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„Libraries“ for Pybricks

Lok24
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Lok24

Lok24

Posted
Posted (edited)

Hi all,

when starting with python and the program “motor control” I started to consider a kind of structure to be reused in other projects and all be parametrized easily.
And so decided to use following structure:

  •         Parameters
  •         Function
  •         Routines and classes
  •         Main

As an example, a simple program to start and stop all kind of motors on all ports of a city hub (without any code of classes)

  

v = 30
dirMotorA = 1       # Direction 1 or -1
dirMotorB = -1       # Direction 1 or -1
START = "B+"
STOP = "B0"

function:  
    if CheckButton(START): 
        drive(v)
      
    if CheckButton(STOP): 
        drive(0)
        wait (100)    

# -----------------------------------------------
#  classes and routines
# -----------------------------------------------         

def CheckButton(x):
class delay:
def drive():
def portcheck(i):    
class device():
class (remote):

# Ininitialize
motor = [0,0,0]
motor[1] = device(Port.A,dirMotorA)
motor[2] = device(Port.B,dirMotorB)

portcheck(1)
portcheck(2)    

# -----------------------------------------------
# Main
# -----------------------------------------------

while True:
    remote()
    function()
    wait(10)

 

As you can see all parameter are at the beginning, "function" is the actual “user program”.
All other is something that would normally be located in libraries, but as far as I know it is not possible in Pybricks – or am I wrong?

Where is the benefit?

There are routines to detect motors, determine their types, handle .dc and .run depending on what is connected, reconnect the remote, timers and so on, which could be the easily reused by others .
Would it be reasonable to expand the idea and write such classes to be shared by many users?
And even users who have no experience in python they should be able to change the parameters according to their needs.

Edited by Lok24
vascolp

vascolp

Posted
Posted
1 hour ago, Lok24 said:

Hi all,

when starting with python and the program “motor control” I started to consider a kind of structure to be reused in other projects and all be parametrized easily.

All that is possible.

Just not that simple, specially if you are talking to the Remote and have to associate actions to the buttons.

In Remote Bla Bla, if you skip the configuration mode, the play mode does all that, it reads a configuration, currently from the Remote but could perfectly be form some initial configuration lines... and it could be simpler and more powerful.

While it could prove to be useful to bring people to use PoweredUp, their is stilI a number of people who wouldn't go that way (I guess you already knew I would think that :classic:).

But it is an interesting idea anyway. In fact, PyBricks has the DriveBase class which is sort of similar but for robotics, and it requires a bit more of programming.

Lok24

Lok24

Posted
  • Author
Posted (edited)
1 hour ago, vascolp said:

Just not that simple, specially if you are talking to the Remote and have to associate actions to the buttons.

this ist what the programmer/user needs: 

UP = "A+"
DOWN = "A-"
STOP = "A0"
SWITCH = "CENTER"

or i.e. 

FOR = "B+"
BACK = "A-"
STOP = "B0"

and here is the routine "CheckButton" 

def CheckButton(x):
    try:
        button = remote.buttons.pressed()
        if x == "A+"  : x = Button.LEFT_PLUS
        if x == "A-" : x = Button.LEFT_MINUS
        if x == "A0"  : x = Button.LEFT

        if x == "B+"  : x = Button.RIGHT_PLUS
        if x == "B-" : x = Button.RIGHT_MINUS
        if x == "B0"  : x = Button.RIGHT
    
        if x == "CENTER"  : x = Button.CENTER
        
        if x in button:
            return True
        else:
            return False
    except:
        return()

So the buttons have user-friendly predefined names, and no remote connected does not lead to an error.

and the remote itself: 

# --check if remote is connected ---------------------------------
    
    try:
        button = remote.buttons.pressed()
        hub.light.on(LEDconn)
        remoteConnected = True
    except OSError as ex:
        hub.light.on(LEDnotconn)
        print("Remote not connected")
        remoteConnected = False
       
        if watchdog == True:
            v=0
            drive()
        try:
            # reconnect remote
            remote = Remote(timeout=1000)
            wait(100)
            print("Remote reconnected")
            remoteConnected = True
        except OSError as ex:
            print("Remote not connected")

So it's very simple to use this in "function" in every program.
As you see "function" does not contain any "remote".....

I use this i.e for a program, that runs a motor with a certain sped (like an adjustable battery box).
But you can at any time connect a remote to adjust.

My question is: is it a good idea, and would some people (who have much better python knowledge than I have)  be interested to create a pool of such classes?

