It is currently Tue Aug 11, 2020 7:28 pm




Post new topic Reply to topic  [ 6 posts ] 
 My solution to the power problem - 12V and 3.7V supplies 
Author Message
User avatar

Joined: Wed May 21, 2008 3:34 am
Posts: 45
Post My solution to the power problem - 12V and 3.7V supplies
Hi, Hopefully my information here may be of use to someone.

Because taking time-lapse sequences has to be a continuous event I decided that using rechargable AA's for the pan system and a rechargeable for the camera were a bad idea as there is nothing worse than getting part way through a long sequence and the battery going.
As I'm an electronics engineer I looked at using LM317 regulator as I've used that many times before but in the end I did not use this as you will see here.

I need 12V for the panning system (Meade controller) and 3.7V for the camera supply (Canon Ixus 430) and it must run for many hours.
The other important factor was I needed some good quality easy-to-connect method of connecting all these bits in the field without the need for tools.

My final answer was to use a 12V 7Ah Lead-acid battery in a box with two fused high quality sockets on the lid. One for panning system power and one for the camera power.
The connectors I used are 3 pin XLR connectors..
http://en.wikipedia.org/wiki/XLR_connector
These have a locking feature which means they can not be removed without pressing the latch down first :!:

By the way If anyone decides to use lead-acid or other high power supplies like this then make sure you use suitable fuses, don't risk not using fuses otherwise you may have a fire if wires short together. these types of batteries will give hundreds of Amps if shorted so be careful.

I charge the battery from a digital bench power supply, not the best solution but its easy for me to do this.

For the 3.7V supply I bought a 12 Volt Car Cigar Lighter Socket multi-voltage adaptor (see link below), this plugs into the Car Cigar Lighter socket and gives many different voltages depending on the swtich position. I changed the resistors inside so that it gave me exactly 3.7V DC and removed the switch so thats all it gave out (for safety reasons!).
I left the Cigar Lighter plug on it so I could power the camera in the car. I then made an adaptor lead with an inline Car Cigar Lighter socket on one end and a 3 pin XLR plug on the other. This adaptor allowed me to plug it into my 12V supply box.
The Canon Ixus 430 does not have a power socket so I made a false battery out of a bit of pine which I made the exact same size as a real battery. I then used Araldite to fix in two battery contacts (made from single sided bare PCB material).
Then I made a hole through the middle to put the wires through and soldered them in place. The wires emerge in the bottom of the false battery and the cable exits the battery flap through a hole.

When doing indoor timelapses I also made a 240V mains supply for the camera, Again rather than designing something from scratch I bought a multi-voltage mains adaptor (see link below) and changed it to give 3.7V. I removed the voltage selector switch.
I don't recomend you modify mains supply equipment like this unless you know what you are doing!

All the connections to the camera are via male/female bullet connectors. These allow quick connection but are reliable and are also small enough to fit through the small hole in the bottom of the Canon Ixus battery flap. Note that the +Ve output lead is always a female and the -Ve output connection a Male so that you can't accidently short the supply out. This also means you can't wire it backwards.

The cables used are the fine multistrand type so they are VERY flexible and unlikely to break. Such as this wire here..
Mulitstrand wire, very flexible

Links to bits I used :
DC/DC Switching Power Adaptor This I modified to supply 3.7V for the Canon Ixus 430.

Mains to DC Switching Power Adaptor This I modified to supply 3.7V when doing indoor timelapse work.

------------

Some photographs of my setup:
---------------------------------
1) Showing the 12V battery box with the two connections on the top of the box, Fuses to the side of them. One connection is to the panning system and one to the 3.7V adaptor for the camera via the adaptor lead.
You can also see my modified Meade controller in the shot.
Image

2) Showing the battery box opened up.
Image

3) Showing the camera, the false battery and a Canon battery side by side.
Image

4) Showing the cable that connects between the panning system and the battery box.
Image

5) Showing the panning system with the connector fitted to the battery compartment lid. The bracket on the panning head allows me to fit either a Canon Ixus, Olympus 5050 or a Nikon D70.
Image

6) Showing the 240V mains supply and false battery. Note the bullet connectors on the interconnections.
Image

7) Showing the 12V to 3.7V adaptor and the Car Cigar Lighter socket adaptor lead. Note voltage selector switch removed and blanked off.
Image

8) Showing the 240V mains adaptor from above. Note voltage selector switch removed and blanked off.
Image

--------------

Hope this helps, any questions please feel free to ask and I'll see if I can help you.
Cheers
Andy
:P
http://www.youtube.com/comedyhunter
http://www.vimeo.com/comedyhunter
http://www.derbyphotos.co.uk/


Tue Jul 08, 2008 9:34 am
Profile
User avatar

Joined: Fri Jun 13, 2008 5:54 am
Posts: 611
Location: Oslo, Norway
Post Re: My solution to the power problem - 12V and 3.7V supplies
Congratulation, another decent Mc Gyverism!

