Pictures of how the magnetic docks work


  1. shadowdude777

    shadowdude777 Well-Known Member

    So it's no secret that the super-special-awesome multimedia and car docks use magnetics to get you into that mode. But I got curious just now, so here is what happens when you put 1/4" cube neodymium magnets on certain spots on the device. If you already figured that this is how it works, good for you. :)

    These pictures are terrible, yes. You can click on them to see them in their full-sized horror. I didn't make a point of being artistic here, I just want to show you what happens. And yes, that is a box of Sensodyne. It was on my bathroom vanity, which is the best-lit area of my house at nighttime. :p

    This is where you want to put the magnet to activate the sensor.

    [​IMG]

    But the polarity is the key to choosing which "dock" gets activated. I don't have a polarity indicator to tell me which pole is which, but suffice it to say that one pole activates multimedia, and the other activates car.

    [​IMG]
    [​IMG]

    I tried this with 5mm diameter, 1mm thick neodymium disks, but they didn't work. That's the only other size I have besides 1" cubes which I'd be afraid to put by my phone though.

    You may want to look into something like 5mm by 2mm or 10mm by 2mm or something. 1/4" cubes aren't very compact if you're looking to be thrifty and make your own dock. You could just slip a thin disk into your design and it'd be totally discreet. Hey, making your own dock or buying an el cheapo one and slipping in a 10 cent magnet sure beats buying a $30 one, doesn't it?

    This also shows us that there may not be any more special docks to come, and if there will be, they won't be based on this technology. After all, both poles of the magnetic sensor have already been used.

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  2. GrandMasterB

    GrandMasterB Go Go Gadget Flow! VIP Member

    That is very cool , thanks for posting. I would buy the $30 dock in a heartbeat if it was available. Alas it cannot be found where I live or online :(
  3. shadowdude777

    shadowdude777 Well-Known Member

  4. DaveInNYC

    DaveInNYC Well-Known Member

    Does it matter where you put the magnets? I am hoping to make an app that will put the Droid to sleep and wake it up in a magnetic holster, the way my BB does. If there are truly only two possibilities (i.e. one for each pole, and location does not matter) I will have to disable either the car dock or the multimedia dock (most likely the latter).
  5. blazingwolf

    blazingwolf Well-Known Member

    I wonder if the magnet you are using is stronger. When I did mine it had to over the battery door at a diagonal down and to the left of the battery door slot. The polarity thing is right on though.
  6. shadowdude777

    shadowdude777 Well-Known Member

    I found that this is the best place to stick it. It seems the magnet is right under that spot. But it did work for me as far away as that "tab" on the top of the battery cover where you put your finger to pull it down and remove the cover. Obviously, the more powerful the magnet, the more freedom you get. You could probably put the magnet anywhere you wanted if you used a 1" cube, for example. ;)

    So location DOES matter. You really should put it on that location I suggested. I tried all sorts of wacky combinations with two magnets to try and enable both at once but it doesn't work too well.

    The only really solid way I can think of to make an actual two-option dock instead of having to pop out the magnet and switch it manually is to build a circuit attached to an electromagnet and switching the pole with a three-way switch (negative, off, positive). But if anyone has any better ideas, please post them! :)
  7. blazingwolf

    blazingwolf Well-Known Member


    There is a small area of where you should be putting the magnets but this can be changed with the size of the magnet apparently as the location here is a bit different then mine.
  8. shadowdude777

    shadowdude777 Well-Known Member

    That spot worked for me too, actually. Both of them seem to work. I just prefer the other spot because it's not smooth and rubberized so it actually has some grip on the magnet and it's probably more secure if you decide to stick the magnet to the phone itself to do it over there. :)

    EDIT: Hmm, I wonder what would happen if you put an electromagnet driven by an AC power source over that spot! Would the fluctuations in polarity make it detect both! Now that's interesting. Maybe at a low enough frequency it would work. I wonder if there are any electronic circuit parts out there that would convert a battery's DC to a low-frequency AC current. Now this is getting interesting. To me anyway! =D
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