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Step 5Get a Video Feed
After your robotic explorer can drive wirelessly, you'll probably want to have a video feed from the netbook so you can tell where your robot is. If you're using Ubuntu (or even if you aren't!) I recommend using VLC Media Player to stream. If you haven't installed it, you're really missing out, so install it using the command "sudo apt-get install vlc", browse for VLC in the Ubuntu Software Center (9.10 only), or download the installer at videolan.org if you're on Windows. You will need VLC running on both PC's. VLC is capable of streaming as well as playing streams on a network. On the netbook (robot PC) first make sure your webcam (either built-in or USB connected) works by clicking Open Capture Device and trying Video for Linux 2 (some older devices may need Video for Linux rather than the new 2 version). You should see the camera's view on the netbook screen. To stream it, select Streaming from the File menu and then pick the Capture Device tab at the top of the window that appears. Remember that Ubuntu (and many other Linux distros) let you hold down Alt to click and drag windows that are too big for your screen (especially useful on older netbooks, though even my IdeaPad has an odd 1024x576 resolution for no apparent reason). To reduce delay, click on "Show More Options" and lower the caching value. The amount that you can lower it sometimes depends on the device, it gets unstable if you lower it too much. At 300ms you may get a slight delay but it isn't too bad.
Next, click Stream to go to the next menu. Click Next, then select and add HTTP as a new destination. Now set up Transcoding to make the stream smaller. I made a custom profile that uses M-JPEG at 60kb/s and 8fps. This is because using an advanced codec like MPEG or Theora will eat up massive CPU time on a netbook's Atom processor and this can lead to your video feed stopping for no apparent reason. MJPEG is a simple codec that is easy to use at low bitrates.
After starting your stream, open up VLC on your other PC, open a network stream, select HTTP, and then type the IP address of your netbook (either local or Internet depending on how you're connecting) followed by ":8080". You need to specify the port for some odd reason, otherwise it gives you errors. If you have a decent connection, you should see your webcam's feed on your other PC, but it will have a slight (about a second) delay. I don't know exactly why this delay occurs, but I can't figure out how to get rid of it. Now open up the control app and start driving your netbook robot. Get a feel for how the delay works when driving so you won't crash into anything. If it works, your netbook robot is finished.
Next, click Stream to go to the next menu. Click Next, then select and add HTTP as a new destination. Now set up Transcoding to make the stream smaller. I made a custom profile that uses M-JPEG at 60kb/s and 8fps. This is because using an advanced codec like MPEG or Theora will eat up massive CPU time on a netbook's Atom processor and this can lead to your video feed stopping for no apparent reason. MJPEG is a simple codec that is easy to use at low bitrates.
After starting your stream, open up VLC on your other PC, open a network stream, select HTTP, and then type the IP address of your netbook (either local or Internet depending on how you're connecting) followed by ":8080". You need to specify the port for some odd reason, otherwise it gives you errors. If you have a decent connection, you should see your webcam's feed on your other PC, but it will have a slight (about a second) delay. I don't know exactly why this delay occurs, but I can't figure out how to get rid of it. Now open up the control app and start driving your netbook robot. Get a feel for how the delay works when driving so you won't crash into anything. If it works, your netbook robot is finished.
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Could you please re-upload it ? Thanks !