Use An Analog Oscilloscope To Display Digital Logic

[Mike Bradley] wanted to use his oscilloscope to display 8 channels of digital signals. Alas, the analog unit didn’t have this capability. Not to worry, he threw together an adapter module that does the trick. Using a PIC 18F26K20 microcontroller he inputs four or eight channel digital logic (at 5V) and filters the output to an analog signal that the oscilloscope can interpret. What you see in the photo above is the result.