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Auto on-off management

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Re: Auto on-off management
« Reply #10 on: 09 / May / 2013, 14:02:10 »
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I thanks everyone for the effort in helping me, I am reluctantly starting to consider seriouosly to make the client buy a game/thropy cam...it should solve the problem with battery life and some of them goes as up as 8MP, which might not be bad at all for a timelapse on the website. well, I'll see if no other solution comes up  :blink:

Re: Auto on-off management
« Reply #11 on: 09 / May / 2013, 14:07:13 »

Re: Auto on-off management
« Reply #12 on: 09 / May / 2013, 14:11:48 »

May I ask you what kind of battery are you using?

A 6V 12 amp-hour sealed lead-acid battery with 'tag' terminals.

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S95 price range might be ok
Just for the record, I am using my A620's for timelapse, not the S95's.

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I hope to find something even cheaper for 7MP, so I'll have a look about it.

When you do, we can tell you if the screen can be turned off.


David

Ported :   A1200    SD940   G10    Powershot N    G16


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Offline ahull

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Re: Auto on-off management
« Reply #14 on: 10 / May / 2013, 12:00:44 »
Just spotted something in the Ixus 65 schematic... Pin 4 (USB -ID) on the USB connector is .... not connected... (can you see where I am going with this...)

Furthermore according to the same schematic to switch on the Ixus 65, you need to apply VBAT to pin 38 of IC601 SW REG CONTROL MB39C303PVK-G-EFE which is conveniently broken out on test pin CP604

.... so ... all you need to do with the Ixus 65 is connect a diode between pin 4 on the usb connector on the motherboard and CP604 in the test pads, and apply a 3.7V pulse  between Pin 5 (GND) and pin 4 (USB ID) of the USB connector and the Ixus 65 will switch on, apply another pulse and it will switch off and so on.

Only trouble is.... I don't have an Ixus 65 to test this idea.  :(

.... however the same power management controller is used in the following cameras (and possibly others)..

Component name in database: MB39C303

Component type: Power manager, PWM controller

Used in: Canon Ixus 60; Canon PC1193; IXY Digital 70; PowerShot SD600; Canon Ixus 65; Canon PC1147; PowerShot SD630; IXY Digital 80; Canon Ixus 800; Canon PC1176; IXY Digital 800 IS; PowerShot SD700 IS; Canon Ixus 850; IXY Digital 900 IS; PowerShot SD800 IS; Canon PC1209; Canon Ixus 900; IXY Digital 1000; Canon PC1206; Digital IXUS 900Ti; PowerShot SD900; Canon Ixus 950; IXY Digital 810 IS; PowerShot SD850 IS; Canon PC1235; Canon Ixus i5; Canon TX1;

.. so for these cameras at least, a diode between USB pin 4 and MB39C303 pin 38, and a USB lead to our external control device may be all we need.
« Last Edit: 10 / May / 2013, 12:18:09 by ahull »

Re: Auto on-off management
« Reply #15 on: 10 / May / 2013, 14:08:42 »
Only trouble is.... I don't have an Ixus 65 to test this idea.  :(

Buy one, test the idea, sell it !

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Offline ahull

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Re: Auto on-off management
« Reply #16 on: 10 / May / 2013, 14:54:16 »
Only trouble is.... I don't have an Ixus 65 to test this idea.  :(

Buy one, test the idea, sell it !

I do however have an Ixus 60, and an even better idea (its amazing what you can dream up while walking the dog)...

If I use TWO diodes, one of which already exists on the board,  our input becomes +5V tolerant, since a +5V signal will drop by the forward voltage drop of the diode, typically 1.2V... so we drop our +5v to 3.8V. which in my book is close enough to 3.7V (the actual stated battery voltage of an Ixus is 3.7V, but fully charged, it will be slightly more). I suspect the difference of 0.1V will be of no consequence. 

