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feat: Remote e-stop over 4G — MQTT kill command → STM32 motor cutoff #60

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opened 2026-03-01 00:33:51 -05:00 by sl-jetson · 0 comments
sl-jetson commented 2026-03-01 00:33:51 -05:00
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Summary

Safety-critical remote emergency stop for outdoor autonomous operation. MQTT kill command received over cellular → immediate motor cutoff on STM32.

Requirements

  • MQTT topic: saltybot/estop — payload {"kill":true} triggers immediate motor disable
  • STM32 firmware: new CDC command ESTOP or binary flag in command protocol
  • Latency budget: <500ms from MQTT publish to motor cutoff
  • Failsafe: if cellular drops for >5s during autonomous outdoor mode, auto-stop
  • Re-arm requires physical button OR explicit MQTT {"kill":false} + RC arm sequence
  • LED: fast red blink during remote e-stop state
  • Telemetry: report e-stop source (local tilt / RC kill / remote MQTT)

Context

  • SIM7600X 4G HAT provides cellular (issue #58)
  • Existing safety: IWDG watchdog, tilt cutoff, RC CH5 kill (PR #4, #35)
  • This adds the remote kill layer for when operator is not in RC range
  • CRITICAL for outdoor autonomous ops — non-negotiable safety feature
## Summary Safety-critical remote emergency stop for outdoor autonomous operation. MQTT kill command received over cellular → immediate motor cutoff on STM32. ## Requirements - MQTT topic: `saltybot/estop` — payload `{"kill":true}` triggers immediate motor disable - STM32 firmware: new CDC command `ESTOP` or binary flag in command protocol - Latency budget: <500ms from MQTT publish to motor cutoff - Failsafe: if cellular drops for >5s during autonomous outdoor mode, auto-stop - Re-arm requires physical button OR explicit MQTT `{"kill":false}` + RC arm sequence - LED: fast red blink during remote e-stop state - Telemetry: report e-stop source (local tilt / RC kill / remote MQTT) ## Context - SIM7600X 4G HAT provides cellular (issue #58) - Existing safety: IWDG watchdog, tilt cutoff, RC CH5 kill (PR #4, #35) - This adds the remote kill layer for when operator is not in RC range - CRITICAL for outdoor autonomous ops — non-negotiable safety feature
sl-firmware was assigned by sl-jetson 2026-03-01 00:41:34 -05:00
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shaytac sl-controls sl-firmware sl-jetson sl-mechanical sl-perception sl-uwb sl-webui seb
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Reference: seb/saltylab-firmware#60
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