Thanks for your thoughts. I would like to clarify the how the 2 sensors will control those 4 cameras with a simple scenario:

Say I want to capture a brown bear. Bears tend to follow the same routes, and so it is easy to set up a photo-trap and take some pictures. I would use 2 laser beams, set up so that they both cross the route of the bear.

On the control unit I would select a sequencial function A->B with a 1 second offset, which means that in case the laser beam A was broken and 1 second later laser beam B was also broken, the control unit will trigger the cameras. This way I can make sure that the bear is aproaching and not departing when trigger goes off.

I will use up to 4 cameras, to capture the scene from different view points. So all cameras are triggered whenever the trigger criteria is fulfilled, but the I will be able to set individual delays and trigger patterns (for instance: continous shooting at the camera's rate, single shot or say 7 shots with a 500 milisec period...).

The reason behind the 2 input 4 output architecture is simple. We need 4 plugs for the 2 sensors, as the lasers will need transmitter and receiver components. There are 4 outputs, simply for allowing the photographer to use multiple cameras for multiple viewpoints. This way we would have 4 input and 4 output plugs.

The XLR plugs I intend to use are faily big, but perfectly suitable for the task. The device would be something wich can be handheld, at least 12cm wide, so that the sensor plugs fit on the top side and the actuator plugs on the bottom side of the device.

We are still in the design phase and that's why we wanted to have some input what kind of features should we integrate into this device and to make some market research too

Thanks once more, if anybody else has something to say, I am very interested.