Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Power Supplies

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
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DDavid

Power Supplies

Post by DDavid » 29 Dec 2009, 18:44

Would it be safe to have one PS for the cameras and triggers? I
have quite a few rechargeable batteries but still. My one Canon
CA-PS500 PS has died and I'd rather not replace it right now if I can get by
with something else safely.
I also have several batteries for RC
planes and such that run around 6V which would likely run 2 cameras
all day and could use resisters I think to drop the voltage which might be
safer. Could some of you smarter than me comment?

phaedrus
Posts: 56
Joined: 04 Mar 2014, 00:52

Re: Power Supplies

Post by phaedrus » 30 Dec 2009, 00:47

Hi David, I'm not sure what voltage your camera requires but resistors definately won't do the job, you must use a proper regulator.

If the difference between the input and output voltage is not too great and the current draw not high (say < 500ma to be on the safe side) you could use a simple 3-terminal regulator if there's one available at a suitable voltage. Otherwise one of the small DC-DC converter chips would probably do a nice job.

I don't know what others have done and don't have access to the cct for the camera so not completely certain about the advisability of using the same source for the trigger voltage as well as the camera - certainly not above 5v and given the miniscule current drawn it may be safer to use a button battery. That said others may have have a more informed view on this than I do.

Cheers, P.

Turtle
Posts: 40
Joined: 04 Mar 2014, 00:53

Re: Power Supplies

Post by Turtle » 30 Dec 2009, 10:03

DDavid wrote:Would it be safe to have one PS for the cameras and triggers?
Yes. It will be safe but the moment you enable the flash the camera might just turn itself off. Just make sure to turn off the flash before powering down.
DDavid wrote: I have quite a few rechargeable batteries but still. My one Canon
CA-PS500 PS has died and I'd rather not replace it right now if I can get by
with something else safely.
The power supply may have died but unless you test it, you could be looking at just a bad plug.
DDavid wrote: I also have several batteries for RC
planes and such that run around 6V which would likely run 2 cameras
all day and could use resisters I think to drop the voltage which might be
safer. Could some of you smarter than me comment?
There is a way to run two cameras (at 3.15V) and a camera trigger on the 6-Volt RC battery pack without using any parts such as a regular. All you need is what you said you already have, plus a soldering iron.

In conclusion, you now have two options for this to work. I like the first option. That is to have one PS (power supply) for the cameras and triggers.

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daniel_reetz
Posts: 2786
Joined: 03 Jun 2009, 13:56
E-book readers owned: Used to have a PRS-500
Number of books owned: 600
Country: United States
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Re: Power Supplies

Post by daniel_reetz » 30 Dec 2009, 10:26

Some cameras will trigger on as little as 3V, so you can probably just tap off a normal adapter. AFAIK, there's no electrical reason not to use the same power supply as is powering the cameras, provided it will trigger reliably.

On eBay, there are powershot power supplies for as little as $11.99. I hope to buy some of these to install in the base of my portable scanner.

While I was home in Bismarck visiting family, I decided to employ my Mom's Powershot A95 to digitize all the old family pictures. Because we have thousands of family pictures, I really needed a power supply.

The A95 supply voltage is 4.3V, 2A. I took a 5V, 1A supply from an old Zip drive, hacked the end off. I found a bridge rectifier in an old 10baseT hub and connected 1 segment of the bridge rectifier across the positive lead to drop the voltage (a bridge rectifier is just 4 diodes in a bridge configuration, they are usually designed to handle a couple amps). Since diodes typically drop .7V my camera received the correct 4.3v. It complained constantly that the batteries were low, but it took over 2200 pictures over the Christmas holiday with zero problems.

I will post pictures later.

DDavid

Re: Power Supplies

Post by DDavid » 31 Dec 2009, 23:59

Thanks for the replies.
Turtle I even cracked the case and it definitely is not the cables. That was my first thought too.
Daniel I've ordered 2 PS off fleabay, the price has dropped quite a bit since I bought the one that
died. I'm lucky I have been into Canon's for years. I got into them for the camcorder like flex screens
for down and dirty copying from books.
If my Mickey Mouse tablesaw will hold on a little longer I should have a somewhat functional
scanner this weekend.
DDavid

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