Re: 555 camera trigger question

On Thu, 3 Jan 2008 13:43:37 -0500, "Jim" <jbasi@xxxxxxx> wrote:

I have been using a digital still camera to take time-lapse photos....one
photo every 60 seconds. I built a timer using a 555 which uses pin 3 (out)
to activate a small 5 volt relay with a diode across the coil. The camera
originally ran on 4 AA cells, but a 6v gell cell now powers the works.

This camera is triggered via a simple pushbutton switch which I soldered
wires onto that go to the relay. (the camera does not go to sleep in this
short of time)

Appearently this all draws more current than I would think 'cause my gell
cell barely lasts 6 or 7 hours before running out of voltage and the camera
shuts down.

So in an effort to reduce total current draw, the 555 is being replaced with
a 7555, and in the same vain, I now think I should be replacing the relay
with an optocoupler of some kind.

The 7555 easily lights an LED (for the 0.5 second or so trigger time), but I
am not up on all the different opto's enough to know what to pick to act
like a button push to my camera.

I would like a suggestion or 2 on where to start here, even some part
numbers if someone has already done this.

Thanks
Jim



Thoughts..
A)
Stay with relay. Use minimal ON time wave.
Purchase very low draw relay. (Telecom relay?)
Maybe use CMOS 555 version.
Power it up with an adapter.

B)
Search Digikey, Mouser etc for 4 pin opto.
(Designers generally won't shop for you on this one.. It's too basic.)


D from BC
.

Quantcast