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Another Camera Power Supply for Canon DSLR

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#1 Midnight Dan

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Posted 27 November 2011 - 07:31 PM

This post is a follow on to Arctic Eddie's Camera Supply project. He and I had talked about these step-down voltage converters at a ridiculous price on ebay and we both decided we would create a supply for our DSLRs. Mine is for a Canon D1000 and is very similar to Eddie's but with a few differences.

Here's a picture of the parts I used - more or less. The parts list changed a bit after I took this photo:
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I purchased an AC adapter for my camera like Eddie did. In this case, the adapter came with a dummy battery to put in place of the camera's normal battery. Originally I planned to use a die-cast metal case like Eddie did to cut down on any potential RF noise from the switching supply, but all I could find at my local radio shack was the plastic one pictured. I hope I didn't make a mistake using plastic!

The next photo is the initial assembly, mounting everything except the regulator board:
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Note that I have a switch, a red LED, and a power jack on mine. I like the idea of having a power light so I can tell if I accidentally left something on that's draining my battery, so I included the red LED. The power jack and switch are to allow me to plug in the AC adapter and use the switch to select where the power comes from.

When the switch is to the left, it uses 12VDC coming in from the cable, through the regulator, and out the output cable. When the switch is in the center position, it is off. When it's in the right position, 7.5 VDC comes in from the AC adapter, into the power jack, and directly to the output, bypassing the regulator.

Before installing the regulator board, I wanted to be sure it would work and to adjust it to the correct output voltage for my camera:
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Here's the final assembly with the regulator installed:
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Before the final assembly was complete, I tested the Red LED and found it was WAY too bright, even though it had a built in resistor. I added a 4.7kohm resistor in series with it to tone it down a lot. In the photo above, the resistor is hidden inside a piece of shrink tubing coming from the red lead on the red LED>

... and here's the whole thing buttoned up:
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The final photo is the whole system as it is intended to be used:
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I chose an RCA connector for the 12VDC input because my DewBuster uses that for its 12V convenience outlets, and I use it as a power distribution box. The AC adapter will normally not be used, but if I want to, I can plug it into the power jack, flip the switch the other way, and use AC power.

My design is a little more complicated than Eddie's and my box looks more like 10 pounds of stuff crammed into a 5 pound bag! :grin: After looking at Eddie's I like his clean design a little better, using adapter cables instead of the switch and power jack. But I just thought I'd show a little different take on the same kind of project.

These little voltage step down boards are very handy, and very cheap at $2.15 each! I bought 3 of them and have put the others aside for future projects.

-Dan

#2 Arctic_Eddie

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Posted 27 November 2011 - 07:54 PM

Excellent job Dan. That's much more versatile than my approach. This will give the readers several ideas on how they might use these regulator boards.

I may have to go back and add an indicator light to mine as it's easy to forget to unplug the regulator input. However, if the camera is shut off then the current may be too low to worry about for a day or two.

#3 Radiostar

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Posted 27 November 2011 - 08:27 PM

Nice work you two.

#4 Midnight Dan

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Posted 27 November 2011 - 08:33 PM

Thanks Eddie. And that reminds me, I did do some current tests to see what kind of load this thing puts on the 12V supply. Hooked the camera supply box up to a 12V supply and this is what I got:

0.0085 amps - Box turned on, Camera off
0.041 amps - Box on, Camera on, rear LCD off
0.090 amps - Box on, Camera on, rear LCD on for data display
0.275 amps - Box on, Camera on, using rear LCD for LiveView

Again, this is with a Canon Rebel XS (D1000).

At 8.5ma with the camera turned off, the reducer board really draws surprising little!

-Dan

#5 Arctic_Eddie

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Posted 27 November 2011 - 08:52 PM

With your 5Ah NiMH pack that's 24 days of life. A Ni pack might drain itself in that time. The LED indicator will draw about that much. I may still add an indicator to my setup.

#6 Midnight Dan

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Posted 27 November 2011 - 09:04 PM

With your 5Ah NiMH pack that's 24 days of life. A Ni pack might drain itself in that time. The LED indicator will draw about that much. I may still add an indicator to my setup.


The current readings above are for the finished box, so they include the LED current draw with the 4.7kohm resistor in series. With the LED running off 7.5v and the resistor in series, it should be drawing around 1.5 ma, so the other 7 ma must be from the reducer board. Any way you look at it, it's not much!

-Dan

#7 mfulmer

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Posted 02 March 2012 - 10:54 AM

Bumping this thread to see how the power supply has worked out. Did the voltage regulator perform well over time? Any issues with RF noise? I'm putting one of these together myself, so I'm hopeful all has worked out well.

#8 Arctic_Eddie

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Posted 03 March 2012 - 06:47 AM

Dan probably sees comparable results to my version using the same regulator. It runs for hours with no noticeable warming and no noise is seen in the camera images. I have a pair for two different cameras and now building a stepper motor/rotary encoder remote focuser using the same regulator. The price of the board has dropped to $1.97.

http://www.ebay.com/itm/260858526297

#9 mfulmer

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Posted 03 March 2012 - 02:02 PM

Thanks. That's good news. I've got three on my way from China as I type.

#10 Mike Clemens

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Posted 03 March 2012 - 09:52 PM

> At 8.5ma with the camera turned off, the
> reducer board really draws surprising little!

Sounds likes a switching power supply. How much input voltage does your power regulator board require to operate?

#11 mfulmer

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Posted 04 March 2012 - 12:27 AM

Input voltage is rated at 4.5-40V for the board Eddie links to in his latest post.

#12 ccs_hello

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Posted 04 March 2012 - 09:46 AM

...
Sounds likes a switching power supply. How much input voltage does your power regulator board require to operate?


Yes, that module is a step-down switcher.
LM2596 when operated at full 2A output current-draw at 25 degrees C ambient has the drop-out voltage of approx. 1.2V.

So if the regulator is set at 7.8V, then the minimum input voltage required is 7.8 + 1.2 = 9V. In reality, the voltage can be a bit lower.

Clear Skies!

ccs_hello

#13 Mike Clemens

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Posted 04 March 2012 - 03:18 PM

That is an amazingly low price for those buck regulators complete, just the coils on that are probably more than that price on digikey. I'd love to find one with a smaller footprint ready to go like that.. is that thing truly over half an inch thick?

#14 Midnight Dan

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Posted 04 March 2012 - 03:50 PM

My results are the same as Eddie's. No image noise, no heat at this current drain, and long battery life.

Mike: I measured one of my spares, The thing that sticks up the most is the adjustment screw on the voltage pot. If I include that and the component leads that stick out slightly from the bottom of the board, I get:

Thickness: 0.558"
Width: 0.811"
Length: 1.708"

-Dan

#15 Arctic_Eddie

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Posted 04 March 2012 - 04:15 PM

PM sent back to you Mike with more details.






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