24 Responses

1. why not make solar cells like human eyes then? with big dynamic range?

2. Just connect the solar cell directly to the LED, do no use any resistor.

   3mA and 2V should be enough to see a little light coming from the LED.

3. Oh OK!

   Maybe you could someday run a video blog about these super capacitors (1Farad and beyond), their features and tradeoffs.

   They could be useful for ultra low power applications I think.

4. there are even 50F capacitors from goldcap… with a few volts…

5. ixys rules. you make good videos!

   the best solar calculator out there today is the casio fx-115ms. read the manual back to front and rejoice! you don’t need a matrix display for a good calculator, this one does everything an engineer would ever want.

6. You can’t. Those solar pannels are about 2 volts and only a few milliamps

7. great video

8. loar = solar soz

9. please can sum 1 tell me how to power a small led with a calculator loar cell please( thz im only 13)

10. Yes, that’s possible, but then it’s not a practical product. What happens when it’s FLAT and you want to use it right away? Calculators are only useful when they are instantly available, and no one wants yet another device they have to remember to charge.

11. Hi Dave, this is an idea… you can still use the solar cells and add a huge capacitor to store energy.

    Just use the same cells and charge the capacitor with direct Sun light outside.

    You can get a 1 Farad capacitor from some web sites. Yes, there are 1F capacitors :D

12. Since the surface of the watch is a PCB if you are willing to re design the PCB bit you can solder the Solar cells around the perimeter.

13. I understand the lumen to current calculation (i.e. 1000x more lumen outside than inside, so 1000x more current ), but where does the 90db (30000 to 1) math factor in?

14. Nice to see a hit n miss. Coming from software side transitioning to the hardware. Nice to see some of the different things are just the same. >;)

15. The answer is simple, a solar powered device with a small rechargeable battery that you can charge outside!

16. 90dB is a billion to one ratio

17. “You can fly to the moon on 12mA!”

18. Not in Cars…Dave :0) so you have to use a transformer or SMPSU but at least you get your wide bandwidth light source. as for the floresent lamps and many other lights their bandwidths are very peaky so power over B/W gives a very low average as far as high energy photons for generating electrons o any Si solar panel.

19. Digikey are out of stock :(

20. why don’t you run your LCD with an arc reactor

21. Perhaps 25% of the compact flourescent lamps I have purchased recently have failed within a couple of months.

    Considering how much energy must go into manufacturing one, I would like to know at what lifetime the “energy saved versus normal bulb” crosses the “energy consumed to make it versus normal bulb”….

    I suspect it’s pretty far out meaning these only make sense for long-burning applications, but they also have to stay cool, or else they fail. A difficult combination.

22. Show more of your project! Take us along the journey as you’ve started too with the solar idea. So whats your next step?

23. Incandescent bulbs are now BANNED in Australia! Oh boy, I feel a rant coming on!

24. I think part of the problem is also that spectrum of fluerescent tubes (and LEDs) isn’t good for Si cells. They like more the infrared part, so it should work better under incandescent sources.