I turned a standard UNI-T UT33C+ digital multimeter into a wireless logging meter with a cheap Bluetooth module and a Python dashboard.
The fun bit: the meter already had an internal telemetry stream. I found it by accident while trying to shut up the continuity buzzer. This repo is the result: live readings on your PC, graphing, snapshots, and CSV logging without adding a microcontroller.
- Talks to a ZS-040 / HC-05 / HC-06 Bluetooth module wired straight to the meter's PCB.
- Finds and connects to the paired Bluetooth serial port automatically.
- Decodes live readings for voltage, resistance, continuity, diode mode, and temperature.
- Gives you a small transparent overlay window you can keep on top while you work.
- Lets you save labelled snapshots of readings.
- Logs readings to CSV for longer tests or debugging sessions.
- Wire a generic Bluetooth module to the meter's internal UART pad. You only need TX, VCC, and GND.
- Use the hardware wiring guide to find the pads.
- Use the Bluetooth setup guide to configure the module.
- Install the Python dependencies:
pip install pyserial matplotlib
- Start the dashboard:
python app.py
If you just want CSV logs without the GUI:
python ut33c_logger.py- Hardware wiring guide: where to solder, and what not to touch.
- Bluetooth setup guide: setting the ZS-040 module to 2400 baud so it can talk to the meter.
- Protocol reference: the 10-byte binary telemetry frame format.
- Reverse engineering notes: dead ends, UART fuzzing, timing attacks, and why the meter is read-only.
- Project architecture: the main Python files and a few conventions for working on the app.
The multimeter's internal ground is connected to the COM probe. Do not plug the meter into a grounded PC over USB while measuring high voltages.
Use Bluetooth. The isolation is the point.