Digital rotation meter

There was developed a digital universal measuring device for the rotation frequency of various parts: a gear wheel, a splined shaft, a special disc with slots, etc. The use of a 16-digit summing electronic counter makes it possible to form a digital code up to 65536 pulses per second, which makes it possible to install it on almost any vehicle. At the same time, it has simplicity, low cost, reliability and accuracy. The design of the meter includes a signal transducer, a self-oscillating multivibrator, logic elements, and an electronic summing pulse counter. The sensor of the meter is made in the form of an inductance coil with a magnetic core. The first differentiating circuit with a diode is used as a converter of the sensor signals, connected to a logic AND gate, which is connected by its output through a resistor to the counting input of the counter. The input of the second differentiating circuit and the second input of the logical element AND are connected in parallel with the output of the self-oscillating multivibrator, and the input for setting the zero of the counter is connected in parallel with the output of the second differentiating circuit. The self-oscillating multivibrator is symmetrical, and the resistance of its resistors and capacitors are selected in such a way that the formation of rectangular voltage pulses and pauses duration of 1 second at its output is ensured. The presence of a sixteen-bit summing electronic counter, consisting of 16 triggers and having 16 outputs and 16 light-emitting diodes, each of which is connected to one of the outputs of the counter, allows, when the meter is turned on, to receive digital codes at their output in one second, showing the speed. An example of calculating the elements of the differentiating circuit of a multivibrator is given. The experiments have confirmed the efficiency of the developed rotational speed meter.