Mechanisms are always an adventure.
Shortly after class I began thinking about a mechanism I love that is becoming extinct. The Split-flap display is just awesome. The click-clack of the flaps, the motion when the text changes, they have a unique character and mechanical wonder. The displays were common at train stations and at Disney they used to be used for wait time boards but have been phased out in the recent years.
This seemingly simple mechanism was relatively challenging to build, even starting with an open source design.
I initially looked at this old date clock of my Grandfather's. It is a relatively simple mechanism, you press the button on top and it increments the day.
When it came to building this myself, things got pretty complicated.
I ended up using an annoyingly large amount of software: Illustrator, OpenSCAD, Skeinforge, Kokopelli, a Linux VM, 123D Make and 123D Design. I think I was so excited about making this that I didn't really stop to think of the difference between the work required to translate the open-source version into something that I could use vs. starting from scratch.
I ran into a few problems over the week.
Challenges with Stepper Motor
- The Adafruit motor shield was making steppers very loud and hard to control. At first I thought it was my servo but tested two others. From what I've researched it may have something to do with the speed of the I2C bus.
- Lucky I had an EasyDriver that I bought in 2012 but never opened. It's like magic. Combined with the AccelStepper library everything is buttery smooth now.
Challenges with Laser Cutter
- The poor thing is tired. It didn't cut through– I was able to recut some parts but ran out of time.
- When I went to make corrections almost no times were available. I snagged a 30 minute spot on Sunday but was thwarted by the L train deciding not to function. Even after I left an hour early (not even knowing the train was in a mood). But, now I've found this magical website.
Challenges with Materials
- Polypropylene in laser cutter is a pain. Also, the material that I found has branding on one side. I want to find a better material and book a longer time so I can cut it better. It sometimes sticks in place right now.
- Wrong sizes. Even after triple checking everything I still got caught up on this one. There's one significant advantage of working as a group, a second set of eyes.
- didn't fit together
Challenges with General Logistics
- The L sucks.
- Vinyl was hard to find, waiting on Amazon package, should have tried Canal Plastics
All things considered, although I feel a bit out of practice, I'm pretty happy I got a working prototype in one week!
Next steps if this can be explored for the midterm:
- Control logic/typography: What does the display say and why? Maybe combine the morse code concept?
- Vinyl Cut Letters: It's surprisingly hard to get Vinyl in NYC)
- Calibration: Perhaps a magnetic reed sensor)
- Enclosure/Construction: Going to try out OpenBeam, need more acrylic and a new material for the flaps