maplinrobot.py

Python script to control the Maplin USB robotic arm on your Raspberry PI.

Requirements

• Raspian
• Python 2.7
• pip
• pyusb Library

Installation

• Create a new udev rules file at /etc/udev/rules.d/85-robotarm.rules with the contents

SUBSYSTEM=="usb", ATTRS{idVendor}=="1267", ATTRS{idProduct}=="0000", ACTION=="add", GROUP="plugdev", MODE="0666"

• Add your user to the plugdev group using the command:

  sudo usermod -aG plugdev yourusername

• Reboot the Pi with the command:

  sudo shutdown -r now

• Make the script executable with the command:

  chmod 755 maplinrobot.py

• Install pip with the command:

  sudo apt-get install python-pip -y

• Install pyusb Library via pip with the command:

  sudo pip install pyusb

• Open the script and edit it to suit your needs (See Example Usage section for more info.)
• type ./maplinrobot.py to run. If you have problems running as a normal user, try running the script as root.

Moving the Arm

Commands are stored in a dictionary. Valid commands to send to the arm are:

• 'base-anti-clockwise' - Rotates the base ant-clockwise
• 'base-clockwise' - Rotates the base clockwise
• 'shoulder-up' - Raises the shoulder
• 'shoulder-down' - Lowers the shoulder
• 'elbow-up' - Raises the elbow
• 'elbow-down' - Lowers the elbow
• 'wrist-up' - Raises the wrist
• 'wrist-down' - Lowers the wrist
• 'grip-open' - Opens the grip
• 'grip-close' - Closes the grip
• 'light-on' - Turns on the LED in the grip
• 'light-off' - Turns the LED in the grip off
• 'stop' - Stops all movement of the arm

Example Usage

-At the bottom of the script uncomment the lines below:

s = MaplinRobot()
s.MoveArm(t=1.0, cmd='base-clockwise')

This will rotate the base of the arm clockwise for 1 second. Duration of each command is set by passing a float value to the t parameter.

The argument passed to the cmd parameter can be any command in the Moving the Arm section above.