Assemble the Tachometer and discover how it works. The model kit comes with a QR-code to the study guide about the mechanism, the principal of its working, the main characteristics, formulas. It also includes interesting assignments. Dive into augmented reality and look at how the Tachometer works. Interact with the model via a special AR application from Ugears. A tachometer is a device designed to measure the rotational speed of various parts in engines and other mechanisms. It calculates revolutions per minute (RPM). The tachometer also measures and monitors load limits, in order to decrease or increase RPM so that the engine or mechanism runs within its optimal parameters. Who invented the Tachometer, and when? The tachometer was invented by the German engineer Dietrich Uhlhorn in 1817. His invention was a special device that measured centrifugal force. From 1840 on, this device has been used in railway locomotives, and later in cars and all manner of vehicular transport.