Auto on-off management - General Discussion and Assistance - CHDK Forum

Auto on-off management

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Auto on-off management
« on: 08 / May / 2013, 11:33:39 »
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Hi, I have searched throught the forum but I wasn't able to find an answer so here I am.

I will shoot a bulding site timelapse. I think I will go with the solution suggested here http://goprouser.freeforums.org/long-time-lapse-with-copying-files-and-external-power-t3496.html#p20545 .

I will set the camera (as suggested on that post I think I will go for a cheap Powershot) to shot 1 picture everty 10 mins.
I need to make the batteries last for as long as possible, so it would be perfect to make the camera shut down between two shots, hoping it will make the batteries last at least three days or so.

Question is: is there any script to make the camera act like that? (shot/turn-off for 10 min./shot/etc.)
I am sorry if the question had already been answered but as I said I wasn't able to find it anywhere.
Thanks in advance to whom will help me

Re: Auto on-off management
« Reply #1 on: 08 / May / 2013, 12:16:23 »
I will set the camera (as suggested on that post I think I will go for a cheap Powershot) to shot 1 picture everty 10 mins.  I need to make the batteries last for as long as possible, so it would be perfect to make the camera shut down between two shots, hoping it will make the batteries last at least three days or so.
The problem you are going to have is that while a script can shut the camera down,  there is no way for the script to turn itself back on once it's turned off.

There is a forum thread on other power saving methods :
http://chdk.setepontos.com/index.php?topic=9049.0
but you will be hard pressed to get a couple of days from any internal battery.

I've been working on an intevalometer script designed to run for months at a time.   But that requires an external power source - either a really big battery and a switching power supply or a power source that draws from the electrical mains.   If you'd like to help test,  I can share with you prior to my completing the documentation.

Ported :   A1200    SD940   G10    Powershot N    G16

Re: Auto on-off management
« Reply #2 on: 08 / May / 2013, 15:13:47 »
Hi, I have searched throught the forum but I wasn't able to find an answer so here I am.

I will shoot a bulding site timelapse.
I need to make the batteries last for as long as possible, so it would be perfect to make the camera shut down between two shots, hoping it will make the batteries last at least three days or so.

Thanks in advance to whom will help me

Let us say a camera consumes 100mA with screen off or backlight off depending on the camera model.
If the camera uses 1000mAH batteries , they will run-out after ten hours.
If they use 2500mA batteries they will run-out after 25 hours.

I currently have three camera timelapse rigs setup in woodland.
They are powered by an external battery and a simple script turns off the LCD screen and restricts shooting to every five minutes from 8 am to 4 pm.
I change the batteries every five days.
Even though I designed the circuitry to allow 'hot swapping' of a fresh battery I now prefer to turn the camera off first.
I can then check it is still capturing images.
(an led should flash every 30 seconds if it is but that does not seem to be working).
Besides, who knows how the Canon firmware will react if you leave the camera on for weeks or months ?

My A620 consume 260mA normally, 60mA with screen off.
My S95 consumes 380mA normally, 100 mA with screen backlight off (you cannot turn the screen off).
I would go for a camera that allows the screen to be turned off.

My next step is to modify the cameras so that they can be turned on for just eight hours per day.
That should triple battery life.

David
« Last Edit: 08 / May / 2013, 15:33:10 by Microfunguy »

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Offline ahull

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Re: Auto on-off management
« Reply #3 on: 08 / May / 2013, 16:10:37 »
I have been considering a couple of methods to achieve this without hacking the camera about too much.

One idea I had was to use the USB connector to power on the camera.

This is what I considered.. When you attach the USB lead you ensure that 0v (Pin5) and +5V (Pin1) are connected on the camera mini usb connector. I was considering attaching  a specially modified USB cable to the USB port to allow us to actually control power on/off to the camera. This would mean that externally the camera would appear unmodified, but would power on when the USB lead was attached. The idea being that switching the +5V on and off on the USB pin would have the same effect as pressing the power button on the camera.

Initially there would be no signal on pin1, but when this pin is enabled,  (using a PIR sensor, low power micro-controller, reed relay, or whatever method is appropriate) an internal modification to the camera passes this signal through a small capacitor or diode to the "Power button" pin of the camera, thus simulating pressing the power button. If this was capacitively coupled, then in theory, the input would only last for a short duration, and thus once the camera came on, we could still power off the camera with the power button. The exact circuit needed to make this work would need to be determined by experiment.

