Release Notes
Heel2Toe™ Device
Firmware rev 12 · latest patch v12.0.2
What changed in the Heel2Toe firmware — longer sessions, gentler SD-card writes, automatic foot detection, direct phone access, and a heel-strike beep that no longer quits mid-session.
Version 12.0.2 Newest
Longer sessions, reliable long recordings on the SD card, and tighter behavior when something is wrong with the SD at session start.
Sessions can now be up to 6 hours
Maximum session length raised from 60 minutes to 360 minutes to match the device’s battery life. Bench-tested end-to-end at a full 360-minute / 2.16-million-sample session with zero data loss. Values above 360 are now clamped to 360 (with a log warning) instead of silently collapsing to a 3-minute session.
Smoother, longer-lasting SD-card writes
The device now buffers about half a second of motion samples and writes them in one go — roughly 50× fewer flash erase cycles per session, for meaningfully longer SD-card life. At 100 Hz on a class-10 card it’s invisible to the operator: same data, same timing, gentler on the card.
Clearer error signaling at session start
If the SD card can’t be opened when you press start (full, damaged, missing, or wrongly formatted), the device now gives the same clear signal used everywhere else for SD failures: a persistent red LED plus 5 short beeps. No more “session started but nothing is being saved” mystery.
Impact. Sessions of 60 minutes or less behave exactly as before. Settings that asked for >60 minutes now actually run that long (up to 360). Damaged or absent SD cards give one consistent, unambiguous error signal.
Version 12.0.1
Prepares the rev12 line for deployment with an updated firmware version identifier, plus a targeted fix.
Manual threshold fix — in manual mode, configured heel-strike thresholds are now applied consistently during session processing (validated at −50, −100, −250, −350).
Version tracking — firmware identifier updated for deployment clarity and support traceability.
The big rev 12 release
Fixed: the heel-strike beep no longer stops mid-session
Previously the audible beep could go quiet partway through a session with no way to recover without restarting. We traced it to the auto-threshold algorithm drifting to an extreme it couldn’t return from. It now uses a stable update rule that holds the ~90% good-step target over arbitrarily long sessions — the beep works from the first step to the last.
New features
Automatic left / right foot detection — a small on-device neural network identifies the foot from the first few steps. No manual setting.
iPhone & Android support — plug Heel2Toe straight into a phone over USB and open the SD card in the Files app. The device shows up as HEEL2TOE — no PC required.
SD-card write protection — if the card is full, damaged, or wrongly formatted, the device catches it early (red LED + five beeps) and stops writing, so data isn’t silently corrupted.
Improvements you’ll notice
Smarter beep tuning — the auto-threshold adapts more aggressively when too many steps in a row score “good,” holding a ~90% good-step target as your gait improves.
Faster, more reliable USB — USB-C recognized on first plug, iPhone Files mounts reliably on the first try, and the device now identifies itself as PhysioBiometrics — Heel2Toe Sensor.
Built-in diagnostics — every plug-in writes version.txt (firmware, build date, hardware revision) and time.txt (device clock) to the card, so you can confirm the device is healthy and time-synced.
Bug fixes
USB descriptor order corrected for USB-C compatibility.
Time-set command length validation fixed.
Heel2Toe firmware rev 12 ships preinstalled on every device shipped on or after May 1, 2026.
