Serial plotter in the browser
Beetwise plots live serial data in a browser tab.
The tool uses the Web Serial API, so no install and no driver are necessary.
Each value also appears as a register with editable bits.
The serial plotter step by step
Plot a value from a device:
- Connect the device to a USB port.
- Select Connect, then select the baud rate.
- Send one line for each sample, in the form Name:100,Name2:-300.
- End every line with a newline character.
- Select Plot to open the chart.
What each baud rate carries, at 8 data bits and 1 stop bit
| Baud | Bytes per second | Lines per second at 20 bytes |
|---|---|---|
| 9600 | 960 | 48 |
| 57600 | 5760 | 288 |
| 115200 | 11520 | 576 |
| 230400 | 23040 | 1152 |
| 460800 | 46080 | 2304 |
| 921600 | 92160 | 4608 |
Where the serial plotter is used
A serial plot shows a trend that a text log hides.
A sensor drift or an unstable supply is visible in a few seconds on a chart.
The data export gives a CSV file for a later analysis.
The serial plotter: points to note
- The Web Serial API needs a Chromium browser. Firefox and Safari do not support it.
- The page must use HTTPS, and the user must grant access to the port.
- Only one program can hold a serial port. Close any other serial monitor first.
- A line without a newline character stays in the buffer and does not appear.
- A rate above the link speed fills the buffer, and the chart then lags behind the device.
The full bit editor
The full editor holds many values, evaluates expressions across them, and reads live values from a serial port.
Open the full editorQuestions about the serial plotter
- Which browsers support this?
- Chrome, Edge and other Chromium browsers support the Web Serial API. Firefox and Safari do not.
- What data format does the tool expect?
- Comma separated name and value pairs, such as Name:100,Name2:-300. Each line ends with a newline.
- Can I export the data?
- Yes. The tool writes the samples to a CSV file for a spreadsheet or a script.
- How fast can I send samples?
- At 115200 baud a line of 20 bytes fits 576 times per second. Divide the baud rate by 10 for bytes per second.
- Why does the chart fall behind?
- The plot holds the last 100 points by default. Raise that limit, or send fewer samples per second.