Replace mic used as trigger with air flow sensor

I need a recommendation on what type of trigger/sensor I need to replace the current trigger which is simply a mic. The impetus for the trigger is a fireplace bellow that forces air down 1/2" Tygon tubing which is connected to to the mic which is integrated in to a circuit board which in turn triggers several different relays. Anyhow, the mic does not work essentially because any sound turns the switches on and off. I need an air flow switch that would only work when air is blown into the tube directly. I considered piezo switch, but think that the induction from all the surrounding sound would also trigger the piezo switch.

Any advice is much appreciated.

Thanks in advance,


A low-scale pressure sensor such as a MPXV7002GP might be of use, to detect the slight increase in internal air pressure that results; a simple comparator circuit to set a detection threshold and create a contact-closure output might be helpful if analog input capability is not available.

Thanks Rick for the quick response.