Robie the Robot lives!
A few days ago I put in the obstacle avoidance programming for the coasterbot. Almost immediately, he acquired a real personality. The algorithm works incredibly well. Even though the first version of my code had significant bugs — typos, forgetting that moving the sensor servo takes a finite amount of time, etc. — he was able to navigate quite competently. And after some corrections, he did even better.
There were some minor hardware issues I discovered. The Solarbotics voltage regulator had a high-resistance short which would cause the 9V battery to drain after a day or so, even if the robot was turned off. I was able to get rid of it but that drove me crazy for a while — I wondered why I had to keep recharging the battery!
Also, solderless breadboards have their limitations. The Ardweeny has a nasty habit of tilting in the board, disconnecting some pins and resulting in a robot that almost works; and manipulating the bot can make it tilt back, “fixing” the problem. Again, for a while I blamed the batteries until I figured out the true cause. Other breadboard connections would sometimes work loose, particularly for the PING sensor or servo. I soldered solid-gauge wire onto the stranded wires of the AAA case in order to make that connection more solid.
So, on to the fun stuff — a working robot! Here are some videos showing him in action.
Kids Playing with Coasterbot. The title says it all. The kids really had fun with this.
Official “Contest Entry” Video. Robie navigates his way around a room and out of some tight corners. I learned some features of Microsoft Movie Maker (free with Windows) in making this. Note the title sequence and credits. 🙂
I have written up a detailed summary of Robie’s construction and operation, including schematic, bill of materials, and more links to photos and videos. Please check that out if you want more information.