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Auto on-off management

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Offline ahull

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Re: Auto on-off management
« Reply #20 on: 11 / May / 2013, 19:04:47 »
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One more idea, these cameras contain the RX-4574LC Epson manufactured real time clock chip.

According to the datasheet and the application notes, (EDIT:  Updated link, Epson link was a little flakey) as well as being the source of the real time clock in the Ixus, it has two pins (pin 3 & 4) which can be used as output for a timer and an alarm. These two pins are open collector, and appear to be active low i.e. Normally High, gong Low when the timer or alarm time event occurs.

If the package of this chip permits us to access these two pins, i.e. it is possible for a human being with a steady hand to solder wires to them,  then we would be part way to giving the camera the ability to wake up from practically zero current consumption, take a photo (or do whatever else we decide using CHDK) and then go back to sleep.

Leaving aside the microsurgery we would need to solve two other problems.

First we would need to use the open drain output to trigger the DC power controller to switch the camera on. 

Second we would need to be able to program the RTC chip alarm and/or timer registers.
« Last Edit: 12 / May / 2013, 09:41:06 by ahull »

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Offline ahull

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Re: Auto on-off management
« Reply #21 on: 13 / May / 2013, 22:04:14 »
The power controller IC looks to be  a variant of this presumably a 3 channel variant.

However the interesting thing I take from the datasheet is that the CTRL pins which we need to interface to, can take an input between -0.3V and +13.5V, so we don't need any signal conditioning over and above the diode, who's function is to avoid us connecting the external control input to camera +V BAT, if we tried to operate the power switch at the same time as the external control.



« Last Edit: 15 / May / 2013, 17:21:35 by ahull »

Re: Auto on-off management
« Reply #22 on: 15 / May / 2013, 04:58:47 »
It will be interesting to see how this works out.

In the meantime, I will modify an A620 and will post a photo of the very discrete change.


David

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Offline ahull

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Re: Auto on-off management
« Reply #23 on: 15 / May / 2013, 16:35:29 »
I have just had a chance to analyze the Ixus 60 schematic (I have a couple of ebay Ixus 60s and even a spare Ixus 60 motherboard, so I can afford some collateral damage when I get a chance to try this).

The modification I intend to try is very simple. I am going to put a link wire between pin 4 (USB ID) on the USB connector (on the top side of the motherboard), and test point FP1002 (on the reverse side of the motherboard), which is connected to SW_POWER, the signal from the power button (which is routed from the user controls FPC via the DC controller PCB to the motherboard). This is by far and away the simplest mod, as it is all on the one board.

Test point FP1002 looks easy to locate, relatively large and therefore should be easy to solder a connection to. PIn 4 on the  motherboard USB connector looks a little more of a challenge. Routing the mod wire from the front to the back of the board looks the easiest part. A couple of strategically placed small bits of insulating tape should secure and protect it. 

I will put the diode, needed to OR this signal with the external input, in my modified USB cable, this will allow me to experiment with different arrangements of components without having to break open the camera again. 

I have even sourced a suitable USB connector (from the connector set of a cheap phone charger for the car) which has pins 1,4 and 5 populated, all in a very neat tiny case which can be opened up, modified and re-uesd. All I need now is the time to actually strip one of the cameras, and fix the mod wire.

This should give me an absolutely stock looking Ixus 60 with the magic ability to be switched on and off via a special cable attached to the USB port (the same magic cable will also be modded to be used to trigger the shutter via CHDK).

Photos of the build will follow, as and when I get the time to try it. 

If this works, I may even try the mod to the RTC chip (I think a surface mount CMOS 4069 (wired dead bug style) would be sufficiently low power to use as 3.3v logic inverter to provide the necessary +3v3 to switch on the camera from the /alarm or /timer signal).

This bit of surgery, however looks a little more tricky. The RTC chip package and the CD4069BE are pretty darned small, and thus tricky to solder. The RTC chip (IC1002 in the Ixus diagram) is however conveniently close to, and on the same side of the board as, test point FP1002.

