Square wave generator using first two clicks as timer

[glmasouza]

Hello

I am very new at eletronics, and I've been willing to design and produce a photography timer (for time lapse photography)
right now I've been studying to do that using an astable oscilator with a 555 timer, and control time with a pair of potentiometers (one for the high-time and another for the low-time)

but that is a kind of crumpy solution, designwise, and I wouldn't be able to get longer times.

so I thought I should do that with a single pushbutton as input. it would work like this: I press it once and, as soon as I release, it starts counting time until the next press. Right after I press it for a second time, it starts counting time again. After I release the pushbutton, it will wait (in a "low" position) the same amount of time between the first release and the second press, and then it will turn on for the same amount of time bewtween the second press and the second release. it would then repeat these times until I turned the circuit off or the batteries drained.

i don't know if I made myself clear so I made a processing sketch to illustrate my idea, in the following link:
**broken link removed**
(requires java)

in the little program, the red line represents the pushbutton input, and the green line represents the desired output.

the question is:
is it possible to do that? if so, what's the easiest way?
I would greatly appreciate if it included only 555 timer chips and simple components :smile:

i could "easily" do it with arduino, but that would be expensive and not so elegant.

 

[Raza]

One of the circuits you require.
**broken link removed**
An other one :
high on solder - Projects - Arduino Intervalometer for Time-lapse Photography 
A simple but nice circuit.
LucidScience - Build the REPEATING CAMERA TIMER - Page 2 of 5

 

[ark5230]

Best approach could be to get custom made timing sequence generator to suit your requirement.
Timing control / changes / variation could be provided suitably. Simple microcontroller based circuit may serve the purpose. attached photograph shows a similar device using thumbwheel switches to control timing.