small piezoelectric buttons for a no-battery keyboard?

Comments

• LoopyByteloose Posts: 12,537

  2013-09-08 10:01 edited 2013-09-08 10:01

  Parallax has sold a piezo-electric sensor in the past that might do. While it is a through-hole item, the tabs could be bent 90 degrees to make a keyboard configuration. I am not sure if these tabs can be cut down or ordered in smaller sizes, but at $2.50 each frop Parallax.. it may be prohibitively expensive.
  
  You might use a super-capacitor for storage of power generated to drive your keyboard communications and encoding. These on a separate backplane would provide the power from all the button pushing.
  
  http://www.parallax.com/product/605-00004
• xanadu Posts: 3,347

  2013-09-08 10:17 edited 2013-09-08 10:17

  You mean the "clicker" remote style buttons? Their mechanical nature and distance they need to emit, smaller may not be better. Are you talking a full size 101 key keyboard?
  
  I am not sure if this helps, but a piezo disc element by itself generates a small amount of voltage when tapped hard enough. I have a pile of them but they're probably too large for a keyboard. When I saw this I ordered a pile of them - http://youtu.be/Xuw9frP1GNo
• Reach Posts: 107

  2013-09-08 10:30 edited 2013-09-08 10:30

  I am specifically looking for smd piezo buttons or speakers smaller than 10 mm but I may have to settle on the 10 mm piezo speakers. Now as I type this Ill even try to use them as logic gates too a battery-less logic gate kind of interesting wouldn't you think? :thumb:
• Reach Posts: 107

  2013-09-08 10:32 edited 2013-09-08 10:32

  Thinking more on the uses for piezo devices - I would love to find a source for a very large piezo device as in FEET? Imagine a flag pole piezo device as it sways in the wind creating mega volts? My sailboat will be all electric someday.
• xanadu Posts: 3,347

  2013-09-08 10:40 edited 2013-09-08 10:40

  I don't know much about it, but in working with larger piezos I can tell that anything less than 10mm may not be able to produce a workable signal. If it did I think it would need to be spring loaded with a striker, like the ol "clicker" remotes.
  
  I find a battery-less very interesting, especially the stuff people are doing with peltier and energy harvesting. Crystal radio is another one of my all time favorites Solar not so much but hey maybe it can be a hybrid design and use more than one way to produce the power.
• Reach Posts: 107

  2013-09-08 14:10 edited 2013-09-08 14:10

  So how large are the piezo's you're working with? Im very curious to harvest energy too.
  
  I'm thinking that if I cant find BIG piezo's then i would sew many small ones into a fabric and hank it on my jib sail allowing it to flap freely in the wind. better yet drag it in the sea during a storm - but water penetration would be difficult to overcome cheaply.
  
  On the button topic the power needed could be small for my project.
• xanadu Posts: 3,347

  2013-09-10 10:42 edited 2013-09-10 10:42

  They are 50mm diameter with wires soldered on already. http://www.eio.com/p-33137-avx-kbs-50da-1c-piezoelectric-acoustic-generator.aspx
  
  They sent me a box of them 50 I think for $10 plus shipping. They seem to produce good voltage with little mechanical action, I guess due to their size. I can't even remember what I was going to try to use them for
  
  I sail too. As far as dragging stuff goes I always thought about dragging copper and aluminum conductors to produce some power but haven't tried.