So after making the first usable prototype of the swim watch, I wanted to try it out in the pool to see how it worked and any initial issues I could find.
To try and make the device waterproof, I wrapped it and the battery in cling-film and then placed it in a water-proof bag designed for taking keys when I go open-water swimming. The bag comes with a strap to hold it against your arm. The photo below shows the watch strapped to my hand before I set off swimming.
As you can see it was rather large…
However, it stayed in place well enough, and didn’t cause too much disturbance to my swimming, apart from it flapping about a little bit to start with.
A few things to note:
- The OLED display was very east to see under the water, but it would have been better if certain texts were bigger.
- Pressing the button while the watch is on the wrist wasn’t great. What I would do is press the button as I was pushing off, but that meant that my hands weren’t in their normal place (straight out in front of me).
- The button size was OK, but it would have been better if it was bigger.
- For quickly checking the number of laps, the OLED display is more than big enough.
- Some kind of buzzer / vibrator is needed to acknowledge a button press.
- There needs to be a power-off button (probably easier to waterproof than a switch.
In general, it seemed to work quite well, but for some reason, at 20 lengths the watch crashed and I couldn’t get it to work at all. The display was stuck on 20 lengths. So I just left it as it was and carried on using my Garmin to “estimate” the number of lengths I’ve swam.
After taking the watch home and taking the battery out and then back in, the device wouldn’t switch on. I then tried connecting it up to me RaspPi and it couldn’t find the processor.
After a while of trying and failing to find the fault, I decided to stop wasting my time and assume that the chip broke due to moisture getting into it. However, to try and replace the uC would take too long and probably destroy the copper tracts so I’ve decided to call this a partial success and move onto the next stage. In all the tests I did outside the pool, the watch never stalled, so I’m just going to presume it’s something to do with water getting into it somewhere.
For the next version of the swim watch, I intend to work on the following:
- Create a PCB version of the device using SMD components to make the device as small as possible.
- Create the first proto-type to fit on the finger
- Have 4 buttons: up, down, select / count length, and power / back
- Choose a button for “select” that’s longer, so easier to press when on the button
- Find a way to waterproof the whole thing
- Find a small battery and create a charging circuit for it
- Improve the user interface and possibly allow for some user-defined interfaces.