It’s amazing what a person can get when they take interest in interesting free stuff: boxes of electrical parts , old computers, or in this case industrial robots. A friend of mine’s dad works for PVI, a company that does interesting things with video. They developed one version of the system used to make the “first down line” appear on TV in (American type) football games. Her Dad got these robots which were part of the Eye Vision system CBS used in the 2001 Super Bowl. The robots are Pan/Tilt bases that cameras were mounted to, so that the multiple cameras’ pictures could stay synced even with pan and tilt.

The bases, which have two axes of motion controlled by AC servo motors, are neat in and of themselves. What’s even more interesting (In my opinion) are the control boxes. Inside is all the equipment needed to run the robot base, and, from what I can tell, the camera as well. There’s a large black box which seems to convert video signal to fiber optic and an SBC (Single Board Computer) which controls the robot arm. Then the rest of the box is just power supplies for everything.

After obtaining a power cable for the control box, I hooked up an Ethernet cable to it and ran tcpdump to see if I could get any traffic to determine it’s IP address. I found the IP in an ARP request and after port scanning it, I was able to successfully login through telnet. It runs VxWorks which is a Unix like RTOS (Real Time Operating System), though it has a very interesting problem. Since it’s a Unix-like, I should be able to do an ls, and see some files or something (and this has been confirmed by online publications). Instead ls hangs as does cd and other file system commands. It’s like the file system is corrupt, except that it still boots. This is making the task of figuring out how VxWorks controls the robot arms extremely difficult. Peering at the files on the compact flash card from a normal computer makes things even more interesting. It’s DOS. At the time of this writing I still havn’t figured out what is going on, and documentation for VxWorks on the internet is sparse.

I’ve pretty much exausted my options exploring the current operating system on the box, so my next attempt will be with Linux on the SBC. The robot bases are controlled from the control box via ARCnet, one of the first local area network standards. Unfortunately, I don’t have any ARCnet interfaces on anything but the SBC’s, so I have to use them, but luckily the Linux kernel has an ARCnet driver built right in, so I’m hoping it works.

Once I get the bases working, my first project idea is to mount a camera to the bases and do motion tracking. Then I could attach a water gun to the bases as well, with a servo trigger and, well, get motion wet. Halloween is coming up :)