Monday, June 23, 2014

DIY Smartwatch: Improvements for V2

From the current progress I've already made on this project, I can already see a lot of mistakes and things that will need to be improved for the second PCB.  Below is a list of the ones that immediately come to mind.
  • Possibly use the onboard voltage regulator on the Adafruit display
    • The Adafruit display board already has a 3.3V regulator for the screen logic, using this would mean one less part that I need and would give me a tiny bit extra space.
  • Maybe just switch to the E-Ink display to save power
    • I was very dismayed by the enormous amount of power the screen uses.  Even if I get tricky and heavily optimize the screen usage, I'm not sure how long I can get the battery to last.  This is a last ditch solution and would probably involve an entire re-layout of the board.
  • Use through holes for the battery instead of a connector
    • The battery connector is the tallest component on the board aside from the connectors, getting rid of it would mean I can make the uber-thick watch a little bit thinner.  Since I have verified that the battery charging circuit works, I just need to decide which battery will be used I should then be able to solder it in permanently.
  • Use micro USB instead of mini
    • Same thing as above, the mini USB is pretty tall.  A micro USB connector didn't seem much harder to solder and would give me a little extra space.
  • Get rid of reset button
    • When I'm entirely done programming the watch, I'll most likely give it a simple case, making the Reset button entirely inaccessible anyway.  It might be better for space to replace the button with a test point.
  • Add real-time clock
    • With the added space from removing components, there might be room for an RTC that could be used to keep better track of time.
  • Enlarge accelerometer pads for easier soldering
    • As previously stated, the accelerometer is very difficult to solder, especially without a hot air station.  If I don't decide to buy one, another option might be to enlarge the pads for the accelerometer chip connections so it is easier to touch with the soldering iron.
  • Move tall components away from microSD slot on display board
    • In line with the USB and battery connections, I need to plan ahead so that the top boards fits better with the bottom board with less wasted space.
  • Silk screen labels
    • Since I rushed to ship out the board for fab, I didn't take the time to properly and clearly label all the components on the board.  Doing so would make identifying what needs to go where much easier and would make debugging simpler if I know what vias are attached to what.
  • Test points
    • It would probably help to have some dedicated test points to make sure the circuit is behaving as it should be.

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