ALFsr Tutorial

NAOqi Sensors - Overview | API | Tutorial


Using the values in ALMemory

This Python example shows how to retrieve the values in ALMemory. It gives the values of the total weight on both feet until foot contact is lost.

sensors_fsr.py


# -*- encoding: UTF-8 -*-
from naoqi import ALProxy
import time
import sys

def main(robotIP):
    PORT = 9559

    # Create proxy to ALMemory
    try:
        memoryProxy = ALProxy("ALMemory", robotIP, PORT)
    except Exception, e:
        print "Could not create proxy to ALMemory"
        print "Error was: ", e

    footContact = True

    footContact = memoryProxy.getData("footContact")

    while footContact:
        footContact = memoryProxy.getData("footContact")
        leftFoot    = memoryProxy.getData("leftFootTotalWeight")
        rightFoot   = memoryProxy.getData("rightFootTotalWeight")
        print ("Total weight on left foot: %.2f kg, on right foot: %.2f kg" % (leftFoot, rightFoot))
        time.sleep(1.0)

    print("Foot contact lost")


if __name__ == "__main__":
    robotIp = "127.0.0.1"

    if len(sys.argv) <= 1:
        print "Usage python sensors_fsr.py robotIP (optional default: 127.0.0.1)"
    else:
        robotIp = sys.argv[1]

    main(robotIp)

Another possible application is to implement a module with a callback on the event “footContactChanged” (see Event subscription for information on how to do so).

Direct access

It is also possible to access sensors values directly, such as in the following example: sensors_getFsrValues.py.


# -*- encoding: UTF-8 -*-
from naoqi import ALProxy
import sys


def main(robotIP):
    PORT = 9559

    # Create proxy to ALMemory
    try:
        memoryProxy = ALProxy("ALMemory", robotIP, PORT)
    except Exception, e:
        print "Could not create proxy to ALMemory"
        print "Error was: ", e

    # Get The Left Foot Force Sensor Values
    LFsrFL = memoryProxy.getData("Device/SubDeviceList/LFoot/FSR/FrontLeft/Sensor/Value")
    LFsrFR = memoryProxy.getData("Device/SubDeviceList/LFoot/FSR/FrontRight/Sensor/Value")
    LFsrBL = memoryProxy.getData("Device/SubDeviceList/LFoot/FSR/RearLeft/Sensor/Value")
    LFsrBR = memoryProxy.getData("Device/SubDeviceList/LFoot/FSR/RearRight/Sensor/Value")

    print( "Left FSR [Kg] : %.2f %.2f %.2f %.2f" %  (LFsrFL, LFsrFR, LFsrBL, LFsrBR) )

    # Get The Right Foot Force Sensor Values
    RFsrFL = memoryProxy.getData("Device/SubDeviceList/RFoot/FSR/FrontLeft/Sensor/Value")
    RFsrFR = memoryProxy.getData("Device/SubDeviceList/RFoot/FSR/FrontRight/Sensor/Value")
    RFsrBL = memoryProxy.getData("Device/SubDeviceList/RFoot/FSR/RearLeft/Sensor/Value")
    RFsrBR = memoryProxy.getData("Device/SubDeviceList/RFoot/FSR/RearRight/Sensor/Value")

    print( "Right FSR [Kg] : %.2f %.2f %.2f %.2f" %  (RFsrFL, RFsrFR, RFsrBL, RFsrBR) )


if __name__ == "__main__":
    robotIp = "127.0.0.1"

    if len(sys.argv) <= 1:
        print "Usage python sensors_getFsrValues.py robotIP (optional default: 127.0.0.1)"
    else:
        robotIp = sys.argv[1]

    main(robotIp)