A Compact, Browser-Based ESP32 Oscilloscope
An oscilloscope is usually the most sensitive, and arguably most versatile, tool on a hacker’s workbench, often taking billions of samples per second to produce an accurate and informative representation of a signal. This vast processing power, however, often goes well beyond the needs of the signals in question, at which point it makes sense to use a less powerful and expensive device, such as [MatAtBread]’s ESP32 oscilloscope.
The oscilloscope doesn’t have a display; instead, it hosts a webpage that displays the signal trace and provides the interface. Since the software uses direct memory access to continually read a signal from the ADC, it’s easy to adjust the sampling rate up to the hardware’s limit of 83,333 Hz. In addition to sampling-rate adjustment options, the browser interface includes a crosshair pointer for easy voltage reading, an adjustable trigger level, attenuation controls, and the ability to set the test signal frequency. The oscilloscope’s hardware is simply a Seeed Studio Xiao development board mounted inside a 3D-printed case with an AA battery holder and three pin breakouts for ground, signal input, and the test signal output.
This isn’t the first ESP32-based oscilloscope we’ve seen, though it is the fastest. If you’re looking for a screen with your simple oscilloscope, we’ve seen them built with an STM32 and Arduino. To improve performance, you might add an anti-aliasing filter.