Odds & Ends

Mindtribe Hack Day: Robots and Polargraphs

Recently MindTribe held our very first hack day!  We took a day off to build a drawing robot inspired by the polargraph.  It was an opportunity for us to work together as a company, working on a single project (we usually split up into smaller, disparate teams for our client projects).  Also, it allowed to us to flex our interdisciplinary engineering muscles and take on different roles: electrical engineers masqueraded as mechanical and some ME’s took to firmware. Video here. Lessons learned:Chant “minimum viable” all day long. That’s what carried us through to completion.  Jerry repeatedly mentioned, “If we can just get it to draw a straight line, I’d be pretty happy.” Steve also added, “Asking ‘Is this minimum and viable?’ as a group was far more effective than simply asking that question to only yourself. If I had something in my mind I thought was pretty minimum, taking the step of running it by the group almost always resulted in something even more minimum and viable.” Yes, we left out tons of features: – Lifting the pen on and off the canvas with a solenoid. – Uploading an arbitrary picture and vectorizing it.  We framed our goal to the simplest denominator – the drawing program simply took in a list of (x,y) coordinates. – Add limit switches so the pen doesn’t run off the canvas and we can let it draw unattended. – Put the board on an adjustable stand with wheels.  To hold it up, we wedged the drawing board between two picnic tables and a couple of trash cans instead. But more importantly, we got it done in a day.  Done and usable is better than perfect. – Don’t build it yourself if it already exists. Jerry: “While it was fun and would have been more rewarding if we’d gotten it working, the Arduino-based stepper controller did not deliver in the limited time we had, since we had to take time to solder up the motor shield.  The pre-made, tested stepper controller from Peter Norberg Consulting ultimately delivered.  When you’re trying to get something done as fast as possible, you should seriously consider sourcing (with the usual caveats of finding reliable vendors, good support, etc.).” – Python is cool!  Pair programming is fun! “… although I’m not sure if what I was doing was really pair programming or just back-seat driving while Adam and Sravan programmed.” – Sam – Hang wall clocks more securely. (No comment.) – Build in parallel. By the time the electrical and firmware teams were ready to test drawing coordinates, the mechanical team was still building up the drawing board and stepper motor support beam.  Instead of waiting on the mechanical team to finish, they decided to prototype on a whiteboard, with lots of sticky tape.  Surprisingly, not much code needed to be adjusted from the move to whiteboard to the actual drawing board and saved us much time! – When in doubt, always buy more spare parts. The final design required 2 stepper motors, so we thought 2 extra stepper motors (4 total) would be enough.   Turns out we were wrong, since we worked in parallel.  The electrical team had to haggle with the mechanical team, who bargained with the firmware team, over the ownership of the stepper motors. Overall, very fun and successful hack day, so we’ll be doing this again soon!