PPMScope was developed as an accessible do-it-yourself oscilloscope with an Open Source design. PPMScope is designed so that it can be constructed by an electronics hobbyist using the included instructions. The design is a compromise between features and cost. The bandwidth is lower than a commercial scope, so it's use is limited to signals of 500 kHz and below. It's sample buffer is also smaller than a commercial scope but is sufficient for most oscilloscope functions. This is a version based on the PIC16F877A microcontroller running with a 20MHz clock. The maximum sampling rate is 1 MHz with a 5 Mhz equivalent sampling.