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snvzz

Very cool project overall. The only nag being

>Sensor Watch sips single-digit microamperes of power, making this a watch you can wear all year on a single coin cell.

That's a downgrade vs original board.

None of the alternative PCBs, clones and such I have seen so far manage to even match the original.

Is getting into the nanoampere territory really that hard to achieve, with technology that's some 30+ years newer?

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You are comparing a very purpose-built chip in the original watch to a general purpose microprocessor in this design. The original won't have a single extra transistor than it needs, and it won't be operating one Hz faster than it needs to. Not a surprise to me.

And in reality, the real-life battery life of the Sensor Watch will drop further if you actually attach actual sensors to it or (I'd expect) start running your own code on it.

The Movement framework for developing watch faces tries to steer folks toward low power consumption by default; the watch spends most of its time in standby, and a custom watch face only runs code once per loop (which is once a second by default, although you can request more frequent updates from 1 to 128 Hz). This means most watch faces can actually stay under 10 µA as long as they don't need to update too frequently; up to about 16 Hz, power consumption remains decent.

Anecdotally, my daily driver is coming up on 550 days on the same CR2016 coin cell from February 2022, and I think it's on track to make it to 2024. A far cry from the original's 7+ year battery life, but still pretty good considering all it's capable of!

That is really impressive!!! Are you able to do some kind of power management on any attachable sensors as well besides whatever their standby current is?

This board is an order of magnitude more capable as a general CPU than the original, that's why it takes more power. The SAM L22 processor on it has 32 kilobytes of RAM and 256 kilobytes of code/flash storage vs basically zero memory or programmability on the original. You could easily run micropython, tinygo, johnny five (JavaScript), lua or other high level languages directly on the L22 processor here. It's a fun board for embedded electronics hobbyists. If you've ever played with an Arduino, this is basically one you can wear on your wrist in a classic watch shell.

I don't think this product is for you if you're just expecting a longer battery life watch... and that's ok!

>> Sensor Watch sips single-digit microamperes of power, making this a watch you can wear all year on a single coin cell.

> That's a downgrade vs original board.

> None of the alternative PCBs, clones and such I have seen so far manage to even match the original.

Yeah, but it's still extremely impressive given the upgrade in capability. I'm sure a designer has to make major compromises to optimize for battery life to level of the original.

Though, for something like this, it might have made more sense to target something like the Casio W800H-1AV; which is another cheap classic Casio, but it has a bigger battery, more display capability, and a 4th button.

My first thought as well. I have worn this watch every day since 2009. Last year I changed the battery for the first time. I have always thought that it is the perfect form factor to fit some more fancy stuff in there.

In an update on crowd supply, the creator mentioned he got 425 days of battery life, which I feel like is pretty good considering how powerful the CPU is compared to the original!

https://www.crowdsupply.com/oddly-specific-objects/sensor-wa...

I'm not sure that it'd be easy to get that -and- programmability, and past about the 6 month per battery swap mark I'd likely rather have more CPU/RAM/flash than more battery life.

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