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FlexSEA-Rigid is a one-board solution that integrates the features of four individual boards. It is used for Dephy ExoBoots, and for the Dephy Actuator Packages. The design is divided in four logical blocks. Staying consistent with the business-naming convention adopted previously, the modules are named Manage, Execute, Regulate, and Communicate.

Manage (Mn): very similar to the original FlexSEA-Manage, this module is centered around a powerful STM32F4 (STM32F7 for v1.0 and above) Cortex-M4 microcontroller. It will host our high-level walking controllers.

Execute (Ex): simplified version of the original FlexSEA-Execute, this module has one and only one goal: control our brushless motor. It will run fast, low-level controllers, based on the state requested by Manage.

Regulate (Re): this module is a hybrid between FlexSEA-Battery and the Safety-Co Processor microcontroller that was present on the original FlexSEA-Execute circuit. It contains the turn-on/off logic, and many sensors to monitor experiments and board state. It supervises Manage and Execute.

Communicate (Co): this module regroups all of the communication peripherals present on FlexSEA-Rigid. Wired interfaces include one USB port (CDC, virtual COM port), and one RS-485 interface. Wireless capability is provided by a pre-certified Bluetooth module (RN-42 or equivalent). Other peripherals are available on the expansion connector.

PCB Versions


  • First integration of the discrete FlexSEA boards into a unified system.
  • Released in February 2017
  • Used for some Dephy Exoskeletons
  • Used only for some ActPack prototypes. Only one client has that version.


  • Released in November 2017
  • Used for some Dephy Exoskeletons
  • Used for all ActPack sold before 2019 (see exception above)
  • Main changes vs 0.1:
    • Removed unused USB ports for Re and Ex
    • Smaller programming connectors (0.5mm) for Re and Ex
    • Mirrored J4 for easier access to the lock
    • Pico-Clasp connectors replace the previously used PicoBlade connectors
    • 10A fuse (was 30A)
    • 20A current sensor (was 30A)
    • Much cleaner PCB layout
    • Improved hardware protections, extra TVS (Transient Voltage Suppressors) on power buses
    • Other minor improvements: extra pull-downs, extra signals between µC, etc.


  • Released in November 2018
  • Used for all ActPack sold in 2019
  • Very similar to 0.2, but we had to re-order for the OSL project so we rolled in some simple but important improvements:
    • Self-turn-on patch to eliminate sparks when connecting a battery of more than 30V
    • Much lower surge current at turn-on to eliminate random blown fuses
  • Integrated better sourced components to work around part shortages

1.0 - 3.0:

  • November 2017 - May 2019
  • Exclusively used for Dephy Exoskeletons, not sold as stand-alone boards or as ActPacks
  • Different microcontroller, sensors, form-factor, radios, etc.


rigid.txt · Last modified: 2020/07/09 21:07 (external edit)