If you’ve got an ARM development board gathering dust in the
corner of your shop, perhaps you could repurpose it as an
oscilloscope. [Arend-Paul Spijkerman] was able to use an mbed
and LPCXpresso as the hardware end of an oscilloscope. He didn’t
use a standalone screen as a display, instead opting to push the
scope readings from the hardware to a computer for display. This
was greatly simplified by using StampDock as a basis for the
GUI. His circuit diagrams calls for an RS-232 connection for the
LPCXpresso but not for the mbed. We’re not quite familiar enough
with the mbed to know why, but perhaps those in the know can
clue us in by leaving a comment. The probe connections are quite
simple, each made up of a voltage divider and a pair of diodes.
But the breadboard above looks much busier because it has two
oscilloscope circuits built on it, and there’s a 10 MHz clock
and a 4040 ripple counter which were used to provide a test
signal.