The year began and we were soon beset by more problems with pad placement. The bootloading pins on the board were placed very poorly and the ATMega328p was difficult to solder. Bootloading was also an unnecessary process that could be sidestepped by using a pre-bootloaded ATMega328p from a Arduino Pro Mini clone. The result: a second board as shown below.

Left is the poorly soldered board with bootloading pins, right is the thinner, sleeker board.

Unfortunately, the black board shown above was the incorrect size for the watch case. The board did not sit correctly on the lip of the watch case. We ordered new boards that were 0.5mm larger in diameter.

Meanwhile, I began working on and revising the CAD model of the watch case and I also began considering watch strap ideas. Below is the most recent model of the watch case, which has been 3D printed in my shop.

Notable features of this design include:

• A small lip to hold the circuit board
• About 7.1mm thick with an outer diameter of 40mm
• A small slot in the bottom of the case for a charging port

More about the charging port:

• It is a contact method that allows us charge while retaining water resistance
• This solution is cheaper than other water resistant methods, such as removable back and wireless charging
• We have made a charging interface for the port using pogo pins (shown below)Here is a picture of the charging interface on the case:
  You may be able to see a problem with the charging interface however. The pogo pins have a high chance of being being when placed on the watch case with this current design. The next design will include a snap-on mechanism to preserve the pogo pins.

Next time on the Arduino Neopixel Watch:

• Prototype Board Revision 3
• New Charging Interface
• Code Development

Maybe I will also come up with a cool name for the watch as well...

If you have any ideas or comments be sure to leave them on the project!