Hello, I’m wondering, I think the NXT LEGO processor comes with a bluetooth thing, so I would like have to buy only a 30$ D-link (they have a list of ones that wok) kinda dongle and would manage to make it work? anyone tried this before?
And, lets say I have this projet :
-creat a rover with the LEOG NXT
-add a WebCam on the LEGO NXT
-and send the video to my computer, process the image and send back info on what to do with the LEGO motors and evrything.
I know I can receive and send info to the lego just by buying one of the things I told about above, but what about the WebCam? how can I send the video?
A webcam would probably be a different wireless system, probably WiFi. You’d need some kind of software to capture the images and send signals to the bot. If you’re on Windows, you might want to check out RoboRealm.
yea it does, i almost got that thing before, but i entered the FIRST lego league and got to use it, but its not very good cause the batteries do dead in like 2 min
Watch out though if you use Bluetooth as well as Bluetooth uses the same frequency and you may get a lot of interference. They are also available in 1.2GHz
Tillin is right, try roborealm for your video handling. Its free so its no loss…
for roborealm, I count on using it already or maybe some of my own software (I have to make it first ). but its realy the fact, how can I sen the info to my computer WI-FI? and then I would send back the info bluetooth… it would work no?
To use WiFi you would probably have to learn how to use sockets and your favorite programming language, to communicate. I have done this in Python now, with a client program on one computer and a server program on another computer (but they could be on the same computer too). I at least understand the very basics of network communication now.
To do any real data transfer, you would need some kind of protocol regardless of the wireless hardware you use to connect everything. You could use Bluetooth, or ZigBee, or any of a number of other wireless setups including WiFi, which has the advantage of being able to transfer much more data much faster than most of the others. It just depends how much work you want to do on the software side.
Unless you are sending MUCH more data in one direction than the other, you should use the same wireless setup for both directions. However, you could use a Bluetooth link for sending commands and not too much data, and then use WiFi to send your main datastream, such as video, back and forth. Your video feed could be one way - to the larger PC where it would be processed, perhaps by RoboRealm.
You can use Bluetooth and ZigBee in transparent mode, as a simple wireless cable replacement.
There are a number of ways to get the video back to your computer wirelessly, but some are simpler than others.
The least complex, units, from a wiring point of view, will probably be integrated camera/transmitter units, often sold as wireless security systems. These are usually in the form of a single-piece camera/transmitter unit, to which one need only apply an appropriate power source. The receivers for these units will usually provide a composite video or S-video output, which would then be fed to the computer through an appropriate input port, such as those sometimes found on video cards, or some other sort of video-capture device that will accept a composite or S-video input to match the format of your wireless receiver. You can find wireless video transmitters that operate on various frequencies - if you’re planning to use Bluetooth for your control signals, you might look for a system that transmits on a frequency outside of and away from 2.45 GHz - the frequency range used by Bluetooth modules.
One of the disadvantages of using these one-piece units is that the transmitting antenna is attached to the camera module. As a general rule, the higher the frequency of a radio signal, the more it is affected by a change to the position of the transmitting and receiving antennas. If the camera is attached to a pan-tilt mounting, the quality of your signal may change, possibly quite dramatically, depending on the position of the pan-tilt mount.
There are other solutions for transmitting video wirelessly, but they’re generally more complex. You can get transmitter units that just take a standard composite video signal for input, and connect just about any video camera to it. Some transmitters will send a low-power signal a short distance to a TV tuned to some specific channel. These have the advantage of not requiring a separate receiver, so long as your computer is either connected to, or has an integrated TV receiver capable of tuning the proper channel. This also assumes that RoboRealm is capable of using your TV receiver as an image source for use with its image-processing capabilities.
A camera like the one Paul listed needs a 2.4 Ghz CCTV reciever base, and TV tuner card so the price isn’t quite representative. Man, if I have to buy anything from the UK I’m gonna get killed by the current exchange rate.
which is a bit steep at $140. If you want cheaper you can get the dcs-900w (802.11b version) for $75 or less.
Not only is the price all inclusive (assuming your PC has wireless or you have a wireless router), and the picture better (true 640x480), but if you have a large wifi network (office or school) with persistant IP, your bot can move around a lot more freely since as long as there is a datapath the images can get to the PC. Of course you’d also need someway to get commands to the bot (bluetooth has about a 100ft limit).
That one actually comes with a receiver for that price…
There is a company called pakatak that does a similar thing for about £45 with receiver but I got one from ebay with a slighter larger housing (that went in the bin) for £20
Agreed on the TV card though, Ive got 2 of these in my P.C.
