Electronic Swithing

[wilfredmike]

I converted a switch that activates when something moves thru an infered beam. Breaking the beam caused the circuit to send 9 Volts to a selenoid. The selonid activated and pressed the button on a camera. I did not like the noise when the selonid fired, so I remove the selonid and rigged the camera with a wire from the switch and replaced the selonid with a reed switch. Now when the beam is broken the circuit sends 9 volts to the reed swithch and the camera fires when the reed switch closes.

I have now replaced the film camera with an older inexpensive digital camera. The camera is slow to fire and the switch must remain closed for about 8 or so seconds. Therefore I now need the switch to remain closed for now approx. 10 seconds to allow a new digital camera time to do its thing. Can anyone offer a circuit that would allow this.

The 9 volt supply to the reed switch is short in duration and I won't be able to modify that part of the device. The long switch closing will have to be done in the part of the circuit after the 9 volt signal.

Anyone have any ideas.

 

[ivancho]

What you need is the famus 555 timer in monostable mode with a capacitor and resistor combination for a 10sec pulse. Check out:

**broken link removed**
Monostable 55 TImer Calculator

**broken link removed**

Hope it helps,

Ivancho