CODEWITHSUNDEEP
htmllinux
Student
Student

Reputation: 463

Using a Webpage to Control Robot Arm Written in Linux

Firstly I am no longer a student and currently working on a favour for a friend. I am making a website which has a live video feed of a robotic arm and a set off buttons that will allow users with the basic interaction of the robotic arm.

I have setup the website and live video feed. I do have a 4 second delay using flash media encoder and flash server 4.5. Have any suggestions in reducing the delay time?

I have done the python code required for the maplin robotic arm and now I am stuck and not sure how to link my python code with a webpage interface? Can anyone that has done this before provide with code that I could edit and learn from..

Python Code

import usb.core
import usb.util
import sys
import time

# This program is intended to control a robotic arm via USB from Linux
# The code is written in Python by Neil Polwart (c) 2011
# It is a work in progress and will improved!

# locate the device device

dev = usb.core.find(idVendor=0x1267, idProduct=0x0000)

# assigns the device to the handle "dev"
# can check the device is visible to Linux with command line command lsusb
# which should report a device with the above vendor and id codes.

# was it found?

if dev is None:
raise ValueError('Device not found')           # if device not found report an       error


# set the active configuration

dev.set_configuration()

# as no arguments, the first configuration will be the active one
# note as commands are sent to device as commands not data streams 
# no need to define the endpoint

# defines the command packet to send

datapack=0x80,0,0

# change this packet to make different moves.  
# first byte defines most of the movements, second byte shoulder rotation, third           byte light
# command structure in more detail:
# http://notbrainsurgery.livejournal.com/38622.html?view=93150#t93150

print "requested move",datapack    # reports the requested movement to the user

# send the command

bytesout=dev.ctrl_transfer(0x40, 6, 0x100, 0, datapack, 1000)

# outputs the command to the USB device, using the ctrl_transfer method
# 0x40, 6, 0x100, 0 defines the details of the write - bRequestType, bRequest,    wValue, wIndex
# datapack is our command (3 bytes)
# the final value is a timeout (in ms) which is optional
# bytesout = the number of bytes written (i.e. 3 if successful)

print "Written :",bytesout,"bytes"  # confirm to user that data was sent OK

# wait for a defined period

time.sleep(1)    # waits for 1 second whilst motors move.

# now STOP the motors

datapack=0,0,0

bytesout=dev.ctrl_transfer(0x40, 6, 0x100, 0, datapack, 1000)

if bytesout == 3: print "Motors stopped"

So I need to find a way to edit the datapack line via a website interface. Any help is appreciated! I am using a Windows 7 setup but do have access to vmware

Upvotes: 1

Views: 758

Answers (1)

Brigand
Brigand

Reputation: 86220

I'd set up an Apache server with mod_python and create a handler that imports your script and runs the necessary code. You can set up an AJAX script in JavaScript (with or without jQuery). Every time you want to run the Python script, a request needs to be made to the server. You can pass any information back and forth as needed via the HTTP.

Here's a good tutorial for Python and the CGI Module.

Upvotes: 1

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