Using USB shutter release via OTG on SX530HS

Jez

3

Using USB shutter release via OTG on SX530HS

« on: 01 / February / 2017, 07:11:22 »

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So I've been using CHDK on my SX530 for a little while, first got into it to remove the dark-frame subtraction so that I could do some fireworks shooting (ain't nobody got time to wait the length of the exposure again after every shot), and would now like to use the USB shutter release function so that I can work a bit more stably with my tripod. The seemingly obvious answer for me to do this without getting a soldering iron out would be to use an OTG cable with my Android phone to send a signal into the USB port - but so far, this seems easier said than done (and unfortunately the official Canon app is laughably bad as it's stuck in auto, else I wouldn't be bothering with this).

The phone is a Galaxy S4, and it fully recognises the camera if I plug it in via the cable... The problem being that when they are tethered, the camera seems to send a signal saying "hello, I am a camera, I'm going to go to sleep now", goes to the Playback screen and locks all the controls. I installed an app called Remote Release, which is meant for triggering EOS cameras via OTG. When the camera's connected the app recognises that it's there and reports the version correctly... but because it's stuck in playback mode, it can't shoot anything.

If I go into CHDK and set up the remote shooting options before plugging in the cable, it no longer locks the camera into playback mode - but the phone also no longer acknowledges that the camera is connected at all. So ideally what I need is something that gets the camera to send the "hello, I am a camera" signal without going to sleep, OR something that allows the phone to send a signal via the USB without knowing that there's a camera there. Is there any way of doing this?

« Last Edit: 01 / February / 2017, 09:12:06 by Jez »

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waterwingz

12138

Re: Using USB shutter release via OTG on SX530HS

« Reply #1 on: 01 / February / 2017, 08:32:08 »

The CHDK USB remote function works by watching for power to be applied in the +5V pin of the camera's USB connector. It's described here : CHDK USB Remote and does not do what you are expecting.

Obviously, that's not what you want to do as you are looking for some sort of communication between your phone and camera over USB (via an OTG cable so that the phone can be a "host"). Unfortunately, while the code exists on the CHDK side to support this, AFAIK there is no Android or iOS app that supports it on the camera side for the PTP implementation provided by CHDK.

So perhaps your best option is to build a simple USB remote "cable release". There are several links in the wiki page I posted that describe different ways to do that - including wirelessly.

Update : I fixed your link : Remote Release. Nice looking app but it obviously was not written to work with CHDK.

« Last Edit: 01 / February / 2017, 08:36:28 by waterwingz »

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Ported : A1200 SD940 G10 Powershot N G16

Jez

3

Re: Using USB shutter release via OTG on SX530HS

« Reply #2 on: 01 / February / 2017, 09:15:19 »

I think perhaps I explained wrongly - the idea is that I'd like to bypass having to build one of those releases as I don't have easy access to soldering equipment - I thought that this might be possible using materials I already have by having the phone send that signal to the pin. Actually communicating between the phone and the camera isn't at all necessary for me, the main point is just that the phone is something powered that I can connect to the USB port via the OTG cable. All I'd need is something on the phone that allows me to send something via that pin, if such a thing exists.

(and oops on the broken link - afraid my BBCode is a little rusty these days...)

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waterwingz

12138

Using USB shutter release via OTG on SX530HS

« Reply #3 on: 01 / February / 2017, 09:28:04 »

Quote from: Jez on 01 / February / 2017, 09:15:19

I think perhaps I explained wrongly - the idea is that I'd like to bypass having to build one of those releases as I don't have easy access to soldering equipment - I thought that this might be possible using materials I already have by having the phone send that signal to the pin.

Understood. One "sneaky" way to do this with no soldering is to use one of those external cellphone battery packs. You can pick them up for a few bucks online and the cheapest one you can find will work perfectly. Use a standard USB cable to connect it to the camera's USB jack. When you configure CHDK in USB Remote mode, it will take a shot each time you plug the cable into the power pack (obviously you leave the camera end attached all the time while doing this).

Quote

Actually communicating between the phone and the camera isn't at all necessary for me, the main point is just that the phone is something powered that I can connect to the USB port via the OTG cable. All I'd need is something on the phone that allows me to send something via that pin, if such a thing exists.

AFAIK, nobody has made something like that available. Sorry.

« Last Edit: 01 / February / 2017, 09:30:32 by waterwingz »

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Ported : A1200 SD940 G10 Powershot N G16

Jez

3

Re: Using USB shutter release via OTG on SX530HS

« Reply #4 on: 01 / February / 2017, 10:56:59 »

Thanks for the advice. Actually it seems to have solved my problem, though maybe not in the intended way - it seems as though plugging and unplugging the cable to the phone while CHDK is in remote mode actually has the same effect as the power pack option you suggested (based on the way it's reacting it seems to act as though there's one pulse on plugging in, and two on unplugging). Not the most elegant perhaps, but at least for now it should be workable.

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Hardware_Hacker

322

Re: Using USB shutter release via OTG on SX530HS

« Reply #5 on: 01 / February / 2017, 19:12:32 »

Quote from: Jez on 01 / February / 2017, 10:56:59

... Actually it seems to have solved my problem, though maybe not in the intended way - it seems as though plugging and unplugging the cable to the phone while CHDK is in remote mode actually has the same effect as the power pack option you suggested...

On my Nexus 7 I can connect a 4-port USB-2 Hub via a OTG adapter a USB mouse and a Portable USB-2 keyboard.
The Nexus 7 then powers the USB-2 Hub via the OTG adapter.
So there are still two free USB-2 ports for use with CHDK cameras.
My 4-Port USB Hub has an small external power connector which could be modified, internally, as per Option #1.

Option #1:-
Would be to internally modify the, spare ports, USB-2 Hub. If you have the necessary skills.
Option #2:-
Would be to use a external CHDK USB-2 switched cable on a spare hub port.
Option #3:-
Would be to use Canons Camera Connect via a Wi-Fi capable canon camera, that supports remote shooting.
you can use the mouse to click on the apps shoot button.

Unfortunately Canons Camera Connect (CCC) doesn't currently support a script interface.
It might be possible to create a very simple app that's only function is to press the (CCC) apps shoot button.

Option #4
Could be to use the TriggerTrap (TT) Mobile app, that supports a open source (OS) interface for some DSLR Canon Cameras.
It works via, a very short audio output, on the headphone jack. see here
http://www.triggertrap.com/how-to/use-a-cable-release
https://en.wikipedia.org/wiki/Triggertrap

The original open source, passive, interface that TriggerTrap provided is very basic. i.e. Version 1
I think that by adding a few more simple electronic component's it could be made to work well with CHDK.
A Quote from TT
https://triggertrap.reamaze.com/kb/triggertrap-mobile-4/what-s-the-difference-between-the-triggertrap-mobile-dongle-1-and-2
"...The differences are that version 3 is a lot more sensitive.
This makes it compatible with a lot of devices that previously weren't compatible due to volume issues.
The sensitivity will also make it a little faster on iOS devices..." (BUT Version 3 is now a Closed Source version.)
http://www.triggertrap.com/license/
http://www.diyphotography.net/building-diy-trigger-trap/
More Link's for the original OS TriggerTrap Interface To Do.

H-H

Edit #1 also see an old post here
Option #5:- Remote control Android (Reply #21 but via a TT Audio Pulse)
https://chdk.setepontos.com/index.php?topic=6823.msg72835#msg72835
« on: 06 / September / 2011

« Last Edit: 01 / February / 2017, 21:57:05 by Hardware_Hacker »

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