Cooking up piezo crystals at home

piezo_crystal

[Collin] loves piezos – and why not?

According to him, they are about as close to magic as you can find in the world. We can’t really disagree on that one – there’s something oddly enchanting about piezoelectric materials.

Most commercially used piezoelectric devices that you find today are constructed out of man-made ceramic materials such as Lead zirconate titanate, and can be found in grill starters, gas-powered water heaters, etc. While they are common, it’s not exactly easy to synthesize these sorts of ceramic materials at home.

You can however, create piezoelectric crystals in your kitchen, using just a few simple ingredients. In his video, [Collin] shows us how to create Rochelle Salt, one of the first known materials found to exhibit piezoelectricity. The recipe calls for three ingredients, cream of tartar, sodium carbonate (soda ash), and water – that’s it. The procedure is quite simple, requiring you to heat a solution of water and cream of tartar, adding the soda ash a little at a time once it reaches the proper temperature. The solution is filtered after it turns clear and then left to sit overnight while the crystals form.

Take a look at the video embedded below to see how his Rochelle Crystals turned out, and be sure to try this out with your kids if they are interested in electronics. Making crystals that generate electricity when tapped is far cooler than making rock candy any day, trust us on this.

56 thoughts on “Cooking up piezo crystals at home

  1. I’m assuming that you can you standard crystal forming procedures (such as very slow cooling) to make uniform, “pretty” looking crystals.

    Looks like we’ll have to become magicians now!

  2. This guy could present a video in his sleep and it would be entertaining and informative. As always, brilliant stuff.

  3. It also looks like he’ll be able to store our planet’s knowledge to teach his son after our star explodes.

    just sayin…

  4. Nifty. I’d imagine to produce sound with it you would want to attach it to a diaphragm. It’ll probably take a fairly high voltage to be audible.
    Because the excursion is very limitted it’s probably only good from 1kHz up too. IE don’t hook it up to a wall socket and expect much.

  5. That’s cooler than when I ‘discovered’ that Epsom Salts are mostly water, and you can literally toss them on a hot stove element and they’ll boil away to a white powder. I may have to try it, I’m wondering how resilient they are, and stuff like that.

  6. You need to make sure that the neighbors and the cops know that you’re cooking piezo crystals and not the meth kind. Just owning a few of the components to make the crystals is enough to be charged with precursor chemicals. Just as long as you have documentation, you should be ok.

  7. i’ve wanted to make 1 of these since i was like 5(i wanted to make sparks like the commercial piezo devices) but i was never able to find Rochelle salts

  8. I’m curious to know of any dopings one could do at home to make this a home-brew semiconductor of some kind. (e.g., home-made transistors and the like)

  9. @Lewis: “a few of the components”? Which ones?
    Cream of Tartar? Used in baking
    Water? Please…
    Sodium Carbonate? As stated in the vid, it’s commonly used in arts & crafts.

    I don’t see how purchasing/using any of these items would be suspicious as they’re pretty common.

    Just don’t make these piezo crystals when you’re taking cold meds, and you should be fine.

  10. Piezo discs are often used as impact sensors in electronic drums. I wonder if I could use this to “grow my own” drumkit?
    Of course, they would only be useful as “rock” drums. :)

  11. He was wanting to make a microphone, i wonder if a jewelers saw would do the trick to make a thin wafer.

    /not sure how brittle these crystals are.

  12. If you suspended a piece of sheet metal so one side was submersed then you might be able to get a thin crystal to grow on it. you might have to seed it with some ground up crystal to get it to grow too the metal.

    1. Maybe you could grow long crystals by using a small starter seed and suspend it into the top of the solution and slowly raise it out of the solution as it solidifies like they grow semiconductors, it might work

  13. I’m guessing the electricity giving off is too minute to actually power anything?

    If he were to connect an LED, would have see it light up with each strike?

  14. @Lewis
    You are partially right. There are police who monitor the sale of certain chemicals that are precursors to common drugs. Most of the chemicals that are monitored require a signature in order to purchase them.

    For this, most of the ingredients should already be in a well stocked kitchen; or the kitchen and cleaning closet. Not sure about the rochelle salt, but I am sure there is a good use for it around the house as well.

  15. who is he fooling with that hair cut? XD

    nice … is try pulsing hv in to that and try and produce some noise!