I got stung on that as well, The unit I’ve got in my bot is class 1 so its good as you say for 100ft but the dongle they supplied for the other end is I think class 2 and only works for about 10ft…
I’m still not sure on his NXT bluetooth though, from what ive read on the lego site it looks like it may only work to their own dongle…
Wow…You’d think they would advertise that more. The only place I see reciever is buried in the specs. under reciever power. I guess its assumed they come with recievers? Anyway…
Bluetooth is 2.4Ghz and upgrading the antenna is very possible if you need a specific dongle pair. However, from the Lego FAQ:
Which really makes me think its okay to use just about any class 1 dongle. Yea, I never bought any brand names bluetooth dongles, just a $12 ebay one. I get 100ft with my BlueSMiRF, so I guess its class 1.
You can get an inexpensive Hauppauge TV tuner card with S-Video and composite video inputs for around $75.00 at NewEgg. Then you can use any kind of wireless camera you want as long as the remote receiver has either of those outputs. You could have a complete modular wireless video setup for around $140.00 US total.
Ive got one of those hauppage PVR systems, its useless, threw it in the corner about a week after I got the thing and thats where itll stay until I take a screwdriver to it…
Its a USB device and the audio was never in sync with the video
Bluetooth, ZigBee, WiFi (b and g), and others all operate in the 2.4 GHz band. They can actually all use the same types of antennas - it’s just a matter of the connection between the wireless module and the antenna. There are companies that make antennas and connectors to connect just about any wireless module to any antenna. The Cantenna would be my favororite for a 2.4 GHz directional antenna and it can be gotten with just about any type of connector you need. How about mounting a Cantenna on a pan/tilt base?
That’s just a cop out by LEGO so they don’t have to deal with any issues having to do with third party Bluetooth modules, and it’s just plain silly, mostly thanks to the legal profession. If it does not conform to the published Bluetooth standards, it is not Bluetooth and can’t be called Bluetooth for fear of legal ramifications. That said, the LEGO implementation of Bluetooth must meet the standards.
Any standard class 1 or 2 Bluetooth module should work just fine, or it can’t be called Bluetooth for reasons above.
From a radio standpoint, the thing that would worry me the most is front-end overload of the Bluetooth node on the remote end of the link, if the video transmitter was also operating in the 2.45 GHz band.
Even if it isn’t on exactly the same frequency, the transmitter operating on a nearby frequency, in physical proximity to the Bluetooth receiving antenna, could overwhelm the receiver and its amplifier stage, effectively blocking reception of the comparatively weak data link. If possible, I’d choose a video transmitter that operates in a different band than 2.45 GHz, to lessen the possibility of interference between the two systems.
Front-end overload and intermodulation can be major headaches in radio systems, when you’re trying to transmit and receive on nearby-but-different frequencies. The solution is often to simply operate in a “cross-band” mode, where the uplink and downlink frequencies are not only not close to each other, but in entirely different portions of the RF spectrum.
I fully disagree about the Bluetooth dongle. I mean, ideally the system would be coded to use standard bluetooth RS-232 and provide a wrapper. However, most commercial Bluetooth devices don’t do this.
I got one of those Chainpus chainpus.com/products/gamepad/bgp100.html Bluetooth gamepads for my PocketPC and it is just a micro with a BlueSMiRF-like chip, and some buttons. I thought it would be easy to hack, but it doesn’t use a normal serial port so I couldn’t capture input properly (there were no Windows XP, Windows Mobile, or Linux drivers at the time - Only Windows CE).
Also not all Bluetooth dongles are created equal. Most implement everything in software, but some don’t take standard M$/ Blue Solei/ BlueZ, software stacks. Again one of my projects was modding my PocketPC (Windows Mobile 5) to take the Windows CE Broadcom Bluetooth stack instead of the Dell Windows Mobile 5 one since the hardware could do A2DP and other more advanced Bluetooth stuff, but the software couldn’t.
I think LEGO is being smart since if they said works with any PC with bluetooth they’d get thousands of support claims and angry customers for the fault of cheap and defective Bluetooth dongles. This isn’t LEGO’s fault, and that statement gets it across that if it doesn’t work with your dongle, use ours.
Your probably not far off the point the tillin, the original concept for bluetooth was ‘your own personal network bubble’. It was part of the marketing strategy. Now its use has changed.
Its a standard disclaimer, “It should work but don’t come crying if it doesn’t”
wooo, a lot of post since my last visit. So, LEGO mindstorm comes with bluetooth and I could had my own antena on it so it would work better? Any antenas you know will work?
and, for sending the video one way to my PC from my WebCam, WIFI, what… how… mmm, Ok, I have a wireless D-link routerm could I use it to pick up the video? this isn’t realy clear in my head so explanation are very welcome
You could have a complete modular wireless video setup for around $140.00 US total.