A highly reliable fuse for explosives and armaments is achieved by employing a micro mechanical device that operates to disrupt a relatively low impedance bypass circuit coupled in parallel with a relatively high impedance trigger mechanism. The removal of the electrical bypassing is performed as a result of the movement of the micro mechanical device to enable detonation under prescribed conditions. The electrical bypassing is removed by having at least one low impedance electrical bridge that is part of the bypass circuit break when the micro mechanical device is subjected to prescribed trigger activation forces, which are typically large forces, such as are generated during launch or impact. The micro mechanical device may be a micro-electrical mechanical system (MEMS) device and the bridge is at least one spring that is part of the MEMS device and also part of the bypass circuit.