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Keyboard Control¶

In this project, we will use w, s, a, d, i, k, j and l on the keyboard to control the PiArm.

../_images/keyboard_control.jpg

Shovel Bucket - Keyboard Coboardntrol¶

Run the code

cd /home/pi/piarm/examples
sudo python3 keyboard_control1.py

After running the code, follow the prompts and press the keys on the keyboard to control the PiArm’s arm and Shovel Bucket.

But you need to assemble Shovel Bucket on the PiArm first.

Note

  • To switch the keyboard to lowercase English input.

  • w, s, a, d, i and k are used to control the rotation of the arm.

  • j and l are used to control the angle of the Shovel Bucket.

Code

from piarm import PiArm
from robot_hat import Pin,PWM,Servo,ADC
from time import time,sleep
from robot_hat.utils import reset_mcu

import sys
import tty
import termios

reset_mcu()
sleep(0.01)

arm = PiArm([1,2,3])
arm.bucket_init(PWM('P3'))
arm.set_offset([0,0,0])
controllable = 0


manual = '''
Press keys on keyboard
    w: extend
    s: retract
    a: turn left
    d: turn right
    i: go up
    k: go down
    j: open
    l: close
    ESC: Quit
'''

def readchar():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(sys.stdin.fileno())
        ch = sys.stdin.read(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch

def control(key):

    arm.speed = 100
    flag = False
    alpha,beta,gamma = arm.servo_positions
    bucket = arm.component_staus

    if key == 'w':
        alpha += 3
        flag = True
    elif key == 's':
        alpha -= 3
        flag = True
    if key == 'a':
        gamma += 3
        flag = True
    elif key == 'd':
        gamma -= 3
        flag = True
    if key == 'i':
        beta += 3
        flag = True
    elif key == 'k':
        beta -= 3
        flag = True
    if key == 'j':
        bucket -= 1
        flag = True
    elif key == 'l':
        bucket += 1
        flag = True

    if flag == True:
        arm.set_angle([alpha,beta,gamma])
        arm.set_bucket(bucket)
        print('servo angles: %s , bucket angle: %s '%(arm.servo_positions,arm.component_staus))


if __name__ == "__main__":

    print(manual)

    while True:
        key = readchar().lower()
        control(key)
        if key == chr(27):
            break

How it works?

def readchar():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(sys.stdin.fileno())
        ch = sys.stdin.read(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch

This function references the standard input stream and returns the first character of the read data stream.

  • tty.setraw(sys.stdin.fileno) is to change the standard input stream to raw mode, i.e. all characters will not be escaped during transmission, including special characters.

  • old_settings = termios.tcgetattr(fd) and termios.tcsetattr(fd, termios.TCSADRAIN, old_settings) and acts as a backup and restore.

def control(key):

    arm.speed = 100
    flag = False
    alpha,beta,gamma = arm.servo_positions
    bucket = arm.component_staus

    if key == 'w':
        alpha += 3
        flag = True
    elif key == 's':
        alpha -= 3
        flag = True
    if key == 'a':
        gamma += 3
        flag = True
    elif key == 'd':
        gamma -= 3
        flag = True
    if key == 'i':
        beta += 3
        flag = True
    elif key == 'k':
        beta -= 3
        flag = True
    if key == 'j':
        bucket -= 1
        flag = True
    elif key == 'l':
        bucket += 1
        flag = True

    if flag == True:
        arm.set_angle([alpha,beta,gamma])
        arm.set_bucket(bucket)
        print('servo angles: %s , bucket angle: %s '%(arm.servo_positions,arm.component_staus))

In this code, the control() function is created to control the PiArm by reading the key values on the keyboard.

  • alpha, beta and gamma refer to the angles of the 3 servos on the arm respectively, refer to: Angle Mode.

  • Press the w key on the keyboard, the alpha increases and the Arm will extend forward.

  • Press the s key on the keyboard, the alpha decreases and the Arm will retract backward.

  • Press the a key on the keyboard, the gamma increases and the Arm will turn left.

  • Press the d key on the keyboard, the gamma decreases and the Arm will turn right.

  • Press the i key on the keyboard, the beta increases and the Arm will raise up.

  • Press the k key on the keyboard, the beta decreases and the Arm will lower down.

  • Finally, use the k and l keys to control the angle of the Shovel Bucket respectively.

while True:
    key = readchar().lower()
    control(key)
    if key == chr(27):
        break

Call readchar() in the main program to read the key value, then pass the read key value into the control() function so that PiArm will move according to the different keys. key == chr(27) represents the key Esc key press.

Hanging Clip - Keyboard Control¶

Run the code

cd /home/pi/piarm/examples
sudo python3 keyboard_control2.py

After running the code, follow the prompts and press the keys on the keyboard to control the Arm and Hanging Clip of PiArm.

But you need to assemble Hanging Clip to PiArm first.

Note

  • To switch the keyboard to lowercase English input.

  • w, s, a, d, i and k are used to control the rotation of the arm.

  • j and l are used to control the opening and closing of the Hanging Clip.

