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Tutorial: atx power supply -> camera power supply

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bimbo111
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Tutorial: atx power supply -> camera power supply

Post by bimbo111 » 04 Feb 2013, 22:22

I wanna start out by saying that i've only tested this with my a3300s and that you should consider the risks of supplying you cameras with inappropriate voltage. Compared to whatever tweaks (chdk etc.) we are using on the cameras, this one has a real chance of frying your camera! Also remember to unplug the power chord as an extra precaution whenever you have to touch wires directly.

All right.. Enough about safety. I've allready written about this in the a3300 thread, but consider it a bit hidden from the users of different cameras so i thought i might post it here as well.

The idea is, that while most official ac-adapters are quite expensive some of us have atx-powersupplies floating around the house that could be used for this purpose. Here's my a3300 powered from an atx powersupply:

Image

Though the battery for my cameras supposedly delivers 3,6 volts i can power the camera with one of the outleds from the atx supply, even though it only delivers 3,2 volts (measured). In other words my camera can accept a variety of voltages and still function.

You can see from this pinout diagram from where you can draw the desired 3,3 volts:
Image

If the 3,3 volts is not enough for your camera you could consider using one of the other pinouts and maybe lower the voltage with diodes. This i haven't tried.

As you can see on the image above there is a 'power on' pinout. This must be connected to any of the 'grounds' in order to turn on the supply. This equals pressing the power button on the computer.

To get access to the pins you can either do it the brutal way and just clip off the desired wires from the cable or buy an extension cable as i've done. If you do so, you are still able to use the supply with a computer, if you should need that one day.

Next comes the tricky part of actually feeding the power to the camera. The best way i could come up with is to create a copy of the battery and put in conductors at the places that the original battery has them. So measure the dimensions of the original battery and create a copy from a piece of wood of the same thickness. I found mine in the trash of the local woodshop.

Here is a sketch of the wooden copy you'd wanna create:
Image

The light grey represent the actual conductor (solid wire is more easy to press through), while the darker grey is solder. The solder is there to prevent the conductor from being pressed backwards through its hole when being pressed against the pins of the camera. The polarities was specified on my battery, but you might need to measure them yourself or look it up somewhere.

To accomplish the above you need to drill the whole way through the wood with a thin diameter and then - only in the top - you need a bigger hole for the solder. The drilling part should be done with a benc drill:

Image

It can be a bit tricky to get the solder into the wood without burning it too much. Applying the solder on the wire and then pulling it from the other end helped me.

Once you have the wires in place try and connect it to the atx supply and see if it works. As far as i know there should be no difference between the different 'grounds'. If i does not work you may need to reposition the conductors. I was lucky to get it in the first try. Last put on some heat-shrinkable tube on the wires comming from the back of the wood to avoid shortcircuting when closing the battery lid.

Thats it i think! I have not included any measures, since it can vary from camera to camera, but write me if you would want any measures from the a3300 is. Also this guide has been written on an iphone in the middle of the night so bare over with my spelling :)

Image

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daniel_reetz
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Re: Tutorial: atx power supply -> camera power supply

Post by daniel_reetz » 05 Feb 2013, 00:48

Great tutorial - and nice pics. Thanks for sharing this. There were some other tutorials of this nature posted by Marcos Kusnick. Unfortunately, I'm on my phone, so I don't have links to those tutorials right now.

tresho
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Re: Tutorial: atx power supply -> camera power supply

Post by tresho » 18 Feb 2013, 00:00

A suggestion in lieu of tooling a wooden block: use epoxy putty instead. It can be roughly formed and molded by hand until it hardens about an hour after being mixed. Wires and contacts can be simply "squished" into the block of putty. The only critical part is the size & spacing of the metal contacts. The hardened material can be sanded, drilled or carved.
Another theoretical use: wrap the existing battery tightly in plastic food wrap. Use epoxy putty to mold around the area of the contacts. when this mold hardens, separate it from the battery and the plastic wrap. Wrap the inside of the mold in plastic food wrap & then make another casting using more epoxy putty - this will duplicate the size, shape & spacing of the contacts. After this hardens, more epoxy putty can be added to duplicate the bulk of the OEM battery.

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daniel_reetz
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Re: Tutorial: atx power supply -> camera power supply

Post by daniel_reetz » 18 Feb 2013, 22:42

Tresho, is there a brand of that epoxy putty that you prefer? I've had very mixed results and I think it's probably just the stuff I'm buying.

markvdb
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Re: Tutorial: atx power supply -> camera power supply

Post by markvdb » 19 Feb 2013, 16:29

bimbo111 wrote:The idea is, that while most official ac-adapters are quite expensive some of us have atx-powersupplies floating around the house that could be used for this purpose. Here's my a3300 powered from an atx powersupply:
Can I please dump this information into https://github.com/markvdb/diybookscanner/wiki with your permission?

Mark
Mark
http://diybookscanner.eu - official EU diybookscanner kits - subscribe to our newsletter

bimbo111
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Re: Tutorial: atx power supply -> camera power supply

Post by bimbo111 » 25 Feb 2013, 05:53

Sure that would be cool! Good to see that the wiki is up and running again!

bimbo111
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Re: Tutorial: atx power supply -> camera power supply

Post by bimbo111 » 25 Feb 2013, 06:01

And as for the epoxy, imo the 'wooden' way to go is more simple, less time consuming and more within the reach of the ordinary diy folks. But if you have experience with the technique, i'm sure you can get a very nice result that way! And avoid sawdust in the camera :)

tresho
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Re: Epoxy putty, relative ease

Post by tresho » 28 Feb 2013, 06:06

I have been trying to remember my original type of epoxy putty I used years ago. Since then Walmart has changed the labeling on the packages it sells & I can't be sure the same material is now on sale. I don't have the original packaging, just the material stored in a ziplock bag. Once removed from the packaging, the material looks the same. The brand Walmart is currently selling is Peerless Plumbing Epoxy putty.
I would encourage anyone with a few dollars to spend to buy some of this material and play with it. There are some things epoxy putty can be used for that nothing else quite approaches. E.g, I stripped plastic threads on a camera tripod mount, drilled these out and refastened the threaded socket using epoxy putty, which became stronger than the original plastic. Another example is the base of the swiveling water sprayer inside my dishwasher. It disintegrated after several years & I was able to duplicate it using epoxy putty with an embedded stainless steel hex nut. I have received about 3 years of extra service with this fix, so the material is really durable.
At my local hackerspace last night I discussed some of the pros & cons of duplicating the battery casing, the part that fits into the camera, with a fellow that does vacuum forming & small plastic castings. Even he thought simply carving the casing from wood would be easier than casting one in epoxy, and would work about as well.
The way to make a high-quality casting would be to use specialized plastic casting materials sold at places like Hobby Lobby (see http://shop.hobbylobby.com/products/mold-putty-881540/) or at places like smooth-on.com. See the following page for an elaborate step-by-step process of making a duplicate of a Roman shield using epoxy putty: http://www.smooth-on.com/gallery.php?galleryid=494
These specialized molding compounds are quite expensive.
What I suggested in my earlier post is far simpler, but would look cruder than specialized products would yield.

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