3 ms·

Speaking of which, how could mobile phones be made to work in extremely hot temperatures for emergencies without shutting down?

seventytwo 5y ago
It’s really just comes down to thermal mass vs. power dissipation. Either you have to increase the thermal mass, or limit the power. 99.99..% of use cases are for the phone to be in your pocket inside, so designing in a larger thermal mass, or limiting performance isn’t going to be a factor that drives design. However, since most phones are relative water resistant now, a good option is to use evaporative effects to cool them down. You could also dig a hole in the earth to find cooler temps and dissipate heat that way.
- failwhaleshark 5y ago
  I think the earth approach is a good option, even if one has to dig a few feet down to find some cooler ground in the middle of nowhere.
ajsnigrutin 5y ago
Mostly just by using better components and beter internal cooling (=thicker design). You can find same chips (=same function) made for consumer electronics, automative, aeronautic and military, all with different temperature and humidity ranges. I'm not sure about mobile phone CPUs/SoCs, but automotive equipment is a lot more resilient to voltage spikes well above the normal 12-14V.
- failwhaleshark 5y ago
  Aerospace / military spec'd components would probably be the best way to go where possible. If it's a lithium ion battery issue, then maybe they should be using a different battery chemistry.
alisonkisk 5y ago
Well you don't leave them out to bake all day, usually.
- wumpus 5y ago
  I left my Palm Pilot on the dashboard of my car one day, and the LCD melted. Fortunately, I had seen this before in undergraduate physics lab, the day our LCD experiment was interrupted by the room thermostat breaking, sending the temp > 100F. The nice thing about LCDs is that the crystals reform when it cools. All you have to do is wait. Probably works for most modern phone displays.

seventytwo 5y ago

It’s really just comes down to thermal mass vs. power dissipation. Either you have to increase the thermal mass, or limit the power. 99.99..% of use cases are for the phone to be in your pocket inside, so designing in a larger thermal mass, or limiting performance isn’t going to be a factor that drives design. However, since most phones are relative water resistant now, a good option is to use evaporative effects to cool them down. You could also dig a hole in the earth to find cooler temps and dissipate heat that way.

failwhaleshark 5y ago
I think the earth approach is a good option, even if one has to dig a few feet down to find some cooler ground in the middle of nowhere.

ajsnigrutin 5y ago

Mostly just by using better components and beter internal cooling (=thicker design). You can find same chips (=same function) made for consumer electronics, automative, aeronautic and military, all with different temperature and humidity ranges. I'm not sure about mobile phone CPUs/SoCs, but automotive equipment is a lot more resilient to voltage spikes well above the normal 12-14V.

failwhaleshark 5y ago
Aerospace / military spec'd components would probably be the best way to go where possible. If it's a lithium ion battery issue, then maybe they should be using a different battery chemistry.

alisonkisk 5y ago

Well you don't leave them out to bake all day, usually.

wumpus 5y ago
I left my Palm Pilot on the dashboard of my car one day, and the LCD melted. Fortunately, I had seen this before in undergraduate physics lab, the day our LCD experiment was interrupted by the room thermostat breaking, sending the temp > 100F. The nice thing about LCDs is that the crystals reform when it cools. All you have to do is wait. Probably works for most modern phone displays.