A few posts ago I offered some general ideas on adding a tachometer to TouchDRO setup that covered some theory and a basic example circuit. Since then I've received a ton of emails asking for more details, so in the next few posts I will provide a detailed start-to-finish example of building a tachometer for my Jet 1024 Lathe. In the post "DIY Tachometer for Your Mill or Lathe" I covered the basic of tachometer operation and provided a basic tachometer circuit using a IR emitter/receiver couple. A number of people wanted to use a Hall effect sensor with a magnetic encoder disk, so I will go that route for this design. Along the way I will use this project as mini-tutorial for some of the basic TouchDRO functionality.