4 ms·

First off - this thing was designed to be a fun hacker toy, not a real product. Buyer beware! Plan for power management is pretty simple - trim as much fat fro

First off - this thing was designed to be a fun hacker toy, not a real product. Buyer beware! Plan for power management is pretty simple - trim as much fat from OS startup sequence as possible to get boot-times down to ~5s, eg https://github.com/IronOxidizer/instant-pi https://github.com/IronOxidizer/instant-pi. Then turn the Pi off as much as possible. Write to screen, turn off Pi. Set timers on rp2040 to turn Pi on periodically. With the 2000mAh battery, if the plan works, it should run for a while.

kragen 3y ago
does that mean that every time you hit a key (after the idle timeout) you have to wait 5 seconds for the pi to boot, wasting 5 more precious joules (a minute of active usage battery life at 100mW) or does the pi zero have a submilliwatt suspend to ram and i'm just the last to know i think that it could be a fun hacker toy if you put a low-power microcontroller on it with access to the screen and keyboard and control over the pi's power rails (and the rp2040's if you put that in too) as a bonus if the low-power micro was an esp32 you would have wifi and bluetooth then you only need to fire up the pi when its computational gronk is really needed, and the ui stays responsive the whole time 2 amp hours (why would you say 'two thousand milliamp hours', that's four extra syllables for no reason) is 27 kilojoules at 3.7 volts; that's ten months at one milliwatt, a weekend at an esp32-like 100 milliwatts, 7 hours at an optimistic one watt, or three hours at 2.5 watts, which i think is more realistic for the pi you won't even be able to use this thing all night with the pi running; you'll need an external battery to recharge it before the sun comes back up, like that old laptop that you used to take out of the house back when its battery lasted more than two hours also 2 amp hours is somewhere in the neighborhood of 20 grams of battery, while the rest of the device is i think around 15 grams. admittedly still pretty small and light compared to the fragile monsters that pass for android cellphones nowadays
- erohead 3y ago
  > does that mean that every time you hit a key (after the idle timeout) you have to wait 5 seconds for the pi to boot, wasting 5 more precious joules (a minute of active usage battery life at 100mW) Yes, that's exactly the plan. Pi zero does not have suspend to ram unfortunately, hence this elaborate work around. Remember, the use case is a weekend chat device. This power management scheme fits the use case perfectly.
  - kragen 3y ago
    well, i agree that your chat message being delayed for 5 seconds is not critical but waiting 5 seconds for a keystroke to be echoed (sometimes) is appalling. you would not get permission to do a user study from an irb. it would be denied on grounds of needless cruelty to experimental subjects it would fit the use case perfectly if you had a low-power microcontroller that updated the screen in response to keystrokes, but what you're describing is a user interface design botched for no good reason even the rp2040 would work for that at the weekend level this is not quite a 'solar freakin' roadways' level of mistake because you could fix it with relatively minor tweaks to the design, but if you don't, you'll be left with a design that's unusable on battery, either because of battery life or responsiveness fwiw i don't think restarting a computer in response to a keystroke is an elaborate workaround at all; that part of the design is perfectly reasonable check out how mosh predicts keystroke effects for 'speculative local echo' and think about how you could do that on the rp2040 (or ideally an esp32 or apollo3 or something) while you're waiting on the giant linux behemoth to awaken from its slumber and restart gomuks or vim or whatever
    - erohead 3y ago
      I think you are misunderstanding the plan. The device will stay on until you turn it off, or 5 mins after last keystroke.
      - kragen 3y ago
        you say 'I think you are misunderstanding the plan. The device will stay on until you turn it off, or 5 mins after last keystroke.' that's the plan i described yesterday in https://news.ycombinator.com/item?id=35983387 https://news.ycombinator.com/item?id=35983387 that's the plan i think will give you three hours of battery life: 2 amp hours times 3.7 volts divided by 2.5 watts gives 3 hours of use. 36 5-minute timeouts. do you have a different estimate? did i miscalculate? that's not a weekend in that comment i also explained an approach that would beat that by two orders of magnitude if you applied it with the same components (though there i supposed the hardware would use an esp32) btw my grandparent comment https://news.ycombinator.com/item?id=35984332 https://news.ycombinator.com/item?id=35984332 is upvoted to 11 at the moment so evidently even if you think it's stupid your customers don't
- msephton 3y ago
  You've just described a Playdate. It's a game console not a computer but it pretty much is designed how you've suggested. It also uses the same Sharp Memory LCD.
  - kragen 3y ago
    it's the sensible way to design a system around this display, but the playdate isn't what i'm looking for because it doesn't have a keyboard and also it's kind of bulky
- OOPMan 3y ago
  I'll have you know my fragile monster of a razer phone 2 has survived being dropped more often than I can count XD
  - kragen 3y ago
    the razer was way lighter and less glass-intensive than currently popular phones but what's a razer 2
paulcole 3y ago
Bro, if you’re taking real money it’s a real product. Put that caveat somewhere obvious on the site. “I’m not taking this seriously but I will seriously take your money! Caveat emptor!”
- xupybd 3y ago
  It's a kitset, not a finished end user product.
- BizarreByte 3y ago
  The website shows it with a battery being held on with a rubber band. If you're buying this you should know what you're getting from just a quick look.

