Power Scope for $10
https://www.thebackshed.com/forum/forum_posts.asp?TID=11123&PN=1
Software is still a work in progress.
A minimal Oscilloscope design utilising a STM32F103 "Blue Pill" and a cheap mcuFriend 2.4" LCD, specifically to display the output voltage for an Inverter. Along with displaying th eAc waveform it will display RMS voltage, Current and Power.
LCD library is compatible with the 8bit mcuFriend 2.4" and 3.5" LCD.
PCD features:
PCB is compatible with the 8 bit mcuFriend "UNO" lcds as well as the SPI based LCDs.