Two questions: Do you know what the middle contact of the canon batteries is for?
How waterproof is your setup? Can you leave it outside for a night, even if there is thaw in the morning?

_________________
Canon 400D, 50D, 5D Mk II. Canon L 16-35/f2.8, Sigma 10-20. Adobe Creative Suite 4.
website:
http://www.magictimelapse.ch/en


Wed Jul 09, 2008 3:17 am
Profile
User avatar

Joined: Wed May 21, 2008 3:34 am
Posts: 45
Post Re: My solution to the power problem - 12V and 3.7V supplies
Michael wrote:
Congratulation, another decent Mc Gyverism!
Two questions: Do you know what the middle contact of the canon batteries is for?
How waterproof is your setup? Can you leave it outside for a night, even if there is thaw in the morning?


The middle contact labelled "T" I guess is connected to a thermister inside the battery pack which the charger uses to keep and eye on the termperature duing charging. You don't need to use this pin when powering the camera so it must be for charging.

Making my setup waterproof was not an important factor for me as I would never use my camera in wet conditions anyway.
But it would be quite simple to use a waterproof box with rubber seals like these..
http://www.maplin.co.uk/Module.aspx?Mod ... &U=strat15

You could then also use waterproof connections.

Andy


Wed Jul 09, 2008 9:33 pm
Profile
Site Admin
User avatar

Joined: Thu Mar 27, 2008 2:15 pm
Posts: 1696
Post Re: My solution to the power problem - 12V and 3.7V supplies
I love to see posts like this. that wooden battery is classic. :)

My setup is pretty similar to yours right now, but instead of XLRs I'm using cigarette male and female plugs. they are bulky, but they seem solid.


Thu Jul 10, 2008 8:47 am
Profile
User avatar

Joined: Wed May 21, 2008 3:34 am
Posts: 45
Post Re: My solution to the power problem - 12V and 3.7V supplies
timescapes wrote:
I love to see posts like this. that wooden battery is classic. :)


glad you liked my fake battery idea :D
It seemed the obvious thing to use as I had an offcut of pine that was about the right size.


Tue Jul 22, 2008 11:00 am
Profile
User avatar

Joined: Fri Jul 04, 2008 12:48 pm
Posts: 201
Location: Miles City, Montana
Post Re: My solution to the power problem - 12V and 3.7V supplies
Very impressive and streamlined in my opinion. For some t-l projects, I use a Nikon Coolpix setup with Digisnap controller and power controller (http://www.harbortronics.com/detail.php?id=45). This is a pretty similar setup although much less bomb proof. I've shared this equipment with a friend doing nature documentaries and things have gotten broken, bent, and even had a short while carry all the equipment in the plastic sweater box with the battern inside and not covering the terminals. Amazingly, most of the demage was cosmetic.

My setup doesn't include a panning head (something I'm seriously thinking about). My two main complaints are that the equipment seems sort of fragile and I end up with cords running all over the place.

Regarding having a weatherized system, if you have the $ then you may want to invest in one of these- http://www.harbortronics.com/detail.php?id=54 Note, that they'll sell it in parts so you can get the price to come down. A good DIYer could probably at least make the box portion with some sort of a mount internal. Ideally, I think the front should be clear plastic/glass and not be the door. Instead, the rear should be the hinged opening so that you actually can take a few test pictures and check them on the LCD before starting the t-l. I suppose some cameras have a swinging LCD that could be positioned forward to check pictures... Also, I think that their 360 table turner has a glass dome option... Again, if you have the $ you can buy yourself a soln.

_________________
http://vimeo.com/user1477834/videos
Canon, Arduino, AE, etc.


Sun Sep 07, 2008 9:10 am
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © phpBB Group.
Designed by Vjacheslav Trushkin for Free Forums/DivisionCore. pozycjonowanie