Better yet since in this setup I wire a single diode between the USB ID pin (using the diode anode) and the opposite side of the power switch to +V Batt. (using the diode cathode) this has two advantages. First, according to the Ixus 65 schematic  this signal goes to an existing diode first, and through that to the pin on the power controller chip, (hence as explained above I only need this one more diode drop of 1.2V to make my input  +5V tolerant).

The second advantage is that this pin would be easier to find, and larger, and thus easier to solder to than one of the pins on the voltage controller chip.

To find out which side of the switch to connect the cathode of the diode to, I can either look at the diagram (page 10, Operations FPC Assy. for example), or for cameras where the diagram is not available, I can check for continuity (zero ohms) between one of the "Power On" switch pins and the + terminal in the battery box with the battery removed. If we don't see this continuity, we can assume that the model in question uses a different method of detecting the  "Power on" switch (labeled in the case of the Ixus 65, the SW_POWER signal).

I need to consider one more factor,  there is likely to be an existing signal on USB ID from the host. Therefore if we connect a usb lead between the camera and our PC, we  need to ensure this mod is not going to stop us from being able to use the camera as before...

If we consider the USB spec...

Pin    Name    Cable color    Description
1    VBUS    Red    +5 V
2    Dāˆ’    White    Data āˆ’
3    D+    Green    Data +
4    ID    None    Permits distinction of host connection from slave connection
ā€¢ host: connected to Signal ground
ā€¢ slave: not connected
5    GND    Black    Signal ground

... so at worst we will have the diode anode grounded, which should be of no consequence....

Ladies and gentlemen I think I will need to find time soon  to break out the soldering iron and the magnifying glass.  :D

(Unless anybody else is up for the challenge).
« Last Edit: 10 / May / 2013, 15:40:19 by ahull »

Re: Auto on-off management
« Reply #17 on: 10 / May / 2013, 17:13:16 »
I currently have five A620's and do not intend to ever sell them so I am not bothered about my (very discrete) modification being visible.

Incidentally, 1.2 volts is a large voltage drop for a diode, 0.6V is more normal.

Remember, even that voltage drop requires a 'reasonable' amount of current to flow, probably more than in your application.

So, the voltage drop could be less than 0.6 volts.


David


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Offline ahull

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Re: Auto on-off management
« Reply #18 on: 11 / May / 2013, 04:02:07 »
I currently have five A620's and do not intend to ever sell them so I am not bothered about my (very discrete) modification being visible.

The A620 has the advantage of having a little more space inside and a plastic case, so surgery is a little easier,

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Incidentally, 1.2 volts is a large voltage drop for a diode, 0.6V is more normal.

Remember, even that voltage drop requires a 'reasonable' amount of current to flow, probably more than in your application.

So, the voltage drop could be less than 0.6 volts.


Good point, I might need two or three diodes in series and probably a current limiting resistor. My gut feeling is that the extra diodes are probably unnecessary, I probably only need the one, bearing in mind that for my initial testing I can condition the signal at the other end of my modified usb lead. I will just need to find out by experiment. I have a couple of "lens error" cadavers I can practice on.

More importantly I will need to check that pin 4 of the USB connector is actually populated. This is the most important bit of the puzzle, as it opens up the possibility of doing this kind of mod to pretty much any camera, the only thing that will vary from model to model is the nature of the input needed to power on the camera, and where we route that input to. For some we may need to pull the signal low for a short period, for others like the Ixus it needs to be set high for a brief pulse.
« Last Edit: 11 / May / 2013, 04:28:50 by ahull »

Re: Auto on-off management
« Reply #19 on: 11 / May / 2013, 07:05:37 »
It is not elegant but you can use a miniature electromechanical device to press the shutter button, such as a solenoid (linear or rotary) or servo.

No modifications to the camera whatever.

You can store the required charge on a capacitor until it is needed (in the case of a solenoid).
That will allow a high peak current to flow.

Here is a suitable product from the US of A  :-

http://www.goldmine-elec-products.com/prodinfo.asp?number=G18567
« Last Edit: 11 / May / 2013, 07:10:46 by Microfunguy »

 

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