pace counter - counts jumps too!

. counts jumps too! For a change, here is a circuit which is primarily intended for sports people: it can count steps or jumps. From now on, whenever you go through a skipping session in train- ing, this circuit can tell you precisely and at any moment how many jumps you have made. All you need is a cheap LCD (liquid crystal display) pocket calculator, a small piezo buzzer, a type 4066 CMOS IC, and a few other com- ponents. First, the buzzer has to be prepared as it will serve as the measuring detector. Carefully cut away a strip of the plastic housing and glue a small piece of relatively heavy metal (lead or iron) onto the brass mem- brane (see figure 2). Because of the increased inertia of the modified membrane it bends at every step or jump. The consequent piezo voltage generated by the buzzer is applied to the input of the circuit. The piezo signal is amplified by dar- lington pair T1 and T2, the gain of which is preset by P1. When the signal arrives at T3, it is converted int...