OK, the sensortrak is moving on nicely and now I've added a new robot to the nest.
It's an ER-1 from evolution and I just assembled it today and am going through the learning curve with it's basic stuff.
In case you don't know, the ER-1 is an Xbeams (xbeams.com) framed robot that uses your laptop for its brains. It connects to the USB ports of your laptop and has image recognition built into it and a primitive obstacle avoidance system using a second camera.
It comes with a controller board for two stepper motors that are each about 8 cubic inches(2x2x2) in size to move it about and a 5AH battery, webcam and charger. The 5AH battery is supposed to be able to move the robot for a few hours, but the real limitation is the laptops power.
My normal power usage is about 2 hours. On the robot, it is 15-20 minutes. This is due mainly to the 1 amp drain from the cameras, which get their power off the laptop. This has prompted some to add a 7AH battery to the machine. There are some positive reports from doing this and no doubt I will be adding one too. In fact, I will probably add an inverter so the laptop will run longer too. Haven't seen any numbers for the power loss through these inverters. I'm sure it's hefty, but it's simple and the batteries can be hot swapped out when they are drained allowing the robot to run continuously. Several of us are collaborating on a power nest and I'm thinking it might be nice to develop a robotic battery changer so when the battery level gets low, it heads for the nest, gets a new battery and goes about its business.