kragen 3y ago

does that mean that every time you hit a key (after the idle timeout) you have to wait 5 seconds for the pi to boot, wasting 5 more precious joules (a minute of active usage battery life at 100mW) or does the pi zero have a submilliwatt suspend to ram and i'm just the last to know i think that it could be a fun hacker toy if you put a low-power microcontroller on it with access to the screen and keyboard and control over the pi's power rails (and the rp2040's if you put that in too) as a bonus if the low-power micro was an esp32 you would have wifi and bluetooth then you only need to fire up the pi when its computational gronk is really needed, and the ui stays responsive the whole time 2 amp hours (why would you say 'two thousand milliamp hours', that's four extra syllables for no reason) is 27 kilojoules at 3.7 volts; that's ten months at one milliwatt, a weekend at an esp32-like 100 milliwatts, 7 hours at an optimistic one watt, or three hours at 2.5 watts, which i think is more realistic for the pi you won't even be able to use this thing all night with the pi running; you'll need an external battery to recharge it before the sun comes back up, like that old laptop that you used to take out of the house back when its battery lasted more than two hours also 2 amp hours is somewhere in the neighborhood of 20 grams of battery, while the rest of the device is i think around 15 grams. admittedly still pretty small and light compared to the fragile monsters that pass for android cellphones nowadays

erohead 3y ago
> does that mean that every time you hit a key (after the idle timeout) you have to wait 5 seconds for the pi to boot, wasting 5 more precious joules (a minute of active usage battery life at 100mW) Yes, that's exactly the plan. Pi zero does not have suspend to ram unfortunately, hence this elaborate work around. Remember, the use case is a weekend chat device. This power management scheme fits the use case perfectly.
- kragen 3y ago
  well, i agree that your chat message being delayed for 5 seconds is not critical but waiting 5 seconds for a keystroke to be echoed (sometimes) is appalling. you would not get permission to do a user study from an irb. it would be denied on grounds of needless cruelty to experimental subjects it would fit the use case perfectly if you had a low-power microcontroller that updated the screen in response to keystrokes, but what you're describing is a user interface design botched for no good reason even the rp2040 would work for that at the weekend level this is not quite a 'solar freakin' roadways' level of mistake because you could fix it with relatively minor tweaks to the design, but if you don't, you'll be left with a design that's unusable on battery, either because of battery life or responsiveness fwiw i don't think restarting a computer in response to a keystroke is an elaborate workaround at all; that part of the design is perfectly reasonable check out how mosh predicts keystroke effects for 'speculative local echo' and think about how you could do that on the rp2040 (or ideally an esp32 or apollo3 or something) while you're waiting on the giant linux behemoth to awaken from its slumber and restart gomuks or vim or whatever
  - erohead 3y ago
    I think you are misunderstanding the plan. The device will stay on until you turn it off, or 5 mins after last keystroke.
    - kragen 3y ago
      you say 'I think you are misunderstanding the plan. The device will stay on until you turn it off, or 5 mins after last keystroke.' that's the plan i described yesterday in https://news.ycombinator.com/item?id=35983387 https://news.ycombinator.com/item?id=35983387 that's the plan i think will give you three hours of battery life: 2 amp hours times 3.7 volts divided by 2.5 watts gives 3 hours of use. 36 5-minute timeouts. do you have a different estimate? did i miscalculate? that's not a weekend in that comment i also explained an approach that would beat that by two orders of magnitude if you applied it with the same components (though there i supposed the hardware would use an esp32) btw my grandparent comment https://news.ycombinator.com/item?id=35984332 https://news.ycombinator.com/item?id=35984332 is upvoted to 11 at the moment so evidently even if you think it's stupid your customers don't
msephton 3y ago
You've just described a Playdate. It's a game console not a computer but it pretty much is designed how you've suggested. It also uses the same Sharp Memory LCD.
- kragen 3y ago
  it's the sensible way to design a system around this display, but the playdate isn't what i'm looking for because it doesn't have a keyboard and also it's kind of bulky
OOPMan 3y ago
I'll have you know my fragile monster of a razer phone 2 has survived being dropped more often than I can count XD
- kragen 3y ago
  the razer was way lighter and less glass-intensive than currently popular phones but what's a razer 2

paulcole 3y ago

Bro, if you’re taking real money it’s a real product. Put that caveat somewhere obvious on the site. “I’m not taking this seriously but I will seriously take your money! Caveat emptor!”

xupybd 3y ago
It's a kitset, not a finished end user product.
BizarreByte 3y ago
The website shows it with a battery being held on with a rubber band. If you're buying this you should know what you're getting from just a quick look.