Saturday, May 23, 2009

my "sun jar"

Tried to make my own "sun jar" around a year ago. Left it on breadboard until today...



Find the schematic below. Added a switch to keep the LED off all the time... which effectively makes the whole thing a solar powered battery charger...



Notes to self:

  1. The solar panel is directly connected to the battery for charging. Without any control on voltage or current. May damage the battery in a long run. But then, the solar panel used is not that powerful... so....
  2. A normal LED requires more than 1 AA cell to power it up. To overcome this, the center-tapped-coil and one of the transistor formed a switching circuit. It generates voltage high enough to light up the LED with less than one volt.
  3. Unlike the commercially available Sun Jar, this circuit doesn't use photoresistor to control when to light up the LED. Instead, a transistor is used to detect the voltage output of the solar panel.


2 comments:

Jay Campbell said...

Your video has been marked as private so it cannot be viewed. I am trying various circuit combinations that will yield the most efficient output to make a sun jar also. Thanks for posting your circuit!

Clarence said...

Hi Jay. Didn't realize that I changed the video to private. Just changed it back to public. Happy hacking!