“Create a cheap and basic but usable 500kS/s oscilloscope using the Scoppy Android app connected via Wi-Fi to your Raspberry Pi Pico W.
Introduction
In this guide will cover how to create a basic oscilloscope using a Raspberry Pi Pico W, an Android phone (or tablet), the Scoppy Android app and Scoppy Pico W firmware.
The devices communicate over Wi-Fi and so your precious phone (or tablet) never needs to be physically connected to the Pico W or the circuit under test. Whew!
Assuming you already have a Pico W and Android device the extra cost is approximately USD$2.
The scope will have a sample rate of 500kS/s, an input impedance of around 100k but is limited to signals with a voltage range of 0V to 3.3V. In later articles we will describe how to increase the input impedance and extend the range to include negative (and larger) voltages.
The scope will also do FFT, has an X-Y Mode and as a bonus you can also use your scope as a 24MHz logic analyzer.”