So the Cellbots team were at Google’s Cloud Robotics shipping container, prepping a demo of an “Antlerbot” – an RC car controlled by a Nexus One connected to a Sparkfun IOIO board – when disaster struck: the Antlerbot ran up under one of the doors of the shipping container, which was just too high for the sensors – but just low enough to hit the upper chassis smack in the window that showed off the IOIO board … shorting out the car beneath.
So Chaitanya, Arshan, and Charles worked hard to get the bot running again, transplanting the brain from the shorted bot over to the larger Antlerbot which was going to be running on a tablet. After some surgery, they got the bot rewired, but the output was still bad: the IOIO was fried too.
Then they replaced the IOIO board, and still no luck: the new board wasn’t outputting the right signals. It turns out the board was on the wrong firmware version! Chaitanya, the Antlerbot developer, had to go, so Charles, the Cellbots code lead, took over. The source control server with the right code was down, but JP, a random Googler, swooped in to save the day with a laptop full of the right source code he’d downloaded just that morning.
That still didn’t do the trick, and it wasn’t until next morning that Arshan diagnosed the problem: the old brain on the new frame was having brownouts. Once that was fixed, the Antlerbot was free to roam the Maker Faire and delight children and adults alike:
So we had real making at the Maker Faire! Go Cellbots!
UPDATE: Charles pointed out we left out one of the coolest parts of the Sunday heroics. Charles discovered that he could get a split second of control after
connecting the robot before the controls would fail (AKA the “life twitch” moment).
The disconnection looked normal on the Android end, and Arshan correctly guessed that it was a brownout issue caused by the steering controller which was disconnecting the IOIO board.
However, there was still the big problem: “How do we do this without steering?” Arshan’s solution was to hack a USB cable so that we could use a spare portable USB charger to power the steering controller and take it off the powersource that the IOIO was running. So the Antlerbot was actually running off of two separate batteries with USB cable that had been modded right there. Hacky, yet very cool, and the type of resourcefulness sums up the Maker Faire spirit quite well.
Incidentally, this second power supply was the reason the bot began to fail to turn at the end of Sunday: Anthony wasn’t there for the second hotwiring, and therefore didn’t know he needed to charge that battery before the final run. Still, it was a great success and we look forward to next year!