Lego Port

The LegoPort class is only needed when manually reconfiguring input/output ports. This is necessary on the BrickPi but not other platforms, such as the EV3. Most users can ignore this page.

class ev3dev2.port.LegoPort(address=None, name_pattern='*', name_exact=False, **kwargs)

The lego-port class provides an interface for working with input and output ports that are compatible with LEGO MINDSTORMS RCX/NXT/EV3, LEGO WeDo and LEGO Power Functions sensors and motors. Supported devices include the LEGO MINDSTORMS EV3 Intelligent Brick, the LEGO WeDo USB hub and various sensor multiplexers from 3rd party manufacturers.

See the following example for using this class to configure sensors:

Some types of ports may have multiple modes of operation. For example, the input ports on the EV3 brick can communicate with sensors using UART, I2C or analog validate signals - but not all at the same time. Therefore there are multiple modes available to connect to the different types of sensors.

In most cases, ports are able to automatically detect what type of sensor or motor is connected. In some cases though, this must be manually specified using the mode and set_device attributes. The mode attribute affects how the port communicates with the connected device. For example the input ports on the EV3 brick can communicate using UART, I2C or analog voltages, but not all at the same time, so the mode must be set to the one that is appropriate for the connected sensor. The set_device attribute is used to specify the exact type of sensor that is connected. Note: the mode must be correctly set before setting the sensor type.

Ports can be found at /sys/class/lego-port/port<N> where <N> is incremented each time a new port is registered. Note: The number is not related to the actual port at all - use the address attribute to find a specific port.


Returns the name of the port. See individual driver documentation for the name that will be returned.


Returns the name of the driver that loaded this device. You can find the complete list of drivers in the [list of port drivers].


Returns a list of the available modes of the port.


Reading returns the currently selected mode. Writing sets the mode. Generally speaking when the mode changes any sensor or motor devices associated with the port will be removed new ones loaded, however this this will depend on the individual driver implementing this class.


For modes that support it, writing the name of a driver will cause a new device to be registered for that driver and attached to this port. For example, since NXT/Analog sensors cannot be auto-detected, you must use this attribute to load the correct driver. Returns -EOPNOTSUPP if setting a device is not supported.


In most cases, reading status will return the same value as mode. In cases where there is an auto mode additional values may be returned, such as no-device or error. See individual port driver documentation for the full list of possible values.