11.2. Instructions

The circuit for this project couldn't be much simpler. It's essentially just an Arduino with probes connected to a number of analog and/or digital inputs with all the hard work done in the software, plus a "power" LED to show when it's alive.

In our prototype, we fitted a total of eight input probes but because the Duemilanove and most other Arduino designs only have six analog inputs, we connected the first six probes to the analog inputs and the remaining two to digital inputs. This allows up to six analog waveforms to be sampled, which is plenty for most applications, but still allows up to eight digital lines to be analyzed in case we need to process an 8-bit parallel data bus.