Lilikoi Laser

Ryan’s Lilikoi Laser

Maker Ryan K showed up at our Thurs Aug 15 2012 meeting with what is one of the coolest maker projects I’ve seen in a while…
A Laser powered by Lilikoi fruit!

Lilikoi (aka Passion Fruit, Passiflora Edulis) is a vine that grows all over our wet Maui regions. It can produce LOTS of fruit – which can make a mess for owners, and a bonanza for bugs. Ryan was cleaning up a whole bunch of them at his home and tasting one, realized it was pretty acidic. Being a curious Maker, he thought “Hmmm I wonder if you could make a power source with this?”

Ryan grabbed some anodized bolts (source of zinc), some thin copper pipe, wire, switches, LEDs, capacitor, and built himself a nice demonstration Veggie Battery. And since Ryan loves lasers, he grabbed a small green laser and added it to the board.

The result is very cool. An optional volt meter shows the current charge available on the 6800uf capacitor. There is an on/off switch with LED indicator light, which drains power pretty quick, a push button + Blue LED that runs nicely for long duration, and another pushbutton controlling the laser. When charge voltage reaches at least 3v (max charge is approx 3.8v), the laser can be fired, giving a brief green pulse. Adding a pweew sound is optional, as is telling the captain the power banks need to recharge before firing the next blast.

One question several people asked was “How long will it last?” Well, writing this on saturday (2 days later) I can tell you that it is starting to get ‘fragrant’ and will now only produce about 1.8v. I dont have any lilikoi around to recharge it … anyone got some dililikoi crystals?

Ryan eating one of the backup batteries for his Lilikoi Laser

Here’s a quick video showing the laser firing …

A Flickr set with more pictures:

[slickr-flickr tag=”LilikoiLaser” descriptions=”on” flickr_link=”on” sort=”title” use_key=”y” ]

7 replies
  1. Peter in NJ
    Peter in NJ says:

    Really nice Ryan! Now if we could only turn the sand into solar power arrays as easily!? Or, draw power from other plants. And while we’re at it, how about getting rid of the Telephone poles! Speaking of making things. Look what the army is doing:

    Army Sends Mobile 3-D Printing Labs to Afghanistan For On-Demand Gear

  2. Jerry
    Jerry says:

    And also on AdaFruit blog …

    One of the comments on HackADay noted that the fruit is not a battery, it is suppling the electrolyte for the battery – which depends more on the electrodes for power… well both actually. There is still a lot of electrode left, but without electrolyte we get no spark. (fuzzy lilikoi are now in the compost … probably come back to haunt me.


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