Tachometer is a device that measures the rotational speed of any shaft or disc. The unit of the measurement is usually revolutions per minute or RPM. The traditional method of measuring RPM of a rotating shaft was based on velocity feedback concept ...
.. in most PC add-on cards. One more approach is to attach a simple 16-bit counter, such as the CD4040 and CD4520, to your printer port using the necessary buffering and control (Reference 1). In the last two cases, you can exploit a ...
.. by Elite Worm with an Arduino clone, laser, and sensor for about half that cost (Figure 1). You’ll also need a 3D printer for the housing, though you could probably get creative if one’s not available. Рисунок 1. Laser ...