Here is the complete program "MotorControl": 

# -----------------------------------------------
# MotorControl
#
# uses https://code.pybricks.com/ , LEGO City hub, LEGO remote control
# connect 1 or 2 motors of any kind to Port A and/or B
#
# Version 2_9
# -----------------------------------------------/
from pybricks.parameters import * # Color

# -----------------------------------------------
#  Set user defined values
# -----------------------------------------------

# define the two profiles
# profil_x = (minimun speed,maximum Speed,accelerate in steps of ..., wait for next acceleration(in ms)

Profil_A = (20,100,10,100)  #min,max,step,acc
Profil_B = (10,500,5,200)   #min,max,step,acc

# define direction of motors

dirMotorA = 1       # Direction 1 or -1
dirMotorB = -1       # Direction 1 or -1

autoacc = False      # accelarate continously when holding butten 

# -----------------------------------------------
#  Set general values
# -----------------------------------------------

# assign buttons to function1 
# syntax: function = "name"
# name may  be "A+","A-","A0","B+","B-","B0","CENTER"

UP = "A+"
DOWN = "A-"
STOP = "A0"
SWITCH = "CENTER"

mode=1              # start with function number...
watchdog = False    # "True" or "False": Stop motors when loosing remote connection
remoteTimeout =10   # hub waits x seconds for remote connect after starting hub
remoteName = ""     # connect this remote only

# Color and brightness of Hub LEDs
LEDconn = Color.GREEN*0.3       # if Hub connected, color * brightness
LEDnotconn = Color.RED*0.5      # if Hub is not connect, color * brightness

LED_A = Color.GREEN*0.3       # Remote Profil_A, color * brightness
LED_B = Color.RED*0.5      # Remote Profil_B, color * brightness

# -----------------------------------------------
#  Import classes and functions
# -----------------------------------------------

from pybricks.pupdevices import DCMotor, Motor, Remote
from pybricks.parameters import Port, Stop, Button, Color
from pybricks.hubs import CityHub
from pybricks.tools import wait, StopWatch
from pybricks.iodevices import PUPDevice
from uerrno import ENODEV

# -----------------------------------------------
#  function 1 / drive motors
# -----------------------------------------------

def function1():

    vmax = profile[mode].vmax
    vmin = profile[mode].vmin
    accdelay =  profile[mode].acc
    step = profile[mode].step
  
    global v
   
    if CheckButton(UP) and not CheckButton(STOP) : 
        for x in range (1, step + 1):
            v = v + 1
            if v > vmax :
                v = vmax
            if v > 0 and v < vmin:    
                v = vmin
            if abs(v) < vmin:
                v = 0
            drive()
            wait (accdelay)  
            if v==0: 
                break 
        # further acceleration if button keeps pressed
        while autoacc == False and CheckButton(UP) :    
            wait (100)
        # avoid changing direction when reaching "0"     
        while v == 0 and  CheckButton(UP):  
            wait (100)

    if CheckButton(DOWN) and not CheckButton(STOP):
        for x in range (1, step + 1):
            v = v-1
            if v < vmax*-1 :
                v = vmax*-1
            if v < 0 and v > vmin*-1:    
                v = vmin*-1
            if abs(v) < vmin :
                v = 0   
            drive()
            wait (accdelay)  
            if v==0: 
                break 
        # further acceleration if button keeps pressed
        while autoacc == False and CheckButton(DOWN) :    
            wait (100)
        # avoid changing direction when reaching "0"
        while v == 0 and  CheckButton(DOWN) :    
            wait (100)
  
    if CheckButton(STOP): 
        v = 0
        drive()
        wait (100)    
        
class setprofile():
    def __init__(self,pr):
        self.vmin=pr[0]
        self.vmax=pr[1]
        self.step=pr[2]
        self.acc=pr[3]

profile = [0,0,0]
profile[1] = setprofile(Profil_A)
profile[2] = setprofile(Profil_B)

# -----------------------------------------------
#  function 2
# -----------------------------------------------
           
'''
def function2():
    if CheckButton(UP):
        timer[1].set(3000)
    if timer[1].check(): 
        print("Do something")
'''

# -----------------------------------------------
# general program routines and classes
# -----------------------------------------------

# ----CheckButton -------------------------------------------

def CheckButton(x):
    try:
        button = remote.buttons.pressed()
        if x == "A+"  : x = Button.LEFT_PLUS
        if x == "A-" : x = Button.LEFT_MINUS
        if x == "A0"  : x = Button.LEFT

        if x == "B+"  : x = Button.RIGHT_PLUS
        if x == "B-" : x = Button.RIGHT_MINUS
        if x == "B0"  : x = Button.RIGHT
    
        if x == "CENTER"  : x = Button.CENTER
        
        if x in button:
            return True
        else:
            return False
    except:
        return()

# ----delay -------------------------------------------

class delay:
    def __init__(self,id,time=0,watch=StopWatch(),busy=False):
        self.id=id
        self.time=time
        self.watch=watch
        self.busy=busy
        print ("Init Timer",id)
    # set a timer        
    def set(self,x):
        if  self.busy == False:
            self.busy = True
            self.watch.reset()
            self.time = x
            print("Timer",timer[1].id, "set to",x)
    #check if timer is reached, then return "True"
    def check(self):
        if self.busy == True:
            if self.watch.time() > self.time:
                self.busy = False
                self.time=0 
                print("Timer",timer[1].id, "stopped")
                return(True)
        else:
            return(False)

