Pipetting with the electronic pipette

The electronic pipette is a wireless handheld pipette that an arm holds and operates. You connect to it once under a logical name, then drive it with the epipette_* calls from your robotic_code.py. These calls command real hardware: the piston moves, liquid is drawn in and pushed out, and tips are ejected.

Device names

You refer to a pipette by a logical name that you pass to init_epipette and then to every later call. These name constants are exported for you:

• EPIPETTE is "epipette", a plain default logical name.
• EPIPETTE_GREY is "epipette_grey", the logical name for the grey pipette.
• EPIPETTE_ML is "epipette_ml", the logical name for the millilitre pipette.

Two more constants hold the wireless device identifiers of the two pipettes wired to a cell, for passing as the ble_device_name argument to init_epipette:

• EPIPETTE_GREY_BLE_NAME: the device identifier of the grey pipette.
• EPIPETTE_ML_BLE_NAME: the device identifier of the millilitre pipette.

The logical name is your handle in code. The device identifier tells init_epipette which physical pipette to pair with. Pass the constant rather than a literal string, so your skill stays correct if the underlying device changes.

Connecting

init_epipette(name, ble_device_name="picus", debug=True)

Connect to a pipette and register it under a logical name. Call this once per device before any other epipette_* call.

• name (str): the logical name you will pass to every later call, for example EPIPETTE_GREY.
• ble_device_name (str, default "picus"): the wireless device to scan for and pair with. Pass one of the *_BLE_NAME constants to target a specific pipette.
• debug (bool, default True): turn on verbose connection logging.

This call blocks while it scans, pairs, and readies the device. It can block on the order of several minutes before timing out. It returns a handle to the connected device on success, or None if no matching pipette was found or the connection failed. If init_epipette was already called for this name, it returns the existing device without reconnecting.

from execution.execution_functions import *

if not is_sim_mode():
    init_epipette(EPIPETTE_GREY, ble_device_name=EPIPETTE_GREY_BLE_NAME)

Aspirate and dispense

epipette_aspirate(name, volume=5, speed=5)

Draw liquid into the tip.

• name (str): the logical name from init_epipette.
• volume (default 5): volume to aspirate. The source does not state a unit, so treat the unit as unspecified and match the values your device expects.
• speed (default 5): aspirate speed. Unit unspecified in source.

Returns {"success": True} when the aspirate completes. Returns {"success": False, "error": ...} if the pipette was never initialized under name or the pipette link is not available. If the wireless link drops mid-op it reconnects and retries a small number of times; if it still fails, or the error is not a dropped link, the call raises rather than returning.

epipette_dispense(name, volume=5, speed=5)

Push liquid out of the tip. Same arguments, units, return shape, and failure behaviour as epipette_aspirate.

• name (str): the logical name from init_epipette.
• volume (default 5): volume to dispense. Unit unspecified in source.
• speed (default 5): dispense speed. Unit unspecified in source.

if not is_sim_mode():
    epipette_aspirate(EPIPETTE_GREY, volume=50, speed=5)
    # move the arm over the destination well between these calls
    epipette_dispense(EPIPETTE_GREY, volume=50, speed=5)

Tips and clearing state

epipette_tip_eject(name)

Eject the tip currently on the pipette.

• name (str): the logical name from init_epipette.

Returns {"success": True} on completion, or {"success": False, "error": ...} if the pipette is not initialized under name or the link is unavailable.

epipette_home(name)

Return the piston to its zero position. Use this to clear a piston-drift error state that would otherwise cause the pipette to reject an aspirate or dispense. It is a good pre-run step to put the device in a known state.

• name (str): the logical name from init_epipette.

Returns {"success": True} on completion, or {"success": False, "error": ...} if the pipette is not initialized under name or the link is unavailable.

epipette_blow_out(name, speed=10)

Push out any residual liquid left in the tip and clear the device's "liquid present" state, so a following operation is not blocked by that warning.

• name (str): the logical name from init_epipette.
• speed (int, default 10): blow-out speed. Unit unspecified in source.

Returns {"success": True} on completion, or {"success": False, "error": ...} if the pipette is not initialized under name or the link is unavailable.

Recovering the link

epipette_reconnect(name)

Re-establish a wireless link to a pipette that was already connected with init_epipette but has since dropped. It reuses the known device, so it does not re-scan or re-pair, which makes it faster than a full init_epipette. On success it restores the pipette to its ready state.

• name (str): the logical name from init_epipette.

Returns {"success": True} when the link is back, or {"success": False, "error": ...} if the reconnect fails, the pipette was never initialized under name, or the link is unavailable. This call can block for up to about a minute.

epipette_disconnect(name)

Cleanly disconnect a pipette: it is taken out of its active state and the wireless link is closed.

• name (str): the logical name from init_epipette.

Returns {"success": True} once the disconnect completes, or {"success": False, "error": ...} if the pipette was not initialized under name or the link is unavailable. The logical name stays registered after disconnect, so a later epipette_reconnect(name) can bring the same device back.

Related