Timex R300 charger

After the gnarly 4 hour recording, it recorded for 5h40m with 59% still left in the tank.  The option to disable heart rate detection didn't do anything.  It still continuously flashed the heart rate LEDs & recorded heart rate.  The only other changes were disabling the backlight, disabling the touch screen & not wearing it. It was still in airplane + do not disturb.  It seems the backlight runs constantly if it's enabled.

It'll never go 20 hours because the heart rate sensing can't be disabled.  Heart rate sensing might have either once been optional in another android version or it might have always been mandatory during workouts.  The app has so many bugs, it's not surprising that some options don't work.  The app needs to be restarted after syncing.  It somehow reported 177 bpm without being worn, but it didn't report any steps.

Never used it except those last 2 workouts.  It's the 1st fancy watch lions have had in 40 years.  The last one was a short lived, $80 Casio databank which captivated young lion.  The GPS watch has a vastly more capable screen & a similar array of bling for less money, but it just doesn't get lions excited beyond its intended purpose of recording 1 marathon.

Maybe it was just a bigger leap 40 years ago.  Maybe the idea of the incandescent backlight running off a watch battery & miniature keyboard were more intriguing.  Anything that small, animating a display on its own was fascinating even if it was just seconds.  Getting old makes animals more excited about a frying pan than a fancy watch & there's no going back.  The world is like the same food we've been eating for 50 years.

The pogo pins from the mismatched chargers did well enough to try building another mag charger out of them.  It was just a lot of hot snot on a panel.  There was just a right amount of protrusion to keep the pogo pins from lifting the magnets off while still conducting.  This could be fudged & then the hot snot slathered on to keep it in place.

It self aligns better than the clamp design & is reliable enough to not require any fuss.  It would be a more compact solution for traveling, but it could also give up the ghost in transit.  While the magnets are not as secure as the clamp, it's not going to slip off the contacts like the clamp.

Ran for 4 hours with it in airplane mode & heart rate detection on, which left it at 22%.  It's nowhere near the 20 hours of a new battery.  It's not likely to last through a lion marathon.  The only way to replace the battery would be to release the screen adhesive.   It would also be nice to get rid of the magnets to make  it lighter.  Making it lighter trumps any benefit to the magnetic charger.

There is another option to disable heart rate detection.

As usual, there might be 1 guy who exists purely online, who got a working GPS watch for $60 + tax.  The $60 GPS watch is too good to be true for the rest of us.  They're all returns that others bought just to swipe the charger & returned with a wrong but retail charger.  There is no retail charger for the $60 GPS watch.

Fortunately, we can attempt to make the $60 GPS watch a reality by fabricating a custom charger.  It's just 2 pogo pins held on by 6x3mm magnets.  3D printing it is no problem, but getting good contact is.  These particular pogo pins were particularly finicky.  A better contact would be a solid gold pad.  It draws 40-130mA at 5V.  A few attempts with a magnetic carrier were failures.  The magnets couldn't provide enough force to get the pogo pins to compress so the assembly just stood above the  watch.  It needed a lot of fidgeting & was unreliable.

It's hard to believe anyone had a pleasant experience with contacting chargers. 

Printing the alignment fiducial & magnet holders is difficult.  The magnets alone seem to get it close enough.

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A few failures with magnets gave way to a side clamp.  The pogo pins couldn't retract enough to get it on the watch.

A full sized charging clamp showed more promise but was hard to align.

The incompatible chargers had scavengable pogo pins.

These pogo pins were solid.  The only time it absolutely wouldn't connect was a USB charger which made 4.5V.  Giving it slightly over 5 seemed to help it. 

Lions wouldn't bother with the magnetic system, even with solid pogo pins.  Only the full clamp is going to guarantee a charge when it's essential, the night before the race.  In what lions managed to get working, it doesn't seem to take any input when it's charging, so there's no need to have the screen exposed.  During other tests, it briefly showed a charging icon in the interactive screen, as if there was another mode where it could take input while charging.

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Also noted this watch requires the Timex Smart app which was dropped from Goog long ago.  The only way to get data off of it now is to download an APK & click through a bunch of confirmations.

https://apkpure.com/timex-smart/com.timex.app.android

Forced obsolescence & pricing is real severe with watches because they can't monetize the screen like a phone.  You have to do a factory reset on the watch before it can pair.  It automatically syncs with the watch. Recorded workouts can be sent to goog drive as GPX files.  All lions need is GPS recording.

25 years ago, an army of college students would have reverse engineered every watch protocol & made a gphoto, cdparanoia, or decss for watches.  The industry has changed from doers to spectators.

The screen is surprisingly bright, compared to lion memory of past transflective displays.  The last transflective display a lion saw was a powerbook in 1994.  It was only legible in direct sunlight.

Based on the battery life, it might be a really old one that someone eventually lost the charger for, then swapped with a new one to get a new charger & returned with a wrong charger.