    @Lewis
    nothing here can be used to produce anything illegal
    police many lookout for large purchases of baking soda, cough medicines, anti allergy medications, acids, salt peter and salpher and recently lithium batteries

    1. And alcohol… don’t forget the distilled liquers! Seriously though, WTH. Next thing, you’ll tell me that they break into peoples homes just for having a high electric bill. Oh wait! ;)

  16. i’m wondering just how much these put out… if carved into keys would they be enough to trigger a pic or atmega looking for voltage changes? If so I can see a crystal keyboard in my future. Buahahaha

  17. Tapping that thing with a oscilloscope connected is all well and good, but what else can you do with it?

    Like, those little piezo igniters? Can this be modified in such a way to make cool sparks at night?

  18. How brittle is this material? Would it be possible to crush it into a powder? I was reading on Wiki that Rochelle Salt has a melting point of only 75 degress C. I was thinking that you could grind up the crystals, sieve the powder onto some form of teflon coated/non stick tray, and put them in an oven just over 75. Wait until they’ve melted together and it should form a sheet. I’m not sure if that would actually work, all I know is that it works with caramel.

    1. Right to start with yes you can melt these crystals but no they do not make one big crystal when it all cools down. “Well not with my experiment anyway” It becomes a white brittle powder-like-substance”

      Solving the Soda ash problem; well not really a problem depending where you live I suppose but I found my ready-made Soda Ash among the swimming pool cleaners in our local Store. My Cream of Tartar was a problem as there are many synthetics with the same name. Go to your local bakery supplier, they will sell you the proper Cream of Tartar.

      I used demineralised water to help with saturation. The solution is crystal clear when done.

      My processes is still experimental at this stage but my results are golf-ball size crystals but they are very brittle indeed. “useless” any idea to solve this Brittle effect? I am thinking because I force cool them that they become so brittle?

  19. @Lewis. None of the compents are apperatuses, or methods are illegale as susch what you do in your own property is all good. No excuse me while I get myself registered so I can make purchases at the hardware store

  20. Thats cool, Going to go cook me a batch of crystal now ;)

    I was wondering would it be hard to get the crystals to form around wires dipped into the mix or by melting them to a desired shape and embedding wires?

  21. Sodium Carbonate is also available in the grocery store which may be easier than finding an art store. Look for Borax washing soda in the detergent aisle. It can also be made using Sodium Bicarbonate by heating in an oven at 350F for two or three hours. Heating and melting Rochelle Salt will try to recrystallize as a crystal, and not a sheet.

  22. The link for the recipes that he posted is the one that I’ve used previously- it gives great results.

    http://www.seawhy.com/xlroch.html

    Other links on there include ways of creating different colors, shapes, seed crystal growing, etc.

    For those of you more interested in the mechanics of piezoelectrics, check this out: http://rimstar.org/materials/piezo/rochelle1.htm. He shows how the voltage produced by a crystal varies with force, pretty interesting for those of us that prefer to have empirical explanations rather than “it just works” or “it’s magic”.

  23. I tried this out last weekend after watching the video, and I did find that the first time the solution crystalized it was really more of a sticky salt, I didn’t get crystals until I re-dissolved it (into VERY little VERY hot water) and let it sit again, I got a couple of nice (albeit small) crystals out of it.

    And yes – washing soda is much easier to find, for me, than soda ash, and they’re the same thing.

    I have a thought for a microphone, I may try to tackle it this weekend. Bear in mind the super-high impedance of crystal mics may make them complicated to amplify without some extra electronics.

  24. Another place to get sodium carbonate other then art stores is in the pool chemical areas of stores. Soda ash is used as a pH increaser in swimming pools and hot tubes.

    1. You want a single crystal for this to work. The crystals need to be cooled gradually after being heated to past their melting/annealing point.

  25. Just tried to use this for an AP Physics project. I was totally convinced it would be easy and I’d have one of the coolest projects. Instead I botched two batches of crystals, let down my group, lost $30 on ingredients, and pretty much threw my entire project off track. I don’t even know what I did wrong! I’ve talked to several chemistry teachers and we came to the conculsion that the first time I burned it, but we have no idea what happened the first time. Two days after the fact, the first burned solution has solidified to the consistency of a slightly melted slushy, but I really just am confused beyond belief about what’s going on. HELP!

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