Robot Challenge

BrickLink now has a parts list, with pictures, for the NXT (set 8527) here.
The catalog administrator there hasn't approved the parts list yet,
but I'm sure it's pretty close. BrickLink is a good place to pick up extra
Lego parts that you need. Check out the "Want List" feature. It's works
very well.

I finished the last two parts of Spike tonight.

When constructing, you might want to connect the cables before hooking the sensor assemblies to the main part of the robot. If you follow the instructions and wait until the last step, it is impossible, especially for the ultrasonic sensor.

First was adding the sound sensor. You can see it at upper-right in the picture. After programming, you clap and it will move. I had to lower the sound threshhold to make it more responsive, but it worked pretty well.

Then I added the ultrasonic sensor. The programming for this is a bit complicated, as the instructions zoom in a section, and you can't easily see where some commands go. Note that on your program, you can pan around with the pan toolbar button enabled.

Once I had the program corrected, it worked pretty well (and old Spike is not limping as badly today). If you move your hand in front of the sensor, it will (sometimes) strike at you. And meanwhile it avoids hitting walls, staying 30 inches (about 75 cm) away from them. It makes a sound when it strikes, but the speaker is not very loud, especially with the noise of the motors, so it is hard to hear.

Still, the most impressive bot so far.

Last night I was able to complete the second part of Spike, adding the tail. Construction was relatively easy, until near the end. Attaching the entire tail assembly to the robot base took some figuring out to determine where the attachment is made. And then connecting some of the wires is difficult once all the pieces are surrounding the base NXT. I think they could have done some more user testing to avoid issues like that with some minor re-designs, or re-arranging of instructions.

Still the tail action is impressive, how it bends down as the scissor mechanism extends. Quite clever. Unfortunately, my Spike does not travel in a straight line. It veers slowly to the right, so it never hits the ball that the instructions tells you to place in front of it on the test pad. No amount of checking if the legs are aligned helped on that score.

Have you gotten your Spike to go straight? How?