Control#

Introduction#

Control includes methods for timing, program flow, conditional logic, and project termination. These controls let you pause execution, create loops, define logic paths, and end a program. Below is a list of available controls, including methods and core Python keywords:

  • wait – Pauses execution for a given number of milliseconds or seconds.

  • for – Repeats code for each item in a sequence.

  • if – Executes code if a condition is true.

  • if/else – Runs different code depending on a condition.

  • if/elif/else – Checks multiple conditions in order.

  • while – Repeats code while a condition is true.

  • break – Exits a loop immediately.

  • program_stop – Ends the running program.

  • pass – Placeholder used when no action is needed.

wait#

wait pauses for a specific amount of time before moving to the next method.

Usage:
wait(time, units)

Parameters

Description

time

The amount of time to wait, as a positive integer.

units

Milliseconds MSEC (default) or SECONDS.

# Move the arm to the desired position and then blink the signal tower
arm.move_to(40, 140, 210, False)
wait(1, SECONDS)
signaltower_1.set_color(signal_tower.BLUE, signal_tower.BLINK)

for#

for iterates over a sequence (such as a list, tuple, dictionary, set, or string) or any iterable object. It executes the block of code once for each item in the sequence.

Usage:

for value in expression_list:
    pass

Parameters

Description

value

A temporary variable that stores the current element in the iteration.

expression_list

The collection of elements being looped through (e.g., list, string, range).

# Move the arm 4 times by 100 millimeters on the y axis
for index in range(4):
    arm.move_inc(0, 100, 0)

if#

if executes the indented block of code if the condition evaluates as True.

Usage:

if condition:
    pass

Parameters

Description

condition

An expression or variable that is evaluated when the statement runs. If it evaluates as True, the code inside the if block executes; if it evaluates as False, the block is skipped.

# Display the time until the move is completed
arm.move_to(-100, 200, 100, False)
while True:
    print("\033[2J")
    print(timer.time(SECONDS))
    wait(50, MSEC)
    if arm.is_done():
        timer.clear()

if/else#

if and else determine which indented block of code runs based on whether the condition evaluates as True or False.

Usage:

if condition:
    pass
else:
    pass

Parameters

Description

condition

An expression or variable that is evaluated when the statement runs. If it evaluates as True, the code inside the if block executes; if it evaluates as False, the code inside the else block executes instead.

# Display the time until the move is completed
arm.move_to(-100, 200, 100, False)
while True:
    if arm.is_done():
        timer.clear()
    else:
        print("\033[2J")
        print(timer.time(SECONDS))
    wait(50, MSEC)

if/elif/else#

The if/elif/else structure selects which indented block of code runs based on conditions:

  • if runs its block if the condition evaluates as True.

  • elif checks additional conditions only if all previous conditions evaluated as False. Multiple elif statements can be used.

  • else runs its block only if none of the previous conditions evaluated as True.

Usage:

if condition:
    pass
elif condition:
    pass
else:
    pass

Parameters

Description

condition

An expression or variable that is evaluated when the statement runs. The first condition that evaluates as True determines which block executes; if none are True, the else block runs.

# Change the signal tower light if arm can reach to the desired position
while True:
    if arm.can_arm_reach_to(200, 200, 200):
        signaltower_1.set_color(signal_tower.BLUE, signal_tower.BLINK)
    elif arm.can_arm_reach_to(300, 300, 300):
        signaltower_1.set_color(signal_tower.GREEN, signal_tower.BLINK)
    else:
        signaltower_1.set_color(signal_tower.OFF, signal_tower.OFF)
    wait(50, MSEC)

while#

while repeatedly runs methods as long as the condition is True. It can also be used like a “Wait until” by adding not to the condition, as shown in the example below.

Usage:

while condition:
    pass

Parameters

Description

condition

An expression or variable that is evaluated before each iteration. If it evaluates as True, the loop continues; if it evaluates as False, the loop stops.

# Display the time until the move is completed
arm.move_to(-100, 200, 100, False)
while True:
    if arm.is_done():
        break
    else:
        print("\033[2J")
        print(timer.time(SECONDS))
    wait(50, MSEC)

# Blink blue light until the move is completed
signaltower_1.set_color(signal_tower.BLUE, signal_tower.BLINK)
arm.move_to(-100, 200, 100, False)
while not arm.is_done():
    wait(0.2, SECONDS)
signaltower_1.set_color(signal_tower.BLUE, signal_tower.ON)

break#

break is a keyword that exits a loop immediately.

# Display the time until the move is completed
arm.move_to(-100, 200, 100, False)
while True:
    if arm.is_done():
        break
    else:
        print("\033[2J")
        print(timer.time(SECONDS))
    wait(50, MSEC)

program_stop#

program_stop ends a running project.

Usage:
brain.program_stop()

Parameters

Description

This method has no parameters.

# Stop the project until the move is completed
arm.move_to(-100, 200, 100, False)
while True:
    if arm.is_done():
        break
    else:
        print("\033[2J")
        print(timer.time(SECONDS))
    wait(50, MSEC)
brain.program_stop()

pass#

pass is a keyword that acts as a placeholder for future code and can be used to avoid errors in empty loops, conditionals, and functions.

if condition:
    pass

def function():
    pass