Memory function

PiArm provides a function to record actions, which allows PiArm to do some repetitive actions automatically.

In this project, let’s see how to implement this function.

Run the code

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

After the code is run, you can use the left and right joystick to control the rotation of PiArm and the Shovel Bucket (But you need to assemble Shovel Bucket to PiArm first), press the left joystick to record one movement of PiArm, after recording several sets of movements, you can press the right joystick to make PiArm to reproduce these movements.

Only record the changes between points, if the starting point and the end point are the same, and you do many moves in between, but only press once to record, it will go directly from the starting point to the end point, and will not record the middle process.

Code

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

t = TTS()
reset_mcu()
sleep(0.01)

leftJoystick = Joystick(ADC('A0'),ADC('A1'),Pin('D0'))
rightJoystick = Joystick(ADC('A2'),ADC('A3'),Pin('D1'))

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

def _angles_control():
    arm.speed = 100
    flag = False
    alpha,beta,gamma = arm.servo_positions
    bucket = arm.component_staus
    global i

    if leftJoystick.read_status() == "up":
        alpha += 1
        flag = True
    elif leftJoystick.read_status() == "down":
        alpha -= 1
        flag = True
    if leftJoystick.read_status() == "left":
        gamma += 1
        flag = True
    elif leftJoystick.read_status() == "right":
        gamma -= 1
        flag = True
    if rightJoystick.read_status() == "up":
        beta += 1
        flag = True
    elif rightJoystick.read_status() == "down":
        beta -= 1
        flag = True

    if rightJoystick.read_status() == "left":
        bucket += 2
        flag = True
    elif rightJoystick.read_status() == "right":
        bucket -= 2
        flag = True

    if leftJoystick.read_status() == "pressed":
        arm.record()
        t.say("record")
        print('step %s : %s'%(i,arm.steps_buff[i*2]))
        i += 1
        sleep(0.05)
    elif rightJoystick.read_status() == "pressed":

        t.say("action")
        arm.set_speed(80)
        arm.record_reproduce(0.05)
        arm.set_speed(100)

    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(arm.servo_positions)
    i = 0
    while True:
        _angles_control()
        sleep(0.01)

How it works?

In this code, let’s focus on the _angles_control() function, which is used to read the value of the dual joystick and then perform different operations.

1. control the movement of the Arm

if leftJoystick.read_status() == "up":
    alpha += 1
    flag = True
elif leftJoystick.read_status() == "down":
    alpha -= 1
    flag = True
if leftJoystick.read_status() == "left":
    gamma += 1
    flag = True
elif leftJoystick.read_status() == "right":
    gamma -= 1
    flag = True
if rightJoystick.read_status() == "up":
    beta += 1
    flag = True
elif rightJoystick.read_status() == "down":
    beta -= 1
    flag = True

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

• If the left joystick is toggled up, alpha increases and the Arm will extend forward.

• If the left joystick is toggled down, alpha decreases and the Arm will retract backward.

• If the left joystick is toggled to the left, gamma increases and the Arm will turn left.

• If the left joystick is toggled to the right, gamma decreases and the Arm will turn right.

• If the right joystick is toggled up, beta increases and the Arm will raise up.

• If the right joystick is toggled down, beta decreases and the Arm will lower down.

2. Control the angle of the Shovel Bucket

if rightJoystick.read_status() == "left":
    bucket += 2
    flag = True
elif rightJoystick.read_status() == "right":
    bucket -= 2
    flag = True

• Right joystick toggles to the left to allow the Shovel Bucket to rewind.

• Right joystick toggles to the right to extend the bucket outward.

3. Recording and reproducing actions

if leftJoystick.read_status() == "pressed":
    arm.record()
    t.say("record")
    print('step %s : %s'%(i,arm.steps_buff[i*2]))
    i += 1
    sleep(0.05)
elif rightJoystick.read_status() == "pressed":

    t.say("action")
    arm.set_speed(80)
    arm.record_reproduce(0.05)
    arm.set_speed(100)

• If the left joystick is pressed and the record() function is called to record the action, PiArm will say that it has recorded. The terminal will show the angle and the number of recorded moves at this point.

• If the right joystick is pressed, the record_reproduce() function is called to reproduce the recorded action, and PiArm will prompt to start doing the action.

4. Write the angles to PiArm

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))

Write the angle of the Arm and the Shovel Bucket to PiArm and have it rotate to those angles.

If you have the Hanging Clip or Electromagnet connected to your PiArm, you can modify the above code by referring to the following parts.

• Hanging Clip - Joystick Control

• Electromagnet - Joystick Control