I would also need to write a bit of code to program the alarm and/or timer registers (based on the code that the Ixus 60 uses to set the time no doubt).   More of a long term project I think.
« Last Edit: 15 / May / 2013, 17:32:11 by ahull »


Re: Auto on-off management
« Reply #24 on: 17 / May / 2013, 08:22:53 »
This should give me an absolutely stock looking Ixus 60 ......
More of a long term project I think.

Well, below is a photo of an A620 that I have just modified.
The rest is mere detail .....

A radio control receiver output, microcontroller or commercial device can simply be connected to the two golden sockets.


David

Re: Auto on-off management
« Reply #25 on: 17 / May / 2013, 08:33:41 »
Well, below is a photo of an A620 that I have just modified.
This forum doesn't have a "Like" option so I'll just post to say "Good job!".  Given me some ideas too.
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Auto on-off management
« Reply #26 on: 17 / May / 2013, 09:14:00 »
Just a reminder ... no matter how skilled you are working on a new camera can present unknown pitfalls.

You have to be prepared to lose.


Re: Auto on-off management
« Reply #27 on: 17 / May / 2013, 11:09:56 »
Just a reminder ... no matter how skilled you are working on a new camera can present unknown pitfalls.
You have to be prepared to lose.
I have a collection of very small nylon gears and assorted tiny springs & washers left over from attempts to fix "lens errors" on several Nikon P&S cameras.  My success rate there has been about 50% so I know exactly what you mean about the surprises when you open a new camera - especially the lower cost ones.
Ported :   A1200    SD940   G10    Powershot N    G16


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Offline ahull

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Re: Auto on-off management
« Reply #28 on: 17 / May / 2013, 17:43:29 »
Well, below is a photo of an A620 that I have just modified.
The rest is mere detail .....

 :D Very neat, and no doubt a tad easier to solder then my proposed Ixus 60 mod.

One detail I would like however...  are those socket pins extracted from something like this by any chance? 

I presume wires from the inside ends of the two pins are attached to either side of the power switch. This would allow any device with switched contacts to power up the camera.

If you had a third pin attached to ground, and knew what voltage the camera expects to appear on one of those other two pins, you could also fire an input direct from a PIR module or microntroller without the need of a relay.  A PIR module typically consumes a few microamps, and would be great for triggering a wildlife camera.

I think I might have to drill a couple of holes in to my A560 and experiment with that too. The Ixus 60 hasn't quite made it to the surgical ward yet, unfortunately other work keeps getting in the way.

Oh, and the warning about having a few failures along... that sounds pretty familiar. I too have a couple of lens units that wont be taking any more pictures, but since my budget for Ixus's (or should that be Ixusi?) is "under a fiver or I'm not interested", failures are not too painful.
« Last Edit: 17 / May / 2013, 17:47:45 by ahull »

Re: Auto on-off management
« Reply #29 on: 17 / May / 2013, 18:34:58 »
no doubt a tad easier to solder then my proposed Ixus 60 mod.
Yes, but the surface-mount dome switch is on a flexible printed circuit so you have to be careful and quick and also use wire thinner than normally available.

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One detail I would like however...  are those socket pins extracted from something like this by any chance?

In this instance no, but that is what I often use.
Postage is rather excessive for such small items.
If you use a 'razor saw', you can cut-off two pins to use as a plug.
Ideally, you need a set of precision micro drills so that you get one that will allow a tight fit.
Be very quick with the soldering or the plastic will melt. 

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I presume wires from the inside ends of the two pins are attached to either side of the power switch. This would allow any device with switched contacts to power up the camera.

Exactly.

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If you had a third pin attached to ground, and knew what voltage the camera expects to appear on one of those other two pins, you could also fire an input direct from a PIR module or microntroller without the need of a relay.

You may not need a third pin, one of the sockets may be connected to ground.

OK, I have just measured it.
Across the pins the voltage is 5.5 volts.
When the power button is pressed it is pulled to ground so any device capable of doing that will be suitable.

(annoyingly, I have ground on the top terminal, I will note that for future cameras).

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you could also fire an input direct from a PIR module or microntroller without the need of a relay.

Except each time the PIR triggers the camera will be turned on or off.

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I think I might have to drill a couple of holes in to my A560
Do not assume plastic is non-conductive, the top of the A620 is 'very' conductive.
« Last Edit: 17 / May / 2013, 18:52:22 by Microfunguy »

 

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