Code

from piarm import PiArm
from robot_hat import Pin,PWM,Servo,ADC
from time import time,sleep
from robot_hat.utils import reset_mcu

import sys
import tty
import termios

reset_mcu()
sleep(0.01)

arm = PiArm([1,2,3])
arm.hanging_clip_init(PWM('P3'))
arm.set_offset([0,0,0])
controllable = 0


manual = '''
Press keys on keyboard
    w: extend
    s: retract
    a: turn left
    d: turn right
    i: go up
    k: go down
    j: open
    l: close
    ESC: Quit
'''

def readchar():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(sys.stdin.fileno())
        ch = sys.stdin.read(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch

def control(key):

    arm.speed = 100
    flag = False
    alpha,beta,gamma = arm.servo_positions
    clip = arm.component_staus

    if key == 'w':
        alpha += 3
        flag = True
    elif key == 's':
        alpha -= 3
        flag = True
    if key == 'a':
        gamma += 3
        flag = True
    elif key == 'd':
        gamma -= 3
        flag = True
    if key == 'i':
        beta += 3
        flag = True
    elif key == 'k':
        beta -= 3
        flag = True

    if key == 'j':
        clip -= 1
        flag = True
    elif key == 'l':
        clip += 1
        flag = True

    if flag == True:
        arm.set_angle([alpha,beta,gamma])
        arm.set_hanging_clip(clip)
        print('servo angles: %s , clip angle: %s '%(arm.servo_positions,arm.component_staus))


if __name__ == "__main__":

    print(manual)

    while True:
        key = readchar().lower()
        control(key)
        if key == chr(27):
            break

In this code, the control() function is created to control the PiArm by reading the key values on the keyboard.

  • alpha, beta and gamma refer to the angles of the 3 servos on the arm respectively, refer to: Angle Mode.

  • Press the w key on the keyboard, the alpha increases and the Arm will extend forward.

  • Press the s key on the keyboard, the alpha decreases and the Arm will retract backward.

  • Press the a key on the keyboard, the gamma increases and the Arm will turn left.

  • Press the d key on the keyboard, the gamma decreases and the Arm will turn right.

  • Press the i key on the keyboard, the beta increases and the Arm will raise up.

  • Press the k key on the keyboard, the beta decreases and the Arm will lower down.

  • Finally, use the k and l keys to control the opening and closing of the Hanging Clip respectively.

Electromagnet - Keyboard Control¶

Run the code

cd /home/pi/piarm/examples
sudo python3 keyboard_control1.py

After running the code, follow the prompts and press the keys on the keyboard to control the PiArm’s arms and Electromagnet.

But you need to assemble Electromagnet to PiArm first.

Note

  • To switch the keyboard to lowercase English input.

  • w, s, a, d, i and k are used to control the rotation of the arm.

  • j and l are used to control the ON and OFF of the Electromagnet.

Code

from piarm import PiArm
from robot_hat import Pin,PWM,Servo,ADC
from time import time,sleep
from robot_hat.utils import reset_mcu

import sys
import tty
import termios

reset_mcu()
sleep(0.01)

arm = PiArm([1,2,3])
arm.electromagnet_init(PWM('P3'))
arm.set_offset([0,0,0])
controllable = 0


manual = '''
Press keys on keyboard
    w: extend
    s: retract
    a: turn left
    d: turn right
    i: go up
    k: go down
    j: on
    l: off
    ESC: Quit
'''

def readchar():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(sys.stdin.fileno())
        ch = sys.stdin.read(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch

def control(key):

    arm.speed = 100
    flag = False
    alpha,beta,gamma = arm.servo_positions
    status = ""

    if key == 'w':
        alpha += 3
        flag = True
    elif key == 's':
        alpha -= 3
        flag = True
    if key == 'a':
        gamma += 3
        flag = True
    elif key == 'd':
        gamma -= 3
        flag = True
    if key == 'i':
        beta += 3
        flag = True
    elif key == 'k':
        beta -= 3
        flag = True

    if key == 'j':
        arm.set_electromagnet('on')
    elif key == 'l':
        arm.set_electromagnet('off')

    if flag == True:
        arm.set_angle([alpha,beta,gamma])
        print('servo angles: %s , electromagnet status: %s '%(arm.servo_positions,status))


if __name__ == "__main__":

    print(manual)

    while True:
        key = readchar().lower()
        control(key)
        if key == chr(27):
            break

In this code, the control() function is created to control the PiArm by reading the key values on the keyboard.

  • alpha, beta and gamma refer to the angles of the 3 servos on the arm respectively, refer to: Angle Mode.

  • Press the w key on the keyboard, the alpha increases and the Arm will extend forward.

  • Press the s key on the keyboard, the alpha decreases and the Arm will retract backward.

  • Press the a key on the keyboard, the gamma increases and the Arm will turn left.

  • Press the d key on the keyboard, the gamma decreases and the Arm will turn right.

  • Press the i key on the keyboard, the beta increases and the Arm will raise up.

  • Press the k key on the keyboard, the beta decreases and the Arm will lower down.

  • Finally, use the k and l keys to control the ON and OFF of the Electromagnet respectively.