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How powerful of a computing device could be powered by a small solar panel these days? We had solar powered calculators in the 1980s, but with chips being so m

How powerful of a computing device could be powered by a small solar panel these days? We had solar powered calculators in the 1980s, but with chips being so much more energy efficient now, I imagine we could build a much more impressive device with no battery.

alar44 4y ago
Not really. To power an Arduino you need a much bigger solar panel than a calculator. Those calculators aren't necessarily inefficient, they just hardly do anything at all. You really can't do much more with a solar panel that size, it hardly captures any energy.
- Retric 4y ago
  Arduino’s are very power hungry compared to low power electronics. RFID tags for example are extremely low power. That said, there are solar powered scientific calculators which have dramatically more computing power and much larger displays than what people think of a solar calculators and still operate indoors at low light levels. Ex: TI-36X Pro A modern redesign could probably probably get ~1 GFLOPs, but those things are more designed for standardized tests than to be a useful tool.
  - akamaka 4y ago
    Thanks, this is a great data point. TI has some higher end calculators which are not solar powered, so that gives a good estimate of what was possible (at least when they last redesigned them).
- etrautmann 4y ago
  logitech used to get away with solar cells on the K750. It did sometimes die if left without much light but I was impressed it could operate as well as it did without direct sunlight.
  - akamaka 4y ago
    Thanks, this is a great example of what’s possible now, since it has wireless capabilities.
    - gambiting 4y ago
      We have them in all of our meeting rooms in our office, and they must charge enough just from the indoor lighting because they have been working for years without any battery changes(I don't think you even can change the battery in fact).
- iancmceachern 4y ago
  The Microchip brand micro in the arduino wouldn't be the right choice here. Something like the TI MSP430 would, it runs on very very low power requirements and has sleep functions that have insanely low power draw.
  - akamaka 4y ago
    This is exactly the answer I was looking for, thank you. This TI chip draws a little more power during computing than a calculator solar panel would provide, but it could easily work if it stayed in sleep mode part of the time.
chernofool 4y ago
You could probably get 2W from a wide over-ear band in direct sunlight. Maybe that's 2-4 hours per day, with indirect light scattered around the day. If you get say, 2W*6h=12Wh/day, you could afford about 15mA/hr @3.3V. That might be able to power a set of wireless headphones with a reasonably-sized battery, if you left them on a windowsill in direct sunlight when you weren't using them. Modern designs will probably use monocrystalline cells, but old solar-powered calculators used amorphous cells. Those are less efficient, but they can recover a trickle of energy from weaker light sources such as indoors or cloudy days. I also wonder what sort of materials they'll use. Plastics don't usually handle excessive UV exposure well.
- xani__ 4y ago
LeoPanthera 4y ago
Calculators are kind of a special case. When you are not pressing a button they are doing literally nothing, and maintaining the state of the LCD takes only microwatts. They use so little power that many "solar" calculators are fake, the "solar panel" is decorative only and a hidden button cell battery provides a decade of battery life: https://youtu.be/uLTDuGhqE2w https://youtu.be/uLTDuGhqE2w
- swagasaurus-rex 4y ago
  My childhood would have been so much more boring if I couldn't starve my calculator of light and watch the screen get dim
- astura 4y ago
  Is fake solar powered calculators a new thing or am I misremembering my childhood? I remember entertaining myself[1] by covering the solar cell and watching the screen go blank. Edit: nvm, YouTube comments and even a sibling comment to this mentioned the same thing, my childhood memories are real. After watching the YouTube video the guy took apart five calculators and only 2 had fake solar cells, so not what I expected. [1] yeah, pre Internet entertainment was boring in comparison.
reerdna 4y ago

alar44 4y ago

Not really. To power an Arduino you need a much bigger solar panel than a calculator. Those calculators aren't necessarily inefficient, they just hardly do anything at all. You really can't do much more with a solar panel that size, it hardly captures any energy.

Retric 4y ago
Arduino’s are very power hungry compared to low power electronics. RFID tags for example are extremely low power. That said, there are solar powered scientific calculators which have dramatically more computing power and much larger displays than what people think of a solar calculators and still operate indoors at low light levels. Ex: TI-36X Pro A modern redesign could probably probably get ~1 GFLOPs, but those things are more designed for standardized tests than to be a useful tool.
- akamaka 4y ago
  Thanks, this is a great data point. TI has some higher end calculators which are not solar powered, so that gives a good estimate of what was possible (at least when they last redesigned them).
etrautmann 4y ago
logitech used to get away with solar cells on the K750. It did sometimes die if left without much light but I was impressed it could operate as well as it did without direct sunlight.
- akamaka 4y ago
  Thanks, this is a great example of what’s possible now, since it has wireless capabilities.
  - gambiting 4y ago
    We have them in all of our meeting rooms in our office, and they must charge enough just from the indoor lighting because they have been working for years without any battery changes(I don't think you even can change the battery in fact).
iancmceachern 4y ago
The Microchip brand micro in the arduino wouldn't be the right choice here. Something like the TI MSP430 would, it runs on very very low power requirements and has sleep functions that have insanely low power draw.
- akamaka 4y ago
  This is exactly the answer I was looking for, thank you. This TI chip draws a little more power during computing than a calculator solar panel would provide, but it could easily work if it stayed in sleep mode part of the time.

chernofool 4y ago

You could probably get 2W from a wide over-ear band in direct sunlight. Maybe that's 2-4 hours per day, with indirect light scattered around the day. If you get say, 2W*6h=12Wh/day, you could afford about 15mA/hr @3.3V. That might be able to power a set of wireless headphones with a reasonably-sized battery, if you left them on a windowsill in direct sunlight when you weren't using them. Modern designs will probably use monocrystalline cells, but old solar-powered calculators used amorphous cells. Those are less efficient, but they can recover a trickle of energy from weaker light sources such as indoors or cloudy days. I also wonder what sort of materials they'll use. Plastics don't usually handle excessive UV exposure well.

xani__ 4y ago

LeoPanthera 4y ago

Calculators are kind of a special case. When you are not pressing a button they are doing literally nothing, and maintaining the state of the LCD takes only microwatts. They use so little power that many "solar" calculators are fake, the "solar panel" is decorative only and a hidden button cell battery provides a decade of battery life: https://youtu.be/uLTDuGhqE2w https://youtu.be/uLTDuGhqE2w

swagasaurus-rex 4y ago
My childhood would have been so much more boring if I couldn't starve my calculator of light and watch the screen get dim
astura 4y ago
Is fake solar powered calculators a new thing or am I misremembering my childhood? I remember entertaining myself[1] by covering the solar cell and watching the screen go blank. Edit: nvm, YouTube comments and even a sibling comment to this mentioned the same thing, my childhood memories are real. After watching the YouTube video the guy took apart five calculators and only 2 had fake solar cells, so not what I expected. [1] yeah, pre Internet entertainment was boring in comparison.

reerdna 4y ago