Release Of Pressure Detonators ------------------------------ The next type of detonating device I will discuss is called a releas-of-pressure mechanism. This device employs exactly the same principles as the pressure-trigger device, except in reverse. The movement of the pressure plate, rather than down, is now up. This can be used effectively when a weight is placed on the pressure plate. Then when it is removed, the explosives will be ignited. To construct, use a heavy-duty spring beneath the first metal plate. Connect a wire from the blasting cap to the first metal plate. The second wire is then stretched from the bottom of battery "A", to the second metal plate. The third wire is run from the electrical blasting cap to the top of battery "B". When this is accomplished, the booby trap is fully cocked. When the weight on the pressure plate is remove, the spring will will force the second metal plate against the first, thus completing the electrical circuit and exploding the device. In a tension-release booby trap, when the tension, resulting from a wire pulling on a pliable metal strip, is released, the metal strip will snap back into another metal strip. Since the wires from the batteries and blasting cap are connected to either metal strip, when they touch, the circuit will be complete and it will detonate the explosive charge. This type of detonator is especially effective when attached to drawers, doors, or any movable object. **************************************************