Support

Found a bug or have a question? Open an issue on GitHub. Please include your device, its OS version and the meter's firmware version (shown at power-on).

The app doesn't find my meter

• Turn on the meter's Bluetooth: hold 1ms PEAK until BT shows on the display. Holding it again turns Bluetooth off.
• Allow Readout to use Bluetooth: iPhone and iPad Settings > Readout; Mac System Settings > Privacy & Security > Bluetooth.
• Only one app can be connected to the meter at a time. Close the official EEVblog app or any other app that might be connected.
• Older meters may advertise as "Bluegiga" rather than "121GW". Readout finds both.

How do I measure AC, temperature, capacitance…?

The dial picks the group, and MODE cycles within it, exactly as on the meter. For example, V gives DC, AC and DC+AC; mV gives DC, AC and temperature; Ω gives resistance, continuity, diode and capacitance. The app can press MODE for you but can't turn the dial. The 121GW manual has the full list.

Long presses

Hold a button in the app for about a second for a long press. The small labels under the buttons are what holding does: 1 kHz low-pass filter (REL, in AC) and Bluetooth (1ms PEAK).

Getting my readings out

Save the recording as a session, open it in the Sessions tab and tap Export CSV. Times are in UTC and values in SI base units (V, A, Ω, Hz, F, °C).

Using it with an AI assistant

On the Mac, Settings > AI assistants turns on a local MCP server. Setup for Claude Code, Claude Desktop, VS Code and Cursor.