Arduino Neopixel Watch

After reaching out to others who have made similar neopixels watches asking if they would like to help inorder to be able to, add additional functionality, such as bluetooth and app support. With additional team members working on different aspects of the watch.

Austin Nelson - App developer

Leon Gaulin - Arduino programmer

and others.

Blue tooth adds a nice GUI as opossed to different tap detection modes, as well as Notifications and tactile feed back for alerts.

Demo of bluetooth app found here https://hackaday.io/project/20693-flora-ble-smartwatch

After reflowing the board, after some testing it dose not connect to the computer, I think it is due to cooling it down to quickly as I recall hearing some cracking noises when it was cooling down. believing this was the problem I soldered up another board, taking care not to let it cool down to quickly.

As i go and hook it up to the computer realizing I let my friend barrow my programmer over the week end I try to use a cheap one i had laying around but upon testing the programmer on a known to work arduino pro mini the programmer dose not not work. So I ordered a new one, came in a few days later. I hook up the new board and it dose not work!

So I test the neopixles by hooking up some test pins to the signal in on the neopixles from another arduino, they work fine.

hook up a arduino to the i2c line and it dose not work, could possible be the light sensor because it is square and the pin 1 marking is really hard to see so I could have gotten it backwords, going to desolder it and test the I2c lines again.

After several weeks of waiting the boards come in just as I finish up the case a day before. The stencil was cut on a laser cutter but the settings were off and I didn't have time to make new ones so the stencil only was able to apply solder paste to the bigger pads so I added solder to the smaller capacitors and resistors with a needle.

Watch case fresh out of the mill, ready to be broken out of the extra bits holding it onto the stock. After inspecting the inside it seems to be perfect fit for the battery, will be able to do a test fit of the circuit boards ones they come in.

The charging connector also acts as a programming cable for the Atmega328p. To save on space the battery charging circuit is externalized, using the pogo pins and concave pins on the back of the watch, has all the nessesary pins to be able to charge and reprogram the Atmega. Using a standard battery charger and a FTDI brake out connected to the pogo pins.

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!

After learning how to use eagle and making a schematic and board layout was designed the boards were ordered.

Parts were purchased, mainly from Digikey, and were cheap and quickly shipped. Unfortunately, upon getting the boards weeks later, a mistake was made the on the pad layout of the real time clock, so in order to be able to test the circuit desperate things were done... We had to bend the leads of a DIP RTC in order to fit the misaligned pads, same with one of the resistors as well.

Despite these challenged, we persevered and became closer to our goal!

The project was shelved for a few months, due to not knowing how to continue and improve on the design in a way that could be accomplished at the time, mostly due to budget constraints and not having access to a 3D printer over the summer.

During this time, several methods of an easy to implement an input method were brainstormed:

• Button - would be too difficult to waterproof without a custom cap
• Encoder - (like apple watch) cool idea but hard to fit into a watch with standard components
• Accelerometer - (tap detection + gestures) easy to waterproof and implement into the watch

After seeing a few other watches with an accelerometer as input I got the idea to use one, as it solves all the problems of being difficult to mechanically implement while being robust and water proof.

Spring 2015

• Purchased Neopixel ring, not really knowing what to use it for yet

Fall 2015

• Began generating concepts revolving around a watch-based project

1. Use LED ring as digital display
2. Use Arduino Pro Mini to control Neopixel ring

• Identified problems with current watch and smartwatch designs

1. Short battery life
2. Inaccurate time calibration
3. Fragile hardware
4. Bulky design