LogiVOX — Eyes on the probes. Ears on the measurement.

When both hands are holding probes, looking away to read a multimeter can interrupt your work. LogiVOX gives your OWON XDM1041 a voice: press a foot pedal to hear the current reading, or enable AUTO to hear meaningful changes as measurements settle.

Built around a Raspberry Pi Zero 2 W, LogiVOX connects to the multimeter through USB—no modifications inside the instrument are required. A custom PCB and a 3D-printed enclosure bring the electronics together into a compact bench accessory.

HOW IT WORKS

• Foot pedal: press to hear the current measurement.

• TALK button: a short press reads the measurement when released.

• AUTO mode: hold TALK for two seconds to enable or disable automatic announcements, with spoken confirmation.

• Intelligent announcements: AUTO waits for stable readings and significant changes, rather than repeating the same value every few seconds.

• Status indicators: POWER, READY and VOICE LEDs show what the system is doing.

• Local speech: Italian prerecorded audio fragments provide spoken readings without a cloud TTS service during normal operation.

POWER AND SHUTDOWN

A battery-backed power circuit allows the Raspberry Pi to shut down cleanly when external power is removed. After shutdown, the hardware disconnects power from the Pi.

A separate FORCE OFF button provides an immediate hardware power cut. This is intended for forced shutdown when necessary; it does not perform an orderly operating-system shutdown.

HARDWARE AND ENCLOSURE

The build combines a Raspberry Pi Zero 2 W, a MAX98357A I²S audio amplifier, a speaker, a foot pedal and a custom power-management circuit.

The enclosure was designed specifically for the OWON XDM1041 and uses its existing rear mounting holes. Autodesk Fusion source files and a Bambu Studio project are available on GitHub.

Assembly includes small SMD components and a MAX98357A package with an exposed underside pad. Experience with fine-pitch SMD soldering, magnification and suitable reflow equipment is recommended.

PROJECT STATUS

The assembled prototype is working and has been tested on the bench with the OWON XDM1041.

The updated PCB incorporates the corrections validated on the prototype. KiCad checks report zero design-rule violations, zero unconnected items and zero schematic/PCB parity issues.

Only the OWON XDM1041 has been tested. Support for other instruments is not currently confirmed.

FILES AND SOFTWARE

Project repository:

https://github.com/SVeneziani/LogiVOX

The repository contains:

• KiCad schematic and PCB files.

• Raspberry Pi software for voice playback, pedal input, TALK/AUTO and UPS monitoring.

• Hardware-independent software tests.

• Enclosure design files.

• Operating notes, photographs and a demonstration video.

Gerber files, the schematic PDF and the component BOM are attached to this PCBWay project.

The installation guide and printing instructions are still being completed. Prerecorded voice WAV files are not included; the repository contains a macOS voice-generation helper. Audio redistribution terms remain to be clarified.

PURCHASED COMPONENTS

Links to the foot pedal, power module, pedal connector and panel-mount USB-C connector used in the prototype:

https://github.com/SVeneziani/LogiVOX/blob/main/docs/COMPONENTS.md

This purchase list complements the PCB BOM. Check the selected product variants and dimensions against the design before ordering.

USB COMMUNICATION AND WEB DASHBOARD

LogiVOX uses Jason Antman’s owon-xdm1041-server for communication with the multimeter, its web dashboard and measurement API. This is a separate software dependency:

https://github.com/jantman/owon-xdm1041-server

CREDITS

Design, assembly, enclosure and bench testing: Sergio Veneziani.

Software development and troubleshooting assistance: OpenAI ChatGPT/Codex, with additional debugging using Cursor.

Initial inspiration came from the PCBWay community project “Arduino-Based Speech Add-on for Modern Multimeters with SCPI Protocol”:

https://www.pcbway.com/project/shareproject/Arduino_Based_Speech_Add_on_for_Modern_Multimeters_with_SCPI_Protocol_95abefd4.html

LogiVOX grew from a practical bench idea into an exploration of electronics, software, PCB design and 3D printing. Shared here for fellow makers who enjoy building, learning and improving things.

LICENSING

The project design files shared on this page are licensed under the Creative Commons Attribution–NonCommercial–ShareAlike license selected above.

For commercial licensing enquiries, please contact Sergio Veneziani. Any commercial permission, royalties and obligations concerning modifications must be agreed separately in writing.

Software, third-party components and voice recordings are covered separately; see the GitHub repository for details.