# ----drive -------------------------------------------

def drive():
    global vold
    global v
    print (v)
    if vold != v:
        # for each motor 1,2 
        for x in range(1,3):
            # set speed and direction
            s = v*round(motor[x].getDir())
            # real motor commands depending on motor type
            if motor[x].getType() == "Motor" :
                motor[x].obj.run(s*motor[x].getSpeed()) #  in 2.7
            if motor[x].getType() == "DCMotor" : 
                motor[x].obj.dc(s) 
            if v == 0 and motor[x].getType() != "---":  
                print("stop",x)
                motor[x].obj.stop()      
            #if motor[x].getDir() != 0 and motor[x].getType() == "DCMotor" : motor[x].obj.dc(s) 
        vold = v
            
# ----portcheck -------------------------------------------

def portcheck(i):
    # list of motors, 1 +2 contain string "DC"
    devices = {
    1: "Wedo 2.0 DC Motor",
    2: "Train DC Motor",
    38: "BOOST Interactive Motor",
    46: "Technic Large Motor",
    47: "Technic Extra Large Motor",
    48: "SPIKE Medium Angular Motor",
    49: "SPIKE Large Angular Motor",
    75: "Technic Medium Angular Motor",
    76: "Technic Large Angular Motor",
}
    port = motor[i].getPort()
    # Try to get the device, if it is attached.
    try:
        device = PUPDevice(port)
    except OSError as ex:
        if ex.args[0] == ENODEV:
            # No device found on this port.
            motor[i].setType("---")
            print(port, ": not connected")
            return ("---")
        else:
            raise

    # Get the device id
    id = device.info()['id']
    
    # Look up the name.
    try:
        # get the attributes for tacho motors
        if "Motor" in devices[id] and not("DC" in devices[id]): 
            motor[i].setType("Motor")
            motor[i].obj = Motor(port)

            #new in 2.7
            # if motor[x].getDir() != 0 and motor[x].getType() == "Motor" : motor[x].obj.run(s*motor[x].getSpeed()) #  in 2.7
            devs_max_speed = {38:1530,46:1890,47:1980,48:1367,49:1278,75:1367,76:1278 }
            dspeed = devs_max_speed.get(PUPDevice(port).info()['id'], 1000)
            motor[i].obj.stop()
            motor[i].obj.control.limits(speed=dspeed,acceleration=10000)
            motor[i].setSpeed(dspeed/100*0.9)

        # and set type for simple DC Motors    
        if "DC" in devices[id]:
            motor[i].setType("DCMotor")
            motor[i].obj = DCMotor(port)
            
    except KeyError:
        motor[i].stype("unkown")
        print(port, ":", "Unknown device with ID", id)
    wait(100)    
    print ("--")
    print(port, ":", devices[id], motor[i].getType(),motor[i].getSpeed(),motor[i].getAcc())

# ---- device  -------------------------------------------
    
class device():
    # store the device infos for each motor
    def __init__(self,port,dir):
        self.port = port
        self.dir = dir
        self.type=""
        self.speed=99
        self.acc=99
        self.obj=""
                
    def setType(self,x) : self.type = x
    def setSpeed(self,x): self.speed = x
    def setAcc(self,x)  : self.acc = x
    
    def getType(self)   : return self.type
    def getPort(self)   : return self.port
    def getDir(self)    : return self.dir
    def getSpeed(self)  : return self.speed
    def getAcc(self)    : return self.acc

# -----------------------------------------------
# globals
# -----------------------------------------------

v = 0
vold = 0
#remoteConnected = False

# -----------------------------------------------
# Ininitialize
# -----------------------------------------------

hub = CityHub()

#define timers
timer = [0,0,0]
timer[1] = delay(1)
timer[2] = delay(2)
           
#define motors
motor = [0,0,0]
motor[1] = device(Port.A,dirMotorA)
motor[2] = device(Port.B,dirMotorB)

# get the port properties
portcheck(1)
portcheck(2)    

# -----------------------------------------------
# remote connect
# -----------------------------------------------

hub.light.on(Color.RED)
print (hub.system.name())
try:
    remote = Remote(name=remoteName,timeout=remoteTimeout*1000)
except OSError as ex:
    hub.system.shutdown()

# -----------------------------------------------
# main loop
# -----------------------------------------------

while True:
   
    # --check if remote is connected ---------------------------------
    
    try:
        button = remote.buttons.pressed()
        hub.light.on(LEDconn)
        remoteConnected = True
    except OSError as ex:
        hub.light.on(LEDnotconn)
        print("Remote not connected")
        remoteConnected = False
       
        if watchdog == True:
            v=0
            drive()
        try:
            # reconnect remote
            remote = Remote(timeout=1000)
            wait(100)
            print("Remote reconnected")
            remoteConnected = True
        except OSError as ex:
            print("Remote not connected")

            
    if CheckButton(SWITCH):
        mode = mode+1
        if mode > 2: 
            mode = 1
        print (mode)
        if mode == 1 : remote.light.on(LED_A)
        if mode == 2 : remote.light.on(LED_B)    
   
        while CheckButton(SWITCH):
            button = remote.buttons.pressed()
            wait (100)

    if mode == 1 : function1()     
    if mode == 2 : function1()
    
    wait(10)

 

 

 

 

Edited by Lok24

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