Monday, April 3, 2017

Giant Display and Home for my First Arduino

The extra large (6.5") seven segment display array pictured above has been at my desk for a long time now, but I never posted about it. Remembering how it came together is a fun walk through memory lane.

Central to this project is my very first Arduino. My boyfriend at the time bought it, spent an afternoon on it with a friend, and then decided he didn't want to do anything else with it and asked me if I wanted it. It is an Arduino Diecimila, and this must have been around 2008-2009, because I remember one of my first projects with Arduino was interfacing with an ultrasonic rangefinder and an optical encoder that year. It later become Swervy's brain. Memories of my freshman dorm remind me why students need hackerspaces:

I was a really bad roommate...I shared this room with my unfortunate roommate. The dividing line is supposed to be roughly in between the black backpack and black storage cube.

My 'hackerspace' at the time was a $99 refurbished Ryobi drill+circle saw, a $30 set of Ryobi drill bits,  a Radioshack soldering iron, and misc. things taken out of the dumpster from USC, along with some sensors I got from my FIRST robotics team and the aforementioned Arduino Diecimila.

Sophomore year of college, beginning of the spring semester, Sparkfun has a big promotional event/server load test. They were giving away one hundred $100 free orders (Sparkfun Free Day). I skipped that morning's Calculus lecture and hit refresh on the page until I won my free order. The four 6.5" red seven segment displays were in my cart for that order, along with a few other things including a Simon Says kit that taught me how to do surface mount soldering.

At some point in 2015 I dug up these parts and put it all together. The circuit is just a bunch of BJT transistors and some buttons to set the input. I never figured out what I wanted it to do, so I put it up on the wall and update it as a calendar, manually, whenever I come in to my office. The Arduino doesn't have enough output ports to handle all the digits at the same time so it enables/sets one at a time, repeatedly and very quickly. Very common solution to a common problem, but it was a fun afternoon project anyway. The wiring harness took the most time. I think I glued the whole thing to the wall with no consideration for whether I'd want to move it in the future. I'll have to tear it off the wall eventually, since Sector67 is getting a new building. Chris jokes sometimes that it looks like what the TSA might think is a bomb; this clock slightly predates the recent clock incident. Which also reminds me of this page which left a huge impression on me when I first read it in college and turned me into a fan.