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I hope this leads to a phone / smart watch that lasts multiple days. Does anyone know how energy requirements break down between CPU and display in a typical de

I hope this leads to a phone / smart watch that lasts multiple days. Does anyone know how energy requirements break down between CPU and display in a typical device?

nosefurhairdo 3y ago
I've just shopped for a running watch, and while the AMOLED screen watches look nice, they claim to have ~50% the battery life in GPS mode compared to transflective LCD display watches. The article suggests a near-term 25% efficiency gain from this tech, so seems unlikely to translate to >2 day battery life.
- jeffbee 3y ago
  I have a Garmin with an OLED display and I usually have to charge it once a week or so. The GPS is by far the biggest power consumer. During activity tracking with the GPS turned on the battery lasts maybe 10 hours. It doesn't feel like a change in display technology would meaningfully change that situation.
  - xur17 3y ago
    Do you use it with the display always on, or do you have it wake up whenever you look at the display? I have a Garmin watch with a transreflective display, and end up charging it ~once a week with 1-2 hours of activity tracking per day.
  - FredPret 3y ago
    Why do these Garmins outlast Apple Watches by 5-10x? Is it because they're bigger? Or does the Apple Watch do more things?
  - londons_explore 3y ago
    > GPS is by far the biggest power consumer. There are some cool research papers about delayed processing of GPS data in the cloud. The idea is you turn the GPS on for just a few milliseconds, record the raw radio data (without getting a GPS location fix), and do that every 10 seconds or so. Then later you upload all the collected data to a big cloud compute cluster which can figure out all the locations (and where battery life doesn't matter). People are using that technique to have GPS trackers with years of battery life - handy for things like tracking animals.
    - xur17 3y ago
      Do you have any idea what the storage requirements are for a solution like this?
      - londons_explore 3y ago
        Pretty high - each location sample is hundreds of kilobytes if I remember correctly, although it was possible to trim that down if you knew there was a strong signal or you were happy to have some probability of an incorrect location. Annoyingly I can't seem to find the paper now.
    - ska 3y ago
      Tracking animals would seem to be a different set of requirements than, say, turn-by-turn car navigation. I'd imagine that for a lot of research, longer lifetime would win over real-time ish data, and possible you don't care so much about precision and granularity either. You probably want to upload semi often or risk losing the whole thing, but otherwise minimize batter use.
      - jeffbee 3y ago
        GPS already isn't good enough for car navigation, which also integrates wheel rotation and steering angle sensors. Even on a bicycle the tracking is noticeably better when you add a wheel rotation sensor to a GPS head unit.
        ska 3y ago
        Interesting! That doesn't really change the argument, does it? "Where am I right now", is a different requirement than "where have I been, roughly, over the last 6 mo"
        jeffbee 3y ago
        Yeah I was trying to agree.
jampekka 3y ago
There are smart watches that last multiple weeks, e.g. most Amazfit watches. The older models also used to have always-on transflective displays, which were vastly better to use a than the current OLEDs that need weird wrist gyrations to turn on.
J_Shelby_J 3y ago
Just disable the screen on an Apple Watch and it lasts for 2 and half days.
tetris11 3y ago
These have existed for decades. The problem is the ever demanding software filling up any of the hardware gains made in the last twenty years.
- eternityforest 3y ago
  Wearables are the one area where I'm really not happy with the efficiency of software. They don't really do anything that couldn't be done on early 2000s handhelds, why don't we have any kind of app-capable micro RTOS with an accompanying app store on Android for this stuff? An ESP32 and a microSD seems to be all any of it really needs.
  - tadfisher 3y ago
    This describes Pebble to a T. Customers bought the Apple Watch instead.
    - eternityforest 3y ago
      Pebble(Like Garmin which seems to be the modern equivalent, that I used to use before getting a Galaxy Watch) only had a tiny amount of flash storage and couldn't do maps or voice recording very well. The also used e-ink on one, which was probably slow, and it didn't have a touchscreen. It seems like they were explicitly trying to keep the features fairly simple, but they could probably do a lot more with similar battery life.
bityard 3y ago
I have a not-very-fancy Android smartphone that will easily go over a day between charges, if I let it. I can bump that up to 2.5 days between a full charge if I turn off Location and Bluetooth. (Which I usually do since I typically need neither.)

