The DIY stuff

[Microfunguy]

A quick update ...
I have a Chinese wireless doorbell and have just found that pin 6 of the logic IC goes high when a signal is received.
Music starts and there is a four-LED light show  for a second or so.
The output signal then goes low.

I connected the 3V signal directly to my A620 and it takes three pictures in FAST mode.

In ordinary DIRECT mode, it also takes three pictures so the output on pin 6 must pulse slightly.

I will add a diode and capacitor to integrate the pulses.

It should then take a single photo when music finishes.


EDIT
------

Why use components when we can do it with software ?
Try this version with your A720 100c :  http://www.zshare.net/download/68335211e530994f/

In menu Bracketing/Overrides you can set focus-mode to manual or digiscope to enter FAST mode.

The camera triggers immediately it detects the USB signal.

It will not trigger again until a pulse is received after two seconds.
I will make the pulse lockout time a menu option.
That now works with my A620 without any additional components.


On my camera, 'USB' was displayed for most of the music duration.

[Seagull]

In the Bracketing/Override menu, set focus-mode to digiscope.
Exit ALT mode, the word FAST should be at top of screen.

In this mode the camera should trigger as soon as it detects the voltage.

Let us know how you get on.

Did that thanks.
Initially a button press on the remote resulted in two quick pictures but subsequent tests have been as expected.
i.e. a single shot for each press.

I had left the receiver on all night so I hope the lowered voltage (4.3V) has not caused the Double shot problem to go away.
 
Thanks again forthe help.
 

[Microfunguy]

I hope the lowered voltage (4.3V) has not caused the Double shot problem to go away.

Use the new software version that I posted the link for above.

[Seagull]

Hi microfunguy
Sorry not to reply sooner but I have been trying to get my head around a bit more of the detail re the various flavours of CHDK and lessen my level of ignorance of the features covered in the menus..

When I tried the latest DISKBOOT.BIN (192,772kB 11/11/09) that you suggested, it worked as expected with the WIRED switch, but the wireless (burp machine) remote  would take only one picture  but then  no further action.
Before the button push  DIG is displayed on the left and when the remote button push happens USB is displayed and focussing happens and a picture is taken  but then no response to a further push (I waited several seconds) other than the USB text flashed once in response, but  that is all.
The camera does not freeze in that the display view moves in real time but I have to switch off.

The earlier DISKBOOT.BIN version ((185,340 kB 29/07/09)   where the blue LED holds for 10 seconds is quite workable for me so I am not too distressed, but I though I should report results.

Edit: I also note that when rumnning the DISKBOOT.BIN version ((185,340 kB 29/07/09) if the flash fires the picture is recorded the ten second blue Led completes and the flash fires again but no photo is taken

[Microfunguy]

Before the button push  DIG is displayed on the left

Correct.

 

when the remote button push happens USB is displayed and focussing happens and a picture is taken

Correct.

 

then no response to a further push

You are locked-out for two seconds after the first pulse ends.
Try again and press the switch after three or four seconds (depending on how long your switch pulse is).
In latest version you can set the lock-out time from a menu item.

the flash fires

probably the preflash to determine white balance, exposure or whatever.

the flash fires again but no photo is taken

In Stereo menu set camera position to 'R' (for 'right' camera).
If synch is enable and a letter 'F' is displayed at the top you should be able to take a flash photo.

Is 'F' displayed ?

If not, tell me your Canon shooting-mode settings.

[Seagull]

You are locked-out for two seconds after the first pulse ends.
Try again and press the switch after three or four seconds (depending on how long your switch pulse is).
In latest version you can set the lock-out time from a menu item.

Even after 20 seconds there is no response to a buttomn press on the remote.

In Stereo menu set camera position to 'R' (for 'right' camera).
If synch is enable and a letter 'F' is displayed at the top you should be able to take a flash photo.

Is 'F' displayed ?

In the above scenario I do not see an F, but do I see a flash Symbol (the lightning strike) and a remote button press  has the flash fire and  the picture is taken. but then the previously reported hang up occurs. The screen just displays the last picture just taken until the USB cable is removed or I power down the camera.

I do note that a second "DIG" is displayed immediately below the first along with the previously mentioned flick of the USB text, when the second button push is made. The nthere remain the two DIG one above the other.

Sorry I am still in ignorance of what all the different settings mean so I am blundering around a bit but I used "Reset to defaults" and then tried your suggestion above.
 

[whoever]

Even after 20 seconds there is no response to a buttomn press on the remote.

From what you describe it seems that the triac in your optoisolator, once optically opened, gets sufficient current to stay open (you surely checked the output with a voltmeter?)

P.S. It is highly unlikely that Microfunguy's software will be able to mend your hardware...

[Microfunguy]

Let us take this step-by-step  ...

Connect camera to PC using the USB cable.

A photo will be taken.

After the two second time-out another photo will be take .. forever.


Does that work ?

[Microfunguy]

the triac in your optoisolator, once optically opened, gets sufficient current to stay open

Someone using a DIY triac-based flash-trigger mentioned a similar problem to me when using it with studio flash.

The flash had to be turned-off before the trigger would work again.

Any suggestions for modifying the trigger circuitry to avoid this problem  ?

[whoever]

the triac in your optoisolator, once optically opened, gets sufficient current to stay open

Someone using a DIY triac-based flash-trigger mentioned a similar problem to me when using it with studio flash.
The flash had to be turned-off before the trigger would work again.
Any suggestions for modifying the trigger circuitry to avoid this problem  ?

For the flash trigger project, I'd put a capacitor shunted with a resistor, say 0.5 uF and 100k, in series with the triac/thyristor.

For the original project in question, I'd through out the optoisolator and look for a suitable logical level in the circuit. Here is schematics for an excellent Chinese $10- doorbell. Inspired by the discussion, I just got one of those for myself.

[Microfunguy]

For the flash trigger project, I'd put a capacitor shunted with a resistor, say 0.5 uF and 100k, in series with the triac/thyristor.

So, you would need a 400V 0.47uF capacitor ?

schematics for an excellent Chinese $10- doorbell

Good link !

[whoever]

You mean those old-fashioned flashes with 400V on the hotshoe? Oh my... You then need a megaohm-ish resistor, and you may want to adjust the capacitor so that the dead time is not too long... And yes, I believe it has to be rated for that voltage.

[Seagull]

whoever said:

From what you describe it seems that the triac in your optoisolator, once optically opened, gets sufficient current to stay open (you surely checked the output with a voltmeter?)

Yes I had, 4 to 4.5 V for a second or so and then drops .01 or .02 (not a very fancy DMM though).

Microfunguy said:

Let us take this step-by-step  ...

Connect camera to PC using the USB cable.

A photo will be taken.

After the two second time-out another photo will be take .. forever.


Does that work ?

I just tried that and no. The 1st photo is taken (only sometimes, maybe one in three attempts) and then nothing further?

I tried on both front and rear USB outlets on the PC.  The camera batteries were down so Itried afresh set but same intermittent result.

I have a wired  4.5V remote swithch and that works fine.  A photo for each press. After the delay that is.

Maybe I go and buy a wireless doorbell

[Microfunguy]

only sometimes, maybe one in three attempts

That is almost impossible.

Are you in FAST mode ?

While the USB cable is connected is 'USB' displayed ?

[Microfunguy]

OK, that was misleading.
You have to remove the USB cable after the photo is taken and re-insert it a few seconds later.

Does that work ?