I like a good smart watch and I appreciate open source, but an ESP32 isn't a great pick when low power consumption is important and the device is going to be communicating regularly. I'm surprised LILYGO went that direction in a watch form factor.
an esp32 on an 1100mah battery will last years on deep sleep, and about a day with wifi on and in high power modes.
a pixel watch 4 says they last 30 hours , ambiguously. they use a battery less than half the size. in reality with constant use they'll drop dead in 6 hours.
the thing is clunky and heavy , anyway -- so if it lasts as long as an off the shelf watch who cares?
also, the primary reason : lilygo shoves ESPs into everything.
Several Garmin watches last for weeks (24 days full charge, actual 1-2 weeks with heavy gps and fitness tracking), and I struggle to understand why consumers accept anything less. It seems like consumers don't realize what's available.
I think cost is one factor. I have a Vivoactive 4 and I love it but it has a reported battery life of 8 days and I get maybe half that with regular run tracking. I'm guessing the 24 days/1-2 weeks is for a considerably more expensive model.
The Garmin Instinct 2 is around $200 and will last several weeks on a charge even using the GPS regularly. Without GPS use I wouldn't be surprised if it lasted a month.
I'm not sure if my Pixel Watch 3 is much more efficient than your 4 or if by "constant use" you literally mean scrolling through it actively for hours at a time, but I only charge mine maybe twice a week. It's on at all times, connected to my phone via Bluetooth and to my Wi-Fi network when I'm home, and I actively manage any push notifications I get from it, but otherwise it seems to idle fairly efficiently.
I’ll need to check my notes on power consumption. I’ve spent quite a bit of time trying out different modes and configurations… it’s not great. I would not expect years at all. You gotta be very careful about what has to stay on and off.
Furthermore, bugs. To this time there’s random crashes that happen with sleep which limits their use
After careful optimization, the v1 got about 6 months out of a 1100 mAh battery. Later improvements and bumping to a 3300 mAh battery got me to 14 months, before my kid yanked it off the wall, total'd the panel and I rebuilt it. The test continues.
That said--op isn't wrong. If power usage is the metric you optimize for, there's much better BOM than an esp32.
Galaxy watch 7 (I think) weather here. Also about 30 hours. It's a charge every day thing, but allowing for some forgetfulness. It's not ideal, but it's manageable and certainly functional.
Yeah one of the Nordic nRF chips would be nice. But I guess the advantage of ESP is the hobby developer community. It's not going to be as good on battery power but the barrier to entry for people wanting to tinker is really low.
Nordic Semi, or maybe ST Micro. I've got an STM32WB on my bench at the moment with sensitive coulomb counting and it looks very promising but without all those radios. Of course with all those radios (ie, if you need LoRa on a watch... which is a design decision I'm also skeptical of) then Nordic has a good track record.
Different use case (environmental data recorder) but our current product uses an STM that turns on an ESP32 (not trusting that sleep mode) when it needs radio, to run on 2 AAs forever.
Hmm... I don't have an ESP32-S3 to test, but looking at one of the esp32s3 linux builds online[1], the binaries are compiled for the xtensa arch. So it does seem to run natively rather than through some kind of emulation. Linux's source does have an arch/xtensa/ directory, so that arch seems to be supported on some level by the kernel. ESP32-S3's docs also mention having an MMU[2], though it's possible it's not sufficiently featureful.
Interesting! I've only seen the older projects which probably predate the ESP32-S3. I wonder how usable this is in reality though because you typically can only buy modules with up to 8MB of PSRAM, so you'd have to swap the PSRAM out for higher capacity or manufacture a custom board.
