Nov 11, 2006

Sneeker

I wanted a bot that was low to the ground for a robot's perspective. This robot can be remote controlled using a 2nd NXT or using a program like OnBrick.

Now that I've got the bugs worked out, I'm going to use the RoboRealm software to control the NXT (via Bluetooth) based on input from the wireless camera and the Ultrasonic sensor. Also in the robot is one of the smallest cables - it's from HiTechnic and is approximately 4.75 inches (12cm) and I've used it to connect the Ultrasonic sensor to the brick. I didn't want to have to wrap another cable around, so this was a nice solution.

I call it Sneeker, but it is not very sneaky... the motors would give away its location if anyone was paying attention. The wireless camera is also static-mounted, parallel to the floor and does not move. I may try and add some functionality that allows the camera to swivel, but that would require adding a 3rd motor and I wanted to avoid another motor and keep the bot small and compact.

To view the feedback, I purchased a USB device that allows me to connect the wireless camera receiver to my laptop. Now I can control and watch my bot... or just let it roam on its own.

It's getting dark now, and the wireless camera doesn't do that well in low light, so I'll record some of its roaming around tomorrow and post a video.

12 comments:

Anonymous said...

I have a similar (if not the identical) camera, what USB device did you get to use as a receiver?

Jim Kelly said...

Yeah, the camera is fairly well known and recognized... and it fit perfectly to the face of a spare Light sensor housing :)

I bought the VideoXpress from ADS Tech... got it at CompUSA on sale. It's small and works great.

jim

Krystian Majewski said...

You use a blue ball as a third wheel? How does that work?

Anonymous said...

Jim, I like the design. Besides your bot help my phisical design of my bot named "mech1" because I want to improve the physical results when I execute rotate method with icommand.

JAB.

Jim Kelly said...

Pretty well... it's no big secret and has been used in many robot designs by others. I favor it for giving bots the ability to turn easier... I don't like casters and the basic NXT kit doesn't com with one (unless you make it).

Jim

Anonymous said...

Hi Jim. Thanks for all the good information.

I am new to the NXT world and don't recognize the camera. Can you provide more information on the wireless camera you're using?

thanks,
cw

Jim Kelly said...

Hi, CW.

A quick look at geeks.com shows that they don't appear to be selling this camera anymore... I bought it from them for $30US plus shipping...

Here's a previous post on the camera:

http://thenxtstep.blogspot.com/2006_10_01_thenxtstep_archive.html

I've found an older version of this camera on various websites and I remember some readers posting that eBay can be a good source for them.

I don't know why geeks.com isn't selling them anymore... when they sell out, they typically just put a "out of stock" on the webpage, but for this camera it appears they've removed the entire link to it.

Jim

Anonymous said...

Do you use the VideoXpress with the clunky receiver that came with the camera? or is it capable of tuning to the camera's freq?

Jim Kelly said...

It doesn't have tuning capabilities... so I have to use the clunky receiver. I'm looking for a small box or container that I can put everything in except for the antennae sticking up and the USB cable coming out... just to clean up the mess.

RoboRealm said...

Jim,

Let us know how it goes with RoboRealm. We're working on improving the ball tracking so things should get more reliable in the next release.

We also used the same camera and had issues with low light. For those who would like to get a similar camera you can check out http://www.sparkfun.com/commerce/product_info.php?products_id=745# but they only have 4 left!!

I really like the idea of using the ball as the castor! Probably works quite well over carpet.

STeven.

david said...

Tell us more about that Xpress. Does it act like a normal webcam? How can you program the computer to send BT commands to NXT by deciding on camera sight? for example balltracking (like Vision Command)

Jim Kelly said...

The RoboRealm software states that it can work with many different types of camera, as long as the signal is of a particular type (sorry, I'm not up on all the terminology).

When I connect the VideoXpress device to my laptop and open the RoboRealm software, the video from my wireless camera is live and displayed on the screen. (I'll add a new post shortly with a screenshot of the software running).

I haven't had any time yet to experiment with the programming portion of RoboRealm, but I have played with controlling the motors with the software and it does work (but it took me about 10 minutes to figure out how to get my Bluetooth laptop talking to my NXT - this happens every time I make the connection and is my only complaint about Bluetooth).

AS for the VideoXpress device - this is what I purchased:

http://www.adstech.com/products/USBAV-191-EF/intro/USBAV_191_intro.asp?pid=USBAV-191-EF

It works great... very small. As stated in earlier comment, my only complaint is all the wiring from the wireless camera's receiver... blah.

Jim

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