Liz Quilty: Hacking the OWI robotic arm bot

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Liz Quilty:
Hacking the OWI robotic arm bot
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@ Kiwi PyCon 2013 - Saturday, 07 Sep 2013 - Track 1
http://nz.pycon.org/

**Audience level**

Novice

**Description**

Demonstrating the OWI robotic arm running automated with a Raspberry Pi and some python code.

**Abstract**

After buying my son an OWI robotic arm,we decided to see if we could do more with it than use the remote controller. We quickly found you can buy a USB interface, however it only came with windows drivers. After some googling we found we could control this with python scripts which led to even more fun!

**YouTube**

http://www.youtube.com/watch?v=UJUbOWDlbWs

Transcript

1. Hacking the OWI/Maplin Robotic Arm By Liz Quilty
2. Confession I don’t really know python. My way is possibly not the best I just like making things, and having fun :)
3. Items Required 1 OWI/Maplin Robotic Arm kit
4. Items Required 1 USB kit for the arm
5. Items Required 1 Raspberry Pi + power/network etc
6. Items Required A sick/bored child to assemble robotic arm
7. Setup Your Raspberry Pi Partition and install raspbian http://elinux.org/RPi_Easy_SD_Card_Setup Unpack this to the SD card as instructed Set up networking and connect via SSH
8. Adding Dev rules Create the file /etc/udev/rules.d/85-robotarm.rules with the contents SUBSYSTEM=="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 group usermod -aG plugdev www-data usermod -aG audio www-data
9. pyUSB Install the custom pyUSB pyusb 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
10. Command Line Quick and easy https://github.com/lizquilty/roboticarm/ Better for more complex stuff https://github.com/peterlavelle/maplinarm
11. 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)
12. Moving MoveArm(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
13. Demo Hello World + Waving PIR sensor connected to + - and pin GPIO pin 18 Sensor detects movement, greets and waves, then waits
14. Test and use Test the arm as root Pick up things, write some code, automate ! Use cron for time based sensors (motion) http://learn.adafruit.com/adafruits-raspberry-pi-lesson-12- sensing-movement/hardware http://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/configuring-gpio Speech - festival Voice control
15. Web Based Install apache & configure with CGI https://github.com/lizquilty/roboticarm/
16. Simple UI
17. Demo • Connect to the Wireless Access point RoboticArm • Browse to http://10.0.0.2 Try not to overload it :)
18. Speech Python http://cmusphinx.sourceforge.net/ Google http://blog.oscarliang.net/raspberry-pi-voice- recognition-works-like-siri/
19. References My GitHub https://github.com/lizquilty/roboticarm/ CLI scripts https://github.com/peterlavelle/maplinarm PyUSB http://sourceforge.net/projects/pyusb 99 little bugs in the code 99 little bugs in the code Take one down, patch it around 117 little bugs in the code