Tilt switch for shop light

Discussion in 'The Projects Forum' started by trader007, Mar 28, 2013.

  1. trader007

    Thread Starter Active Member

    Feb 27, 2010
    222
    19
    I made this pretty awesome worklight, and I have everything done except the power switch.

    basically, the switch needs to fit inside a 1/2" gas pipe.. and I would like it to open contact only when the light is hanging directly upside down (its on a reel, so when wound up and hanging, the light should be off.). any other position it should be on.

    I am going for all out durability, so im trying not to use a toggle switch. but this gaspipe gets pretty warm, so I would need an operating temperature around 150degF. its a 12v 1a load, but I could add a transistor if I have to.

    I searched a few threads on here, but I really cant find anything. an accelerometer would work too, but im not familiar with what I should get.
     
  2. DickCappels

    Moderator

    Aug 21, 2008
    2,648
    632
    How about using two metal contacts and having a ball bearing roll onto the contacts when tilted?

    Alternatively, you can buy a accelerometer chip from Analog Devices and measure the change in the pull of the earth's gravity along one axis as the chip is tilted.
     
  3. MrChips

    Moderator

    Oct 2, 2009
    12,421
    3,357
    Mercury switch?
     
  4. Metalmann

    Active Member

    Dec 8, 2012
    700
    223
    Do you have pics you could share?

    I was also thinking Mercury switch.
     
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    A mercury switch will conduct anywhere within a 180' half-sphere, so it won't give the safety aspect of only turning on in ONE position.

    You can do it with 3 mercury switches in a star, with a small amount of "cone" effect. With the 3 switcvhes in series, that will only turn on when the "cone" is exactly upside down, on its nose.
     
  6. trader007

    Thread Starter Active Member

    Feb 27, 2010
    222
    19
    it has to be cheap and very durable. it cant be mercury.

    i found some optical tilt sensors at the 15deg rang, which is just too much. i wanted something that would only turn off the circuit when the sensor is within a few deg of dead vertical.

    so i scraped that idea, and pieced and cobbled together this. a little more complicated then what i wanted, but it should be good from about -40C to 150C+. all parts numbers are because they are the cheapest through-hole components i could find on digikey... i needed through hole to make assembly easier.

    [​IMG]

    im not sure how it will exactly perform though. once the timer has started, and the piezo trips again, does the timer restart? i hope so, because it would be annoying to have the light go off every hour even when youre working with it all day long...
     
    Last edited: Apr 1, 2013
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