Hacking the OWI/Maplin Robotic Arm

By Liz Quilty

Confession

I don’t really know python.

My way is possibly not the best

I just like making things, and having fun :)

Items Required

1 OWI/Maplin Robotic Arm kit

Items Required

1 USB kit for the arm

Items Required

1 Raspberry Pi + power/network etc

Items RequiredA sick/bored child to assemble robotic arm

Setup Your Raspberry Pi

Partition and install raspbianhttp://elinux.org/RPi_Easy_SD_Card_Setup

Unpack this to the SD card as instructed

Set up networking and connect via SSH

Adding Dev rules

Create the file /etc/udev/rules.d/85-robotarm.rules with the contentsSUBSYSTEM=="usb", ATTRS{idVendor}=="1267", ATTRS{idProduct}=="0000", ACTION=="add", GROUP="plugdev", MODE="0666"

This allows non root users to access it.

For CGI add apache user to plugdev groupusermod -aG plugdev www-datausermod -aG audio www-data

pyUSB

Install the custom pyUSBpyusb http://sourceforge.net/projects/pyusb

# wget "http://downloads.sourceforge.net/project/pyusb/PyUSB%201.0/1.0.0-alpha-3/pyusb-1.0.0a3.zip?r=http%3A%2F%2Fsourceforge.net%2Fprojects%2Fpyusb%2F&ts=1377736820&use_mirror=hivelocity"# unzip pyusb-1.0.0a3.zip# cd pyusb# python setup.py build# python setup.py install

Command Line

Quick and easyhttps://github.com/lizquilty/roboticarm/

Better for more complex stuffhttps://github.com/peterlavelle/maplinarm

Setting up the functions#ROBOT ARM CONTROL PROGRAM

#import the USB and Time librarys into Python

import usb.core, usb.util, time

#Allocate the name 'RoboArm' to the USB device

RoboArm = usb.core.find(idVendor=0x1267, idProduct=0x000)

#Check if the arm is detected and warn if not

if RoboArm is None:

raise ValueError("Arm not found")

#Create a variable for duration

Duration=1

#Define a procedure to execute each movement

def MoveArm(Duration, ArmCmd):

#Start the movement

RoboArm.ctrl_transfer(0x40,6,0x100,0,ArmCmd,1000)

#Stop the movement after waiting a specified duration

time.sleep(Duration)

ArmCmd=[0,0,0]

RoboArm.ctrl_transfer(0x40,6,0x100,0,ArmCmd,1000)

MovingMoveArm(1,[0,1,0]) #Rotate base anti-clockwise

MoveArm(1,[0,2,0]) #Rotate base clockwise

MoveArm(1,[64,0,0]) #Shoulder up

MoveArm(1,[128,0,0]) #Shoulder down

MoveArm(1,[16,0,0]) #Elbow up

MoveArm(1,[32,0,0]) #Elbow down

MoveArm(1,[4,0,0]) #Wrist up

MoveArm(1,[8,0,0]) # Wrist down

MoveArm(1,[2,0,0]) #Grip open

MoveArm(1,[1,0,0]) #Grip close

MoveArm(1,[0,0,1]) #Light on

MoveArm(1,[0,0,0]) #Light off

Demo Hello World + Waving

PIR sensor connected to + - and pin GPIO pin 18Sensor detects movement, greets and waves, then waits

Test and use

Test the arm as rootPick up things, write some code, automate !Use cron for time basedsensors (motion) http://learn.adafruit.com/adafruits-raspberry-pi-lesson-12-sensing-movement/hardwarehttp://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/configuring-gpio

Speech - festivalVoice control

Web Based

Install apache & configure with CGI

https://github.com/lizquilty/roboticarm/

Simple UI

Demo

● Connect to the Wireless Access point RoboticArm● Browse to http://10.0.0.2

Try not to overload it :)

Speech

Python http://cmusphinx.sourceforge.net/

Googlehttp://blog.oscarliang.net/raspberry-pi-voice-recognition-works-like-siri/

References

My GitHub https://github.com/lizquilty/roboticarm/CLI scripts https://github.com/peterlavelle/maplinarmPyUSB http://sourceforge.net/projects/pyusb

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