Momentary break in N/O circuit

I want to add an auto reset function to our digital water tank gauge. This will be done by fitting a sensor to the breather hose. I need to copy the function of the reset button on the display. This requires two presses of the button, first to turn the display on and the second to reset the amount. The second push needs to be held on for 5 seconds. Basically all I need is a N/O water sensor but will need some way of momentarily breaking the closed circuit for around .5 of a second once water is detected, This would then be the same as pressing the button twice. Power going to the sensor is 2.95v dc.
The problem is not the sensor it is the momentary .5 second break in the closed circuit that I need to know how to do. Is there a simple way of doing this?
Please see the attached drawing to hopefully explain all.