Serial Port DataStreamer Plugin

Streams data from a serial port into PlotJuggler. Useful for microcontrollers, embedded devices, and any hardware that sends structured data over UART/USB-serial.

Dependencies

This plugin requires Qt5SerialPort. It is optional — if the library is not found at build time, the plugin is skipped and the rest of PlotJuggler builds normally.

Ubuntu / Debian

sudo apt install libqt5serialport5-dev

Fedora

sudo dnf install qt5-qtserialport-devel

Supported Protocols

Currently only JSON is supported. The device must send newline-separated or back-to-back JSON objects, e.g.:

{"temperature":23.5,"pressure":1013.2}
{"temperature":23.6,"pressure":1013.1}

Nested objects are handled correctly:

{"sensor":{"temp":23.5,"hum":60},"ts":1234}

Arbitrary bytes between JSON objects (e.g. debug prints, blank lines) are ignored — the splitter looks for matching { ... } pairs.

Usage

1. Open PlotJuggler
2. Go to Streaming and select Serial Port
3. Configure:
   • Port — select from detected serial devices (click Refresh to rescan)
   • Baud rate — must match your device (common: 115200, 9600)
   • Data bits / Parity / Stop bits / Flow control — match your device settings
   • Protocol — select JSON and configure the message parser
4. Click OK to start streaming

Settings are remembered between sessions.

Notes

• Parse errors are non-blocking. If a message fails to parse, the plugin increments a failure counter shown in the notification bar rather than stopping the stream. Click the notification to see the count and reset it.
• Port selection is robust. The plugin identifies ports by system path, not by the display string, so devices with unusual manufacturer names won't cause issues.
• Buffer safety. The JSON splitter caps its internal buffer at 1 MB to prevent runaway memory usage from malformed data. If exceeded, the buffer is reset and the splitter resynchronizes on the next {.