feat(hardware control): create logic to detect if tip has hit bottom … (

#15389)

…of well or liquid

Creates a new file called sensor_utils.py. Introduces new error type for
tip hitting bottom of the well when searching for liquid. Creates a
function that detects whether the tip has hit a liquid or the bottom of
the well based on pressure data.

fix EXEC-517

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hardware/opentrons_hardware/hardware_control/sensor_utils.py

@@ -0,0 +1,30 @@
+"""Functions aiding in Liquid Level Detection."""
+
+from opentrons_shared_data.errors.exceptions import (
+    TipHitWellBottomError,
+    LiquidNotFoundError,
+)
+
+
+import numpy as np
+
+
+def did_tip_hit_liquid(
+    pressure_readings: list[float], liquid_solid_threshold: float
+) -> bool:
+    """Detects if tip has hit liquid or solid based on given pressure data."""
+    if len(pressure_readings) < 5:
+        raise LiquidNotFoundError(
+            "Liquid not found. Not enough data to calculate pressure change",
+        )
+    pressure_difference = np.gradient(pressure_readings[-5:], 1)
+    end_difference = pressure_difference[-1]
+    if end_difference > liquid_solid_threshold:
+        # Hit Bottom of Well
+        raise TipHitWellBottomError(
+            "Tip hit the bottom of the well.",
+            {"Pressure change detected: ": str(end_difference)},
+        )
+    else:
+        # Hit Liquid
+        return True

shared-data/errors/definitions/1/errors.json

@@ -126,6 +126,10 @@
       "detail": "Liquid Not Found",
       "category": "roboticsControlError"
     },
+    "2018": {
+      "detail": "Tip Hit Well Bottom",
+      "category": "roboticsControlError"
+    },
     "3000": {
       "detail": "A robotics interaction error occurred.",
       "category": "roboticsInteractionError"

shared-data/python/opentrons_shared_data/errors/codes.py

@@ -61,6 +61,7 @@ class ErrorCodes(Enum):
     FAILED_GRIPPER_PICKUP_ERROR = _code_from_dict_entry("2015")
     MOTOR_DRIVER_ERROR = _code_from_dict_entry("2016")
     LIQUID_NOT_FOUND = _code_from_dict_entry("2017")
+    TIP_HIT_WELL_BOTTOM = _code_from_dict_entry("2018")
     ROBOTICS_INTERACTION_ERROR = _code_from_dict_entry("3000")
     LABWARE_DROPPED = _code_from_dict_entry("3001")
     LABWARE_NOT_PICKED_UP = _code_from_dict_entry("3002")

shared-data/python/opentrons_shared_data/errors/exceptions.py

@@ -629,6 +629,24 @@ def __init__(
         )
 
 
+class TipHitWellBottomError(RoboticsControlError):
+    """Error raised if tip hits bottom of well while trying to detect liquid level."""
+
+    def __init__(
+        self,
+        message: Optional[str] = None,
+        detail: Optional[Dict[str, str]] = None,
+        wrapping: Optional[Sequence[EnumeratedError]] = None,
+    ) -> None:
+        """Initialize TipHitWellBottomError."""
+        super().__init__(
+            ErrorCodes.TIP_HIT_WELL_BOTTOM,
+            message,
+            detail,
+            wrapping,
+        )
+
+
 class LabwareDroppedError(RoboticsInteractionError):
     """An error indicating that the gripper dropped labware it was holding."""