Hackers have been building their own basic oscilloscopes out of inexpensive MCUs and cheap LCD screens for some years now, but microcontrollers have recently become fast enough to actually make such ‘scopes useful. [NJJ], for example, used a pair of Raspberry Pi Picos to build Picotronix, an extensible combined oscilloscope and logic analyzer.
This isn’t an open-source project, but it is quite well-documented, and the general design logic and workings of the device are freely available. The main board holds two Picos, one for data sampling and one to handle control, display, and external communication. The control unit is made out of stacked PCBs surrounded by a 3D-printed housing; the pinout diagrams printed on the back panel are a helpful touch. One interesting technique was to use a trimmed length of clear 3D printer filament as a light pipe for an indicator LED.
Even the protocol used to communicate between the Picos is documented; the datagrams are rather reminiscent of Ethernet frames, and can originate either from one of the Picos or from a host computer. This lets the control board operate as an automatic testing station reporting data over a wireless or USB-connected network. The display module is therefore optional hardware, and a variety of other boards (called picoPods) can be connected to the Picotronix control board. These include a faster ADC, adapters for various analog input spans, a differential analog input probe, a 12-bit logic state analyzer, and a DAC for signal generation.
If this project inspired you to make your own, we’ve also seen other Pico-based oscilloscopes before, including one that used a phone for the display.
