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Basic Electronics » Powering your NerdKit

April 25, 2012
by HexManiac
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Using the 9v battery supplied with your nerdkit is great to get you started, but quickly becomes expensive in batteries and totally inadequate when you start driving servos and motors etc.

The 'Wall Wart' option is one way to go, but I may have found a better way.

I bought this on eBay some time ago, it's designed to power an external ATA PATA hard drive so it has both 12v and 5v outputs, both rated at 2.5A, with a common ground. Search on 'ide to usb' and you'll probably find something similar. Cost? Around £5. Alt Text

Just for reference, USB power is 5v at up to 250ma per device, and the default ATMega168 configuration (with backlit lcd screen) needs around 50ma.

If you need even MORE power, consider the PSUs sold as laptop or lcd display power supplies, generally they are 12v, at 3-4A.

Another tip, if your 7805 regulator is getting too hot for comfort (they usually start to limit current before they burn out, but that will drop the voltage and whatever you're powering may not work right), fit a heat sink to it! You can buy them for very little money, try searching for 'TO-220 heat sink'.

If you STILL need more power, rip the ATX PSU out of an old pc!

I hope this is useful...

April 25, 2012
by hevans
(NerdKits Staff)

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Really good tips HexManiac. Thanks for posting them.


April 25, 2012
by Ralphxyz
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HexManiac, you should post this in the Nerdkit Community Library it will always be here in the forum but in a couple of days one would have to know it is here in order to search for it where as the Library is setup as a reference.


April 26, 2012
by HexManiac
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That sounds like a good idea Ralph, how would I go about doing that?

April 26, 2012
by Ralphxyz
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Start out at the Library.

I think there is a new login required.

You can choose which topic line to place this under. Of course you can put links to "Powering your Nerdkit" under any of the topics.

You might start in the FAQ topic.

So after you have logged in goto the FAQ page.

Then down in the lower right hand corner there is a "edit this page".

Now you are just going to do what has already been done so if you read the edit FAQ page you will see how to add a new subject.

The first three lines read:




So to make a "Powering your Nerdkit" page you would:

###["Powering your Nerdkit"](/library/Power/)

Preview and Save.

Then go back to the FAQ and you will see a new link Powering your Nerdkit.

Click on this link and you might be prompted about making a new page so go ahead and edit it.

The Library is powered by the same limited Markdown syntax as this forum.

You can copy paste this thread and edit and enhance it.

If you are starting from scratch it is probable easier to use a text editor and copy paste from that.

You learn by looking at the other pages to see how things were done.

You can click on "edit this page" on any page to see how it was done just do not save it when you leave.

Actual even if you did save page you were just looking at the text would remain the same (unless you changed something) and you would be attributed with the last edit.

I have some attributes just because I edited a page just to correct a spelling or to change the layout of a page not that I originated the page.

The Library is a WiKi format meaning is is open to the community to contribute and to police and maintain.

Everyone is encouraged to contribute even if you are not a "expert" basically if you have something to say, you think of value then please contribute. If there are errors then it is up to the community to make sure everything is accurate and factual.

If we had a little more sophisticated engine driving this there would be email and discussion threads about posted subjects. All of that was done on bulletin boards years before there was a Internet so it is a shame we have such a outmoded engine to drive the Library and this forum.

Let me know if you want some help off line rhulslander gmail.


April 27, 2012
by HexManiac
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Thanks, I've done as you suggested.

April 27, 2012
by Ralphxyz
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See there ya go, easy right.

Thank you,


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