It's been proven over and over that you can make batteries out of fruits and vegetables such as lemons, potatoes, and even apples. Turns out, passion fruit is also acidic enough to power a battery, but Maui Makers member Ryan K decided to take it a step further by adding a laser.
Passion fruit, or Lilikoi as it's called in Hawaii, is usually over-abundant in Maui, so Ryan decided to put it to good use. Using anodized bolts, copper pipe, wire, switches, and some LEDs, he built a battery that charges a 6800 uF capacitor.
Once the charge reaches 3 volts, the laser can be fired. Watch closely in the video below to see it in action.
It may only light up for a split second due to draining the charge so quickly, but it's still pretty impressive. The guys at Maui Makers say that 2 days later, it was producing about 1.8 volts and was (predictably) starting to get "fragrant." The cool part, though, is that all it would take is some more fruit to have it up and running again, which means its power supply is basically unlimited as long as they don't run out of fruit. And they could probably increase the charge by chaining a few of these batteries together, which would mean they could power the laser for longer, or use it to power something a little bigger.
What are some of your ideas for other small devices that could be powered with fruit?