Controling a remote device via internet

thecheat · Post by **thecheat** » Thu 01 Nov, 2007 8:21 pm

Hey, I was curious, I've got a project I'm starting (a "web cam bot") that I want to be controllable via the internet.

Basically the idea is to have a live broadcast from a laptop with a wireless card. Through some basic programming (may need help there, but that's later on, not there yet) have a few motors and such that would be controlled.

The key is that the live broadcast would be embedded into a web page, where you'ld have controls you could send the "web bot" It's been done before... but since you guys are the programmers, anyone know of anything/anyway to send/receive commands over the internet?

PS: if you don't get the drift, think RC car you could control from say africa via the internet. How would I do that via a web page and flash or... something...

King Harold · Post by **King Harold** » Thu 01 Nov, 2007 9:04 pm

<just an idea>
could you just use standard HTTP commands? POST commands?
</just an idea>
not much of an idea, but at least all browsers know how to do a simple POST, so there probably won't be any trouble on that end.. On the other end, you'll need to catch and process the command of course, but how hard can that be? (let's hope your server lets you do this)
otherwise
<other idea>
anything server-side that has even a bit power will somehow be able to execute programs and perhaps even provide input for them, that would make it almost too easy to be fun though, except it will also have to accept user-input of course
</other idea>

ok I know, stupid ideas..

thecheat · Post by **thecheat** » Fri 02 Nov, 2007 2:14 am

Hey, I'm open to anything right now... to be honest, I'm NOT a programmer...

I've tried, but linguistics is not my skill... and programming is definitely a language. Right now that half of the project isn't shaky, it's just not there period. Trying to patch the holes in the project, but that one is wide open to hard vacuum.

Again though, the idea is you log into my site (which is currently theoretical atm

) and depending on how I work it out... you basically are re-directed to a web page where you have a live video feed, and controls for the bot.

It'd be cool if it could be done with the arrow keys/ wasd keys, but even clickable keys would be ok.... (which would be what you were talking about, right?)

PS: more detail on the "other idea" ?

PPS: another cool idea would be to have a "queue line" where you enter your commands, how long, etc, then press "go" and watch it run. That'd probably be an even better idea unless someone can think of a faster way to transmit the webcam signal... it's got an 8 second delay currently...

Post by **Dwedit** » Fri 02 Nov, 2007 3:22 am

Lego mindstorms?

Timendus · Post by **Timendus** » Fri 02 Nov, 2007 8:59 am

I've been thinking about making something similar for my ehm... "dorm" is the proper English word I guess...

My initial idea for a proof of concept system was to write a Perl script that controls the parallel port of my webserver, and make requests to that script over the web, with the GET/POST variables indicating what the script should be doing to the parallel port. Then I could connect a bit of hardware to the port which controls turning the camera, and on the user side of things I was planning to let a few XmlHTTPRequests (you know, "Ajax") handle the requests to the perl script without leaving the page where the webcam stream is.

Provided that you don't have too much delay between pressing a key and seeing the webcam image rotate, that should work nicely for a first demo. And with Javascript you could also bind the buttons for rotating the webcam to keys on your keyboard.

thecheat · Post by **thecheat** » Sat 03 Nov, 2007 3:42 pm

The only problem that's a real struggle, is the fact that so far, that 8 second delay is a real nuisance... I can't help but feel that perhaps if you used a video conference or something there would be only a second or so of lag...

I mean, you play MMORPG's online and there isn't lag... there's got to be a way to cut it.

PS: dwedit... I'd like to, but I don't have any, and I'd like to use a computer if I could. make it more accessible to the public.

Timendus · Post by **Timendus** » Tue 06 Nov, 2007 11:40 am

How do you stream the video?

thecheat · Post by **thecheat** » Tue 06 Nov, 2007 5:23 pm

I'm using Windows Media Encoder....

you can see the stream here:

mms://thecheat.myvnc.com:1755

I'm using no-ip.com currently to provide a stable (semi?) safe ip address...

that help any?

King Harold · Post by **King Harold** » Tue 06 Nov, 2007 5:39 pm

Well, as far as I can see, it just loads too slowly (so Windows Media Player buffers too far ahead and even pauses at times)

thecheat · Post by **thecheat** » Wed 07 Nov, 2007 12:58 am

That's the current issue.... I'm not sure how to embed... and I'd like to get rid of the buffering. Maybe a second delay would be ok... but 8 seconds??? I mean seriously...

I'm assuming you DID see a feed, though, right?

hmm... anyone know where I should look to look into the programming of something like this?

Timendus · Post by **Timendus** » Wed 07 Nov, 2007 9:30 am

I wouldn't start writing your own streaming media server any time soon

You'll need an intermediate server because you don't have a static IP/direct connection, appearently. You can do it the old fashioned way and install one of the many crappy little applications that grab a frame from your webcam every X seconds and upload it to an FTP server. Then on your website you can use a bit of Javascript to refresh the image at the same speed, and you've got something kinda like video

I've used this a lot a few years ago and it's really quite simple to set up, and the delay is no more than the worst case scenario of 1 second plus network latency. Of course the frame rate sucks ass.

The other way I've been experimenting with is VLC media player. This excellent piece of software also contains a streaming media server (VLM) that you can configure to use your webcam (and microphone, if you want) as inputs, and stream them in any encapsulation and compression to a specific server or broadcast onto the network. Of course, this only works as far as the nearest firewall that blocks UDP or broadcast traffic, or as many hops as you set the broadcast to. It worked quite nicely on our university campus, but you want to use it on a website, so that could be a bit more tricky. But I think I remember it having options for that too, so I think you should take a look at it. On our network the stream quality was excellent, and the delay about a second. VLM can also forward a stream that it receives from the network, so that should work with your intermediate server thing mentioned above...

Those are the two methods I've been playing with, and that have proven useful. Of course there are hundreds more. I'd stay away from anything that's named "Windows Media Something" though

thecheat · Post by **thecheat** » Fri 09 Nov, 2007 3:17 am

last point = double yes...

works pretty good...

Anyways, I think that's a static/direct IP connection... or atleas that's what no-ip.com claims...

I'll look into VLC though... ANYTHING to get a quicker response time! (minus actually paying money... the webcam cost 10 bucks... at the store...)

thecheat · Post by **thecheat** » Sun 11 Nov, 2007 2:43 am

Hmm... I couldn't figure anything out with vlc... hmm... I'm going to see if I got an older version... .8?

Timendus · Post by **Timendus** » Mon 12 Nov, 2007 2:49 pm

Check this out:
http://www.videolan.org/doc/streaming-h ... /ch05.html

It's a bit tricky, with it being a new feature without a GUI and some half working features, but it's powerful and fairly stable once up and running.