====== Elevator project ======

A simple, 2-levels elevator based off an inexpensive commercial workshop winch.


===== Requirements =====

  * Allows to travel between 2 levels approximately 2.7m apart vertically
  * Approx. 110x70cm platform
  * Platform is flush with the floor at ground level and upper level
  * Upper level is secured with a gate that automatically locks when not being at the top
  * Gate safety may be disengaged using a key
  * Anti-pinch up-going safety mechanism
  * Anti-crush down-going mechanism
  * Call/send/stop controls on both levels and on platform (may be disconnected on platform to convert it back to a utility lift for public compliance)
  * E-stops on both levels
  * On/Off controls on both levels
  * Ground level controls above 1.2m high
  * Global key-based On/Off control at ground level


===== Workflows =====

==== When going up is requested ====

  * Go up
  * Stop if anti-pinch up-going safety is triggered
  * Stop if going down is requested
  * Stop if stop is requested
  * Stop when reaching the top level
  * Unlock gate when reaching the top level


==== When going down is requested ====

  * Try to lock gate if not disengaged and unlocked
    * Signal if unsuccessful
  * Go down
  * Stop if anti-crush down-going safety is triggered
  * Stop if going up is requested
  * Stop if stop is requested
  * Stop when reaching the ground level


==== When gate safety is engaged ====

  * Try to lock gate if not at top level


==== When gate safety is disengaged ====

  * Unlock gate