Today was a focused effort on multiple parts of the project.
Chris and I worked on getting the actuators mounted, which wasn't too hard because the Firgelli actuators were a close fit in place of the coilovers. Except for one collision. The RC truck has an aggressive 4-link triangulated front and rear suspension geometry, built for stability in extreme rock-crawling conditions. The two upper links blocked the actuators but we got around it by flipping the upper links. Gave up a slight amount of ground clearance at the centre, but it made for a great fit! No need for any modifications to the mounting points, which helped speed things along.
After Dom completed the open house organizational forms, we started working on getting the Perception package (basically Point Cloud Library + frills) running through ROS on the Pi. Our initial plan was to build it from source, since the default ROSberry Pi configuration didn't officially support the PCL package. Knowing this would be a lengthy endeavour, we looked into cross-compiling via another Ubuntu instance. After hitting some snags, I stumbled upon an option that we hadn't known about before. Since the new Raspberry Pi 2 has an ARM processor, there is finally a way to run regular Ubuntu instead of Raspbian or other RasPi-specific distros! Time to change gears.
Chris got the actuators going using an arduino, but it required a voltage divider to step the 5V digital PWM output to 3.3V for the RasPi. Not a huge issue, but added complexity and more wires in a breadboard with sketchy connections to begin with. Luckily, we found that the RasPi has 3.3V GPIO (took too long to check!) and so we move away from the Arduino to start setting up PWM control on the Pi. Which meant we first needed to get ROS working on it!
This took a few hours and taught me a lot about how low-level Linux can be. I've been used to always having a desktop at least, but in this case I went as minimal as possible to fit everything on the smallish SD card and keep it relatively quick for the Pi. Bare bones Ubuntu 14.0.4.2? Better be good with vi! Well, I immediately got hit with SD formatting problems, network issues, package dependency errors, one-off unresolved bugs and then finally got it installed! Lesson learned? Never gloss over a step that doesn't make sense, just because you "might be able to get away with it". You won't.
Big shout out to Stack Exchange and the whole community around Ask Ubuntu, and the wiki contributors of the world! Honestly... the only reason we can have nice things.
Finally, we're getting close to running everything on a stand-alone system! Next steps for us are wrestling with the Kinect drivers on the Pi, getting the rear actuators installed and getting a PWM manager working in ROS that can leave processing room for PCL functions!
-D