A puzzle box gadget
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#The Chubby Tricorder Project


Overview goes here.

#Design Decisions

I cut some corners to accelerate development and minimize risk. I wanted to work a few weeks of "uh oh" into the timetable as well as be able to focus on the software and presentation. Namely:

  • I used an off-the-shelf microcontroller board: the Arduino. It's large and a little slow by microcontroller standards, but board bring-up is easy and there are hundreds of premade/pre-tested hardware accessory libraries.
  • I used no batteries. The printer eats a ton of power. I didn't want to spend money on hefty batteries, which would tempt prolonged use, which in turn heightens the risk of dead batteries at a critical time.
    • Edit: I used batteries. The puzzle's location changed from indoors to outdoors, so I hacked up a battery pack.
  • The case is a simple laser-cut acrylic box of a design similar to the InfoNinja and my nameplate using tabs, slots, and bolted mortise and tension joints. It's entirely right angles, greatly simplifying the design.


#Software Overview

Makes use of the Arduino IDE plus several 3rd party libraries:

  • screen
  • printer
  • button matrix


  • Determine pin connections.
  • Wire it up on the bench:
    • Test each device, individually:
      • For each external device, on by one, hook it up to the default pins.
      • Verify the library can communicate with the device.
      • Move the device to your desired final set of pins.
      • Verify the library can communicate on the new set of pins.
    • Test all devices in unison:
      • Start with one device, ensure it works.
      • Add another, ensure they work in tandem.
      • Add the next, etc.
  • Preliminary software
    • Boot sequence animation (and also print test output on printer?)
    • Data entry screen
    • "Incorrect" animation (with delay to help discourage brute forcing)
    • Several incorrect answers in a row has longer delay?
    • Each "correct" behavior (screen, printer)
  • Wireless
    • Transmitter and receiver Hello World
    • Integrate transmitter into design
    • Test with receiver
  • Enclosure (black 3MM acrylic)
    • Determine internal parts placement.
    • Preliminary laser cut pattern.
    • Left/Right sides symmetric/interchangeable?
    • Print on paper, verify parts fit, verify pieces interlock correctly.
    • Send to Ponoko.
    • Hole for reprogramming? "warranty void if removed" sticker?
    • Reinforce printer edge panel
  • Battery power
    • Get battery holder
    • Get batteries
    • Wire up to 2.1mm plug
    • Rewire RF to 5V regulator on Arduino
  • Final software
    • Image rotator with PIN entry
    • RF xmission while rotating images
    • Stages of image rotator
    • Easter egg(s)
    • Better comments
    • Licensing
    • Publish LCD assistant code separately?
    • Build the more permanent RF receiver device
    • Verify with RF receiver device
    • Verify that one easter egg that wasn't working at meeting
  • "Plan B" webapp
    • Basics
    • All content
    • Preload images - skipped; iPhone times out preloading and aborts JavaScript
  • Final documentation
    • Prepare github
    • Prepare website
    • Prepare narrative blog post
    • Prepare shortened URL
    • Insert shortened URL plus intro text into code as easter egg

#Away Kit

In the event of a problem during the game, I'll need to assemble an "away kit" with various repair tools.

  • allen wrench
  • needle-nose pliers
  • diagonal clippers
  • multimeter
  • soldering iron, solder
  • helping hands


The Chubby Tricorder (https://github.com/BrianEnigma/chubby-tricorder)by Brian Enigma (http://netninja.com) is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License: http://creativecommons.org/licenses/by-sa/3.0/deed.en_US