The external signal would need to be either capacitively coupled or use a diode to OR the power button with the external power on signal source, or a transistor or inverter to give us a low from signal if that is what was required when we get a high (+5v) from the USB pin (which of these methods works would have to be determined by experiment, and would depend on whether we trigger on logic low or logic high, and may in fact vary from one model of camera to another).

It may be necessary to level shift this signal with a couple of resistors.

Anybody have any  thoughts about this idea?

   
« Last Edit: 09 / May / 2013, 09:26:00 by ahull »


Re: Auto on-off management
« Reply #4 on: 08 / May / 2013, 16:53:21 »
Anybody have any  thoughts about this idea?

Unless I am missing something, why not just make a two-pin socket in parallel with the shutter button ?

There is a good chance one of the contacts is connected to ground and if so, just pull the other contact to ground with a microcontroller or similar device .

If not, use interface with a 5V DIL relay.



David
« Last Edit: 08 / May / 2013, 20:09:19 by Microfunguy »

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Offline ahull

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Re: Auto on-off management
« Reply #5 on: 09 / May / 2013, 08:40:37 »
Anybody have any  thoughts about this idea?

Unless I am missing something, why not just make a two-pin socket in parallel with the shutter button ?

There is a good chance one of the contacts is connected to ground and if so, just pull the other contact to ground with a microcontroller or similar device .

If not, use interface with a 5V DIL relay.



David

I was thinking of a mod that doesn't require me to drill holes on the camera or have a socket dangling on wires.

The mod I describe would all be entirely internal to the camera, and the only evidence of its existence would be the fact that the camera would power on when the USB lead was connected (as many other cameras already do).

If I used smd components I should be able to fit the whole mod in a few cubic mm of space, so it could be easily hidden in the camera. Think wire from USB +5V pin on camera motherboard PCB, to small "black blob" in heat-shrink tubing, from there, wire to 0v on motherboard PCB, wire to camera "on" button pad on button PCB or same signal pin on motherboard PCB, all hidden internally. Result - warranty void  8)

I suspect an opto-isolator might be a safer bet for the "black blob", that way we are protected from the possibility of firing a great deal more than +5v into the pins on the Digic. However if we don't care about this too much, then depending on whether we need logic low or high on the "power on" switch signal pin, a pair of resistors to change the logic level from 5V to 3.3v and possibly a transistor as an inverter might be all we require.
« Last Edit: 09 / May / 2013, 09:17:34 by ahull »

Re: Auto on-off management
« Reply #6 on: 09 / May / 2013, 11:55:18 »
What if you want to use the USB remote switch ?

Incidentally, I have only seen the circuit diagram for one camera and the USB V+ signal is routed to the DIGIC via a pair off transistors.
In that case and presumably others, the USB voltage specification is irrelevant, it does not have to be 5V.


Re: Auto on-off management
« Reply #7 on: 09 / May / 2013, 13:32:11 »

I currently have three camera timelapse rigs setup in woodland.
They are powered by an external battery and a simple script turns off the LCD screen and restricts shooting to every five minutes from 8 am to 4 pm.
I change the batteries every five days.

David

That would be good enough for me, five days would be perfect, I think I might even go back and forth every once in a while to check if shooting is ok, so no problem at all.
May I ask you what kind of battery are you using? Is it a 12V/24V with pluggable socket or just a commercial camera battery?
S95 price range might be ok but I hope to find something even cheaper for 7MP, so I'll have a look about it.


Re: Auto on-off management
« Reply #8 on: 09 / May / 2013, 13:35:15 »

I've been working on an intevalometer script designed to run for months at a time.   But that requires an external power source - either a really big battery and a switching power supply or a power source that draws from the electrical mains.   If you'd like to help test,  I can share with you prior to my completing the documentation.

Thanks, the problem with being on a construction site is that I they will almost cetainly run on power generator, and they will shut it down once the sun is down.

Re: Auto on-off management
« Reply #9 on: 09 / May / 2013, 13:44:03 »
Thanks, the problem with being on a construction site is that I they will almost cetainly run on power generator, and they will shut it down once the sun is down.
Might be more work/cost than you want to take on,  but modifying Microfunguy's battery suggestion to use a small battery charger permanently connected to the battery would allow the system to recharge every day with there was power available.
Ported :   A1200    SD940   G10    Powershot N    G16

 

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