DIY Hacks & How To’s: Pocket-Sized Power Supply

DIY Hacks & How To’s: Pocket-Sized Power Supply

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I am a big fan of garage sales, flea markets, and thrift stores. They are great places to find used parts and materials for your next project. But one problem that I often run into is not being able to test battery powered electronics to see if they work. Because there are so many different combinations of batteries that are used in portable electronics, it isn’t really practical to carry around batteries for testing. One device may need 6 AA’s and another may require 4 D’s.

So I came up with this simple pocket-sized variable power supply. It can plug into either a 9V battery or a 12V battery pack. You can then adjust the output voltage to match the device that you want to test and attach the output wires to the end terminals on the device’s battery connectors. This lets you power a wide variety of small electronics long enough to see if it works. And I am sure that you can come up with a lot of other applications for a pocket-sized power supply as well

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Check out the full project on MAKE Projects and on Instructables.

See the full series here.

14 thoughts on “DIY Hacks & How To’s: Pocket-Sized Power Supply

  1. tfraley (@tfraley) says:

    video is set to private.

  2. Darren says:

    “This video is private.” Wrong link or something changed?

    1. Stett Holbrook says:

      It’s public now. Thanks.

  3. mark says:

    If I were selling you something at a flea market/thrift store/car boot sale/wherever then I’m not sure I’d let a stranger connect up an obviously home-made piece of kit to the battery terminals. Get something wrong and there’s the (albeit small) chance that you’ll damage whatever you’re testing. Its still an interesting way of powering things when you don’t have the right type/amount of batteries on hand though.

  4. tim dolan says:

    good project but it appears that it appears on two threads in the blog.

  5. kentkb says:

    So cool! I to go to flea markets and buy old electronics, and have carried 4 AA and a 9v with me.I like this and will build one. Thanks JPS!

  6. virtuPIC says:

    Ever thought about another resistor ladder? Like R2R with some upper and lower offset to set at finer resolution? If you buy several resistors of 1% tolerance they will probably have an absolute error of typically more than 0.8% or so but if they are produces together, in the same series, their values will differ much less. You can check this with your multimeter which is much more precise in comparing resistors than in displaying their values.

    If you use an 8x switch you can get a resolution of 8 bits giving you steps of some 50 mV at a max voltage of some 12 V. If you get a cheap reference voltage chip you can even correct the voltage error of the LM317. Okay, needs some calculation. But you get the error down to the fraction of a percent.

    Airspace V – international hangar flying! for tools & toys

  7. Peter says:

    Nice one! I’ll do that.

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My name is Jason Poel Smith. I have an undergraduate degree in Engineering that is 50% Mechanical Engineering and 50% Electrical Engineering. I have worked in a variety of industries from hydraulic aerial lifts to aircraft tooling. I currently spend most of my time chasing around my new baby. In my spare time I make the how-to series "DIY Hacks and How Tos."

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