Behold! A Chronoduino!

So, what’s wrong (in my humblest of opinions) with the MakerBot Watch? Well, nothing actually. And a lot of things. It’s not that it’s bad, it’s just that i want MOAR! And i want it smaller and with more features. And i’m impatient. So anyways, here’s what i didn’t like about it:
– size
– completely superfluous external crystal (it’s not like we’re using the AVR osc for any vital timing, right?)
– not equipped to do much besides marking the passage of time
– not expandable in any way
– i’d get tired of the LED layout pretty quick and would want more
– no DS1337 alarm/interrupt support
– buttons on top instead of the sides
– size
– did i mention size?

So here (above) is what i came up. An extensible dwittwe Arduino platform that’s more watchy, less bulky, crammed with some sensor goodies and extensible.

Specs:
– Atmega 168 or 328
– internal OSC (up to 8 MHz)
– two right-angle push-buttons
– one programmable LED
– buzzer (speaker)
– DS1337 with a 32.768 kHz crystal for timekeeping
– BMP085 for pressure (baro) and temperature sensing
– microUSB for charging
– 4 headers for “Faces” – Chronoduino shields
– footprint: 1.52″ = 38.6mm diameter

MakerBot watch is thin, but has a huge footprint. This thing’s sized more like a regular watch (add a case and it’s still within 42ish mm dia, like most today’s watches), but thicker. It doesn’t come with any indicators whatsoever apart from a single LED. The idea being that you’ll add a shield (“face”, to keep things within the horological theme) on top of it with a UI of your choice + additional sensors. And if you want to, you can leave it bare and use it as, say, a really tiny sensor node.

I’ve also laid out an analogue LED face similar to MakerBot Watch’s, except this one also has a magnetometer on it (HMC5883) and two additional LEDs (for AM/PM indication). It’s called cFace because i was horribly unimaginative (“c” as in compass). Analogue LED compass. Yum yum!

Combined with Chronoduino, that makes for a fully functional alti-baro-temp watch, still within a watchy footprint, about 9mm thick, without the battery. And that’s solely because i didn’t find suitable low-profile board-to-board connectors yet and am planning on using regular 0.1″ headers on the prototype to keep things simple.

The headers on the Chronoduino are simple break-away pin headers. The receptacles on the cFace are SMD, because through-hole version would’ve interfered with the LED layout on the top. While we’re on the subject, best part is, the cFace and Chronoduino keep the same ATmega pinout as the MakerBot Watch, meaning any code written for MBW should work on the Chronoduino perfectly fine, without any changes.

So, there you have it. Coming up next – plans for future shields faces, face templates and updates on the component orders.

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8 Responses to “Behold! A Chronoduino!”

  1. J.B. Mannon 15/07/2011 at 18:59 #

    I’d love to see your design become reality. It got me thinking of a cube with six different, swapable faces.

    • orcinus 17/07/2011 at 02:28 #

      That would make one seriously insane (but awesome) Rubik’s Cube ;)

      • J.B. Mannon 17/07/2011 at 03:07 #

        Or one very crazy game of Pac-man! Add an accelerometer and you have hours of gaming goodness.

        • orcinus 17/07/2011 at 20:03 #

          Snake might be interesting too. Or Asteroids :o

  2. adnbr 19/07/2011 at 03:19 #

    Wow, that came about quick! I’m glad you explained how the faces are going to work,it makes much more sense to do it that way. The turning it into a datalogger/sensor idea is appealing as well.

    One quibble though – any chance of running the ground plane to the edges?

    • orcinus 19/07/2011 at 09:51 #

      Since the prototype PCBs have already been ordered, that will have to wait v0.2. Don’t like the slight Dharma Initiative tinge? :)

      • adnbr 19/07/2011 at 11:01 #

        Didn’t watch Lost, so most of such things will fly straight over my head!

        • orcinus 19/07/2011 at 22:08 #

          Was kinda sorta kidding :)
          The similarity wasn’t on purpose anyways. A friend commented the octagonal ground plane and the LEDs on the cFace reminded him of the DI logo.

          Not really sure why i’ve made it octagonal.

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