MachTach Machine Tachometer

This Thing documents the MachTach machine tachometer which was a product I used to sell. I have stopped selling MachTach kits so I am now making the design open source so that people can make their own tachometers. Please read the documentation for information on how the MachTach works, how to assemble it, and how to select and use various sensors. The MachTach works with IR, Hall Effect, and gear tooth sensors. The gear tooth sensor is supported for gears with up to 90 teeth.

Here's an overview
The MachTach is a machine tachometer which is used to display the speed of any machine tool in revolutions per minute (RPM), surface feet per minute (SFM), or surface meters per minute (SMM). Machine tool speed is important because it determines how quickly you may remove material, the surface finish, and tool life. Speed or surface feet per minute should be chosen based on the material, cutting tools to be used, and surface finish desired. MachTach requires only a simple sensor to make its s