For hackers on a tight budget or with limited bench space, a USB oscilloscope can be a compelling alternative to a dedicated piece of hardware. For plenty of hobbyists, it’s a perfectly valid option. But while the larger discussion about the pros and cons of these devices is better left for another day, there’s one thing you’ll definitely miss when the interface for your scope is a piece of software: the feel of physical buttons and knobs.
But what if it doesn’t have to be that way? The ScopeKeypad by [Paul Withers] looks to recreate the feel of a nice bench oscilloscope when using a virtual interface. Is such a device actually necessary? No, of course not. Although one could argue that there’s a certain advantage to the feedback you get when spinning through the detents on a rotary encoder versus dragging a slider on the screen. Think of it like a button box for a flight simulator: sure you can fly the plane with just the keyboard and mouse, but you’re going to have a better time with a more elaborate interface.
The comparison with a flight simulator panel actually goes a bit deeper, since that’s essentially what the ScopeKeypad is. With an STM32 “Blue Pill” microcontroller doing its best impression of a USB Human Interface Device, the panel bangs out the prescribed virtual key presses when the appropriate encoder is spun or button pressed. The project is designed with PicoScope in mind, and even includes a handy key map file you can load right into the program, but it can certainly be used with other software packages. Should you feel so inclined, it could even double as a controller for your virtual spaceship in Kerbal Space Program.
Affordable USB oscilloscopes have come a long way over the years, and these days, using one is hardly the mark of shame it once was. But the look and feel of the classic bench scope is about as timeless as it gets, so we can certainly see the appeal of a project that tries to combine the best of both worlds.