Wanting to test the response curves on some analog parts, [Don
Sauer] devised a way of using simple tools to graph analog tests
on a computer. Here you can see the results of testing NPN, PNP,
NMOS and PMOS transistors, but modifying the input circuitry
would let you test just about anything you want. [Don] is using
an Arduino as the hardware interface. He needed some additional
parts, like an op-amp and some passives. Instead of building
this on a breadboard, he printed the circuit out on a piece of
cardboard, hot glued the components in place, then wired them
up. This will let him reuse the interface in the future, but is
quicker than designing and etching a PCB. He uses a Processing
sketch to capture the test data streaming in from the Arduino.
Once recorded, he uses SciLab to create the graphs. He also
covers a method of sifting through the data using Octave,
another open source program that feels somewhat like MATLAB.