[Privatier] wrote in to let us know about lxardoscope, his project that lets you use an Arduino as hardware input for a Linux-based oscilloscope display. This implementation offers two channels with about 3000 samples per second from each. He touts some of the GUI options like vertical resolution between 2mV and 10V per division. That part kind of stumps us because we don’t see how a measurement of 10V (or more) can be taken using the schematic included. But you’re comprehension may surpass ours so do take a look yourself.
He is using an Arduino Uno for his testing. But to get around some issues he’s experienced with other USB-based solutions he implemented a serial port connection instead. You’ll need to remove the ATmega chip from the Arduino board after flashing the code to it, and then build a circuit around it which includes a power source where -2.5V is ground and 2.5V is VCC. All in all, you’ll need a 16 Mhz crystal, HEF4069 hex inverter, ATmega8-family microcontroller, and a few passive components to build this on a breadboard.