Arduino U8 Watch

Click on the Tab above to see the details of the watch including the Eagle layout files and the Arduino sketch.

Arduino on a U8 Smartwatch?

Hi guys,
In the continued effort to make the ultimate Arduino Smartwatch, I have created a drop in Arduino replacement board for the U8 watch. See the video. Also, visit my STEM education resource site at www.subsystems.us

See my latest video. Not much new, but the first time to see the completed prototype.

I will be creating a tab with all of the files required for this version of the watch. The two versions are:

v1: With thumb wheel and GY-80 IMU. (will not fit in iPod nano case, but you can use the backlight made for the display. Also no board mounted piezo speaker - but hookup pads available)

v2: With 3 micro pushbuttons and discrete chips for IMU and Pressure sensing and board mounted speaker. (will fit nano case)

Final Prototype (Yeah, right)

Here is the assembled watch in it's case.

Note, I changed the watch face from the previous prototypes. You know why? Because I can!! I love having a watch that is totally customizable.

This current version is different from the last because, instead of using an IMU board with the 3.3V power supply and the sensors, I have used discrete components. This has reduced the thickness to be able to mount the whole project in the iPod nano case. Well, almost. The battery is sitting on the outside of the case but adds so little to the width it is nearly undetectable. Here is the new assembled board:

The small square to the right of the ATMega1284p is the LSM9DS0 IMU chip and just to the right of that (the small silver looking square) is the BMP180 Pressure sensor. Note that I had to take part of the case off of the piezo speaker (large square on top of board) so that it would have the clearence needed to slide the case over it.

Here is the case going on:

Next, I position the battery and tape it down:

That is it. Place the band on and you are good to go.

Notice the profile. The battery is almost invisible.

That is it. You have an assembled watch. I will be posting a video soon. I have a couple of the blank pc boards for this project, so I may make them available to anyone looking to take on this project. All components come from Mouser and I will post the parts list when I post the updated schematic and layout files.

If you like this project, please like the post and share it with your friends. And don't forget to vote for it in the Atmel Simply AVR design contest!!! Thanks so much!!

I posted an updated video of the prototype watch. Go see it in action.

Final look

Here is a picture of what I am going for. This is my first prototype (with the sensor board removed) in the Apple Ipod Nano Aluminum Watch Band.

Really pretty. But here is the thing. It is tight in that case. The Ipod Nano 6th gen is tiny!!! I have the battery for it next to the watch in the picture and you can see that it takes up half the volume of the compartment. To make this all fit and still make it so it can be a hobbyist project may be a little much. The piezo speaker I got in from Mouser is only 3mm tall and is way too big for the housing. It will also be tough for the battery to slip in on top of components mounted on the board. I have a couple of options. I can make the watch a little thicker and stay with the rubber case which is pretty forgiving, I can strip the watch down a bit to fit in the nice rugged case, or I could try to fabricate a custom case for it. I am leaning toward the rugged case. I think the next watch will probably be a redesign using a Sharp Memory Display and a dedicated power management chip. I may also go with an ARM processor. I will update as this unfolds.

Battery voltage measurement

I have been thinking about the battery voltage measurement. There are many trade offs in the different methods to accomplish this. The voltage divider I have now works fine. In a voltage divider, the lower the resistance values, the better resolution you have, but the more current you draw. I use 100k ohm resistors so the total current draw (continuous draw) is 20 micro amps. This doesn't feel really good as the Atmel mega1284 can power down to about 1 microamp. The alternative is to add a switching circuit like a FET to switch on the power to the voltage divider. This would make the current draw almost zero when not in use, but adds to the complexity of the board layout. I think for the current version I am going to go with the simple voltage divider and suck up the current draw. After all, the lcd is drawing about 250 microamps anyway and my goal is really to stay below half a milliamp in idle mode. For later models I will consider some of the new battery monitors/manager chips out there. They are good at not only reporting voltage but tracking battery capacity to give you a better idea of remaining battery life. Parts arrived from mouser (particularly the small switches I need) so I will be finalizing the design of the next version. As much as I hate it, I will probably leave out the Bluetooth at this point because I really want this to fit in a good looking case. Stay tuned for updates.