Wiring - Camera trigger A490 - USB - Jack

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Wiring - Camera trigger A490 - USB - Jack

Post by Minimalizer »

Hi, I'd like to know if someone has plan to wire a usb trigger to a A490 Powershot
(although in another tutorial, Tom Horsley says it only works for A480 powershot, here:
http://home.comcast.net/~tomhorsley/har ... %20Trigger
After some web searches, it became apparent that there is really only one model camera supported by SDM that you can easily buy: The PowerShot A480

If anyone has a A490 working trigger, could you please confirm that it is possible and indicate the plans of the wiring?
A simple sketch of the wiring will do (since I just need to know where to solder what).

I was also wondering if I could use the jack without any power instead of the powered mini usb...

EDIT: I found the answer here: http://chdk.wikia.com/wiki/USB_Remote_Cable with a plan and details about CHDK.
Apparently, the jack cannot be used. Only the mini USB.

EDIT#2: I'm discovering that A490 Firmware 100 E may not be supported by the CHDK software.
Could anyone confirm wether or not it works?
It's tough not knowing if my camera can be triggered via a remote or not.
If i can't make it electronically, i'll make it mechanically with a bike brake cable or highjacking the button itself... (but i need to know if i'm losing my time, cheers!)
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Re: Wiring - Camera trigger A490 - USB - Jack

Post by dpc »

I'm in the same boat as you, but with A495 cameras. There's an alpha version of CHDK for the A495, provided you know which version of the firmware is on your camera. I didn't even try it because I don't want to be tied down to Canon cameras, and from past experience "alpha" is usually another term for "endless headaches".

So, I completely tore apart one of my 495s over the last week trying to get to the shutter button switch and determined that it's not worth the trouble. The switches are on a flat flex cable membrane and there's nothing to solder to. I looked at getting a flex cable connector breakout board but that was a dead end.

I'm now going with a mechanical shutter trigger. I'm not a fan of the brake cable system so I'm going with push-type solenoids and a rubber isolator to keep from destroying the camera button. I'm planning to machine a camera mount from a block of MDF for my A495s so it should be fairly clean and sturdy. It's a work in progress but in the end it's a simple single pole switch to trigger both cameras and doesn't tie me down to Canon (CHDK) cameras. I could always throw a relay in there later and control the cameras from a USB or RS232 port of my PC.

Re: Wiring - Camera trigger A490 - USB - Jack

Post by freemab »

The information about which cameras can or cannot be electronically triggered seems incomplete . I have a Canon Powershot A590IS (which I got because somewhere on this site it is recommended specifically because it can be electronically triggered), and at first I could not find the info about triggering it. However, it is possible to trigger it with an appropriate remote, and this page - http://www.stereomaker.net/eng/sdm/quick.htm - tells you more about that. (Scroll about 2/3 to 3/4 the way down the page to the title, "Preparing your switch unit and checking the batteries".)

In my case, I used SDM, rather than CHDK that it's based upon, as the control software for the camera. I suggest you use an SDHC card no larger than 4GB, as that can be formatted as one partition, whereas larger cards must be partitioned, which seems to be a headache. (I have yet to succeed with a 32GB SDHC card).

My switch works, but all is not quite well. I have yet to master SDM, largely because I am having difficulty plowing through the available information on it. However, the switch DOES work, so here's a description of my remote shutter trigger switch:

My switch provides 4.5V pulse. It was made from a 3-AAA-battery mini flashlight (http://www.harborfreight.com/3-1-2-half ... 97036.html). I pressed the lens and LED's out and used that end for the USB cord (with mini plug that fits the camera on the other end).

A "fender" washer, of diameter slightly smaller than the ID of the flashlight body, holds a grommet, and a 1/4" diameter brass screw is inserted through the grommet such that on the head will contact the battery pack. The other end it is connected to the red lead of the USB cord by means of a 1/4" crimp lug, secured to the screw with a nut. (The battery pack must be inserted with the positive end against this contact. This has been indicated on the battery pack itself.)

The fender washer is drilled for a small sheet-metal screw, which in turn secures a small lug crimped to the black lead of the USB cable. The fencer washer makes contact with the aluminum flashlight housing, but to ensure against failure, I ran a screw into it through the flashlight body. I knotted the cord close in, then potted the knot, etc., in hot-melt adhesive.

The original switch on this flashlight is a pushbutton "toggle" switch which doesn't suit the purpose. Unfortunately, its design precluded easy conversion to a pulse pushbutton. After futile attempts to convert it, I replaced its guts with one of these mini pushbuttons: http://www.sparkfun.com/products/97 .

The contacts from this I soldered to the corresponding contacts from the original "toggle" switch, using very short copper leads. I used drops of hot melt adhesive to secure this switch and leads to the body of the original switch, as well as for electrical insulation. This modified switch mounts neatly in the modified outer half (i.e., nearer the button) of the original switch body (using pieces of the original push button), but the inner half could not be used as such, so pieces of it were used to secure the two original contacts, now soldered to the new switch. (Hot-melt glue would have worked as well.) A clearer description I can't really provide. The basic idea was to use the new switch in the old housing, and anything that accomplishes that will work.

This modified switch pressed back into the the original housing it came from, resulting in a pushbutton switch end that superficially looks unchanged from the original, and screws in just as the original switch did, making contact with the original spring to the negative end of the battery pack with one lead and to the aluminum flashlight case with the other.

Before using this switch, I tested it with a voltmeter.

As I said, my current problems are not with the switch but with the SDM software. I'm in the process of seeking answers for those.
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