A Passive Micromechanical Counting Mechanism

We present a passive micromechanical counting mechanism intended for monitoring of critical threshold violations, such as mechanical shocks or strain violations. The presented microsystem allows to count up to 64 (6 bit) threshold events without requiring electrical energy. Featuring a micromechanical A/D converter, the memory can be read out electronically at any time, e.g. by means of RFID. We show that for an incrementation of the counter, either a force impulse of
$\boldsymbol{750\ \mu} \mathbf{N}$
or a displacement of
$\boldsymbol{5.5\ \mu} \mathbf{m}$
is required.