It's sometimes said that to a maker with a hammer, everything looks like a nail - and to a maker with an Arduino, everything looks like a microcontroller project. It's this thought process that leads many makers to build their own tools using Arduinos and compatibles, from custom-built devices like the Arachnid Labs Tsunami and an open-hardware solder paste dispenser to upgrading and repurposing off-the-shelf devices like the classic toaster oven reflow station.
Now there's a new entry to add to the list: an Arduino-controlled table saw. Using an Arduino Pro Instructables user Rocket Scientist was able to upgrade his second-hand table saw to include a digital fence indicator with a 0.001" accuracy, displayed on the popular recycled Nokia 5110 liquid-crystal display panel. "Realistically I'll never expect myself to be so precise in my cuts," he admits, "but aiming for extra accuracy will never hurt."
There are two clever aspects to the build, which otherwise uses entirely standard components: a linear potentiometer strip, which performs the actual measurements and operates in a line rather than the rotation of a normal potentiometer, and oversampling - required to get the measurement resolution desired from the Arduino Pro's 10-bit analogue to digital converter (ADC). Using oversampling, it's possible to have the 10-bit ADC act like a 16-bit ADC - providing a finer resolution to its readings and, if the oversampling is done correctly, without adversely affecting accuracy.
For anyone interested in upgrading bench tools, boosting sensor resolution with oversampling, or simply in using a linear potentiometer, the full instructions are a worthwhile read, with Rocket Scientist promising to update the project in the future as he increases its capabilities.
A few months ago I discovered the YouTube woodworking community and the likes of Darbin Orvar and Bob Clagett. I've learned a great deal from watching their videos and I really appreciate their blend of woodworking and electronics. When I got my first 'new-to-me' table saw, I thought about how cool a digital readout would be. Of course I found a commercial product on Amazon. But you never learn anything buying an off the shelf solution so I decided to build my own interpretation.