. 11-12, 2002.