HexCurrent

Standalone EEPROM-side app source for the Team RobotMad HexCurrent hexpansion.

HexCurrent is intended for badge hexpansion developers who need to measure real-world current draw from a Hexpansion Under Test. The board sits between the badge and the device under test, passes through the normal hexpansion signals, and exposes an INA226 so the companion app can show live current and voltage and record time-series capture data.

What This Repo Contains

• hexcurrent.py: the MicroPython app that is compiled to .mpy, copied onto a hexpansion EEPROM, and run by BadgeOS as app.mpy.

The exported runtime class is HexCurrentApp.

Usage Modes

HexCurrent supports two deployment models:

• Installed on the HexCurrent EEPROM itself, in which case the app runs directly from that port.
• Installed permanently on the badge, in which case it scans all hexpansion slots and uses the first port that exposes an INA226.

If the Hexpansion Under Test includes its own EEPROM, the badge-installed mode must be used so the HexCurrent EEPROM is not present on the shared I2C bus.

Current Scope

The current implementation provides:

• Live monitor mode showing current and voltage from the INA226.
• Timed capture mode with a persisted timeout setting.
• Manual stop of an in-progress capture using the confirm button.
• Post-capture charting of current and voltage over time.
• CSV export of recorded samples.
• Optional save-to-hexpansion-filesystem support when the app is running from the HexCurrent EEPROM.

Building

Compile the EEPROM app with mpy-cross:

mpy-cross -v hexcurrent.py -o hexcurrent.mpy

The resulting hexcurrent.mpy should then be copied into the consuming app's EEPROM/ directory. When a host app writes that file to a hexpansion EEPROM it is renamed to app.mpy on the EEPROM so BadgeOS will discover it automatically.

Hardware Notes

• HexCurrent uses VID 0xCBCB, PID 0x5000.
• The onboard INA226 reports bus voltage in millivolts and current in milliamps.
• An optional flying lead can be used to probe a voltage point on the device under test while the app continues to log current and voltage samples.

Easy Insatalltion

This EEPROM image is included in HexManager, which can vendor this repository as a git submodule and compile hexcurrent.py into EEPROM/hexcurrent.mpy for EEPROM programming.