I hope this leads to a phone / smart watch that lasts multiple days. Does anyone know how energy requirements break down between CPU and display in a typical device?

nosefurhairdo 3y ago

I've just shopped for a running watch, and while the AMOLED screen watches look nice, they claim to have ~50% the battery life in GPS mode compared to transflective LCD display watches. The article suggests a near-term 25% efficiency gain from this tech, so seems unlikely to translate to >2 day battery life.

jeffbee 3y ago
I have a Garmin with an OLED display and I usually have to charge it once a week or so. The GPS is by far the biggest power consumer. During activity tracking with the GPS turned on the battery lasts maybe 10 hours. It doesn't feel like a change in display technology would meaningfully change that situation.
- xur17 3y ago
  Do you use it with the display always on, or do you have it wake up whenever you look at the display? I have a Garmin watch with a transreflective display, and end up charging it ~once a week with 1-2 hours of activity tracking per day.
- FredPret 3y ago
  Why do these Garmins outlast Apple Watches by 5-10x? Is it because they're bigger? Or does the Apple Watch do more things?
- londons_explore 3y ago
  > GPS is by far the biggest power consumer. There are some cool research papers about delayed processing of GPS data in the cloud. The idea is you turn the GPS on for just a few milliseconds, record the raw radio data (without getting a GPS location fix), and do that every 10 seconds or so. Then later you upload all the collected data to a big cloud compute cluster which can figure out all the locations (and where battery life doesn't matter). People are using that technique to have GPS trackers with years of battery life - handy for things like tracking animals.
  - xur17 3y ago
    Do you have any idea what the storage requirements are for a solution like this?
    - londons_explore 3y ago
      Pretty high - each location sample is hundreds of kilobytes if I remember correctly, although it was possible to trim that down if you knew there was a strong signal or you were happy to have some probability of an incorrect location. Annoyingly I can't seem to find the paper now.
  - ska 3y ago
    Tracking animals would seem to be a different set of requirements than, say, turn-by-turn car navigation. I'd imagine that for a lot of research, longer lifetime would win over real-time ish data, and possible you don't care so much about precision and granularity either. You probably want to upload semi often or risk losing the whole thing, but otherwise minimize batter use.
    - jeffbee 3y ago
      GPS already isn't good enough for car navigation, which also integrates wheel rotation and steering angle sensors. Even on a bicycle the tracking is noticeably better when you add a wheel rotation sensor to a GPS head unit.
      - ska 3y ago
        Interesting! That doesn't really change the argument, does it? "Where am I right now", is a different requirement than "where have I been, roughly, over the last 6 mo"
        jeffbee 3y ago
        Yeah I was trying to agree.

jampekka 3y ago

There are smart watches that last multiple weeks, e.g. most Amazfit watches. The older models also used to have always-on transflective displays, which were vastly better to use a than the current OLEDs that need weird wrist gyrations to turn on.

J_Shelby_J 3y ago

Just disable the screen on an Apple Watch and it lasts for 2 and half days.

tetris11 3y ago

These have existed for decades. The problem is the ever demanding software filling up any of the hardware gains made in the last twenty years.

eternityforest 3y ago
Wearables are the one area where I'm really not happy with the efficiency of software. They don't really do anything that couldn't be done on early 2000s handhelds, why don't we have any kind of app-capable micro RTOS with an accompanying app store on Android for this stuff? An ESP32 and a microSD seems to be all any of it really needs.
- tadfisher 3y ago
  This describes Pebble to a T. Customers bought the Apple Watch instead.
  - eternityforest 3y ago
    Pebble(Like Garmin which seems to be the modern equivalent, that I used to use before getting a Galaxy Watch) only had a tiny amount of flash storage and couldn't do maps or voice recording very well. The also used e-ink on one, which was probably slow, and it didn't have a touchscreen. It seems like they were explicitly trying to keep the features fairly simple, but they could probably do a lot more with similar battery life.

bityard 3y ago

I have a not-very-fancy Android smartphone that will easily go over a day between charges, if I let it. I can bump that up to 2.5 days between a full charge if I turn off Location and Bluetooth. (Which I usually do since I typically need neither.)