4 ms·

Most laptops and tablets run off of battery.

by Hydraulix989 9y ago

sova 9y ago
Yes, and most batteries require electricity. I'm glad you're in the discussion but you can do a lot better than that.
- wutbrodo 9y ago
  I assume that his point was that blackouts and brownouts have limited impact on battery powered devices vs devices plugged directly into the grid, since you can smooth over patchy electricity access by running on battery during blackouts and charging during availability periods. This is why a lot of places with unreliable infra use UPSs with their computers, but if course that means an even higher capital cost to get your system up and running.
- candiodari 9y ago
  You'd be surprised a) how common solar panels are (and how easy it is to partially repair broken solar panels) b) how simple they are to make if efficiency doesn't matter (optional glas + conductive grid + any black isolator + aluminum foil will result in power delivered between the grid and the aluminum. Paper (even white laser printer paper frankly) will do fine as isolator, also I heard balloon plastic works very well. Of course a transparent conductor works way better than a grid (which is where 80% of the efficiency comes from), but it works at like 5-10% efficiency with a grid) (the optional glass is to keep it clean, you can of course also just clean it regularly) c) how long batteries last if you only ever use 5% of their capability
  - sova 9y ago
    Sounds like he could be teaching his class how to make solar panels.
  - y4mi 9y ago
    > c) how long batteries last if you only ever use 5% of their capability not very long if they're alkaline. And its doubtful anything but their phones got li-on batteries in ghana, the markup probably isn't worth it. And there probably are hardly any phones. so mostly no li-on batteries anywhere. but i've never been there, just economically speaking.
    - Symbiote 9y ago
      I haven't been to Ghana, but I have been to Senegal, which is supposedly poorer. Maybe a third of the people had a smartphone, most people had a basic phone. The smartphones were $100 Chinese Android things. I felt perfectly safe wandering round with my 3 year old smartphone out, since I'd clearly taken less care of it than the average Senegalese would have.
  - daemoncoder 9y ago
    Do you have any references for (b)?
shakna 9y ago
This is actually a good point. A friend of mine is from Ghana, and wanted to be a programmer. He had to build a battery bank to power his laptop, so he could do his exams without issue. I helped him design the bank, and another little tool we found helpful. Because power is such an issue, we used a couple Arduinos to build something reminiscent of the TRS-80, 200 [0]. Instead of BASIC though, we inbuilt a C-repl, based around Cling [1], though much less featured. It ran off 4 AA batteries, and lasted about six hours between charges, which though kinda crap, was enough that his power bank was always ready to recharge it, and he could keep going. It was all his idea, I just served as the technical expert. I believe he's currently building and selling a few of these out of his house since he went back to Ghana, to help people get a hang of computing. [0] http://oldcomputers.net/trs200.html http://oldcomputers.net/trs200.html [1] https://root.cern.ch/cling https://root.cern.ch/cling
- Hydraulix989 9y ago
  So you also built a low power computer much like the kits in the 80s? That's really cool! Why use C as a starting language?
  - shakna 9y ago
    Because his exam was in C, basically. He was doing remote study with an Australian course, which required it. For the Python parts he still had to use his normal laptop, because MicroPython wasn't around then, (and I took a look at porting CPython to an AVR and immediately gave up), and he hated it. Constant power glitches caused the laptop to misbehave. His BW-1 (Borkwei-1), and it's tiny portable power, meant he got a lot more done. If I was to redo it today, because it was about 6 years ago now, I'd probably make one with either MicroPython or eLua. Basically hook a keyboard and screen up to a NodeMCU or MicroPython board (maybe an ESP32), because those sort just about everything out nowadays. (MicroPython even comes with a FAT filesystem. Add a board with WiFi, and you have a very decent system.) He tells me that every house in his village has one of the little laptops we designed now, though he has upgraded it to use an SD card, so more programs, and WiFi for when they hit town. He now calls it the BW-2.
- 9y ago

Most laptops and tablets run off of battery.

sova 9y ago

Yes, and most batteries require electricity. I'm glad you're in the discussion but you can do a lot better than that.

wutbrodo 9y ago
I assume that his point was that blackouts and brownouts have limited impact on battery powered devices vs devices plugged directly into the grid, since you can smooth over patchy electricity access by running on battery during blackouts and charging during availability periods. This is why a lot of places with unreliable infra use UPSs with their computers, but if course that means an even higher capital cost to get your system up and running.
candiodari 9y ago
You'd be surprised a) how common solar panels are (and how easy it is to partially repair broken solar panels) b) how simple they are to make if efficiency doesn't matter (optional glas + conductive grid + any black isolator + aluminum foil will result in power delivered between the grid and the aluminum. Paper (even white laser printer paper frankly) will do fine as isolator, also I heard balloon plastic works very well. Of course a transparent conductor works way better than a grid (which is where 80% of the efficiency comes from), but it works at like 5-10% efficiency with a grid) (the optional glass is to keep it clean, you can of course also just clean it regularly) c) how long batteries last if you only ever use 5% of their capability
- sova 9y ago
  Sounds like he could be teaching his class how to make solar panels.
- y4mi 9y ago
  > c) how long batteries last if you only ever use 5% of their capability not very long if they're alkaline. And its doubtful anything but their phones got li-on batteries in ghana, the markup probably isn't worth it. And there probably are hardly any phones. so mostly no li-on batteries anywhere. but i've never been there, just economically speaking.
  - Symbiote 9y ago
    I haven't been to Ghana, but I have been to Senegal, which is supposedly poorer. Maybe a third of the people had a smartphone, most people had a basic phone. The smartphones were $100 Chinese Android things. I felt perfectly safe wandering round with my 3 year old smartphone out, since I'd clearly taken less care of it than the average Senegalese would have.
- daemoncoder 9y ago
  Do you have any references for (b)?

shakna 9y ago

This is actually a good point. A friend of mine is from Ghana, and wanted to be a programmer. He had to build a battery bank to power his laptop, so he could do his exams without issue. I helped him design the bank, and another little tool we found helpful. Because power is such an issue, we used a couple Arduinos to build something reminiscent of the TRS-80, 200 [0]. Instead of BASIC though, we inbuilt a C-repl, based around Cling [1], though much less featured. It ran off 4 AA batteries, and lasted about six hours between charges, which though kinda crap, was enough that his power bank was always ready to recharge it, and he could keep going. It was all his idea, I just served as the technical expert. I believe he's currently building and selling a few of these out of his house since he went back to Ghana, to help people get a hang of computing. [0] http://oldcomputers.net/trs200.html http://oldcomputers.net/trs200.html [1] https://root.cern.ch/cling https://root.cern.ch/cling

Hydraulix989 9y ago
So you also built a low power computer much like the kits in the 80s? That's really cool! Why use C as a starting language?
- shakna 9y ago
  Because his exam was in C, basically. He was doing remote study with an Australian course, which required it. For the Python parts he still had to use his normal laptop, because MicroPython wasn't around then, (and I took a look at porting CPython to an AVR and immediately gave up), and he hated it. Constant power glitches caused the laptop to misbehave. His BW-1 (Borkwei-1), and it's tiny portable power, meant he got a lot more done. If I was to redo it today, because it was about 6 years ago now, I'd probably make one with either MicroPython or eLua. Basically hook a keyboard and screen up to a NodeMCU or MicroPython board (maybe an ESP32), because those sort just about everything out nowadays. (MicroPython even comes with a FAT filesystem. Add a board with WiFi, and you have a very decent system.) He tells me that every house in his village has one of the little laptops we designed now, though he has upgraded it to use an SD card, so more programs, and WiFi for when they hit town. He now calls it the BW-2.
9y ago