Sip & puff

[schlebb]

I am trying to source some parts to make my buddy a handicap accessible Game controller. he doesnt know I am going to do this so I really cant ask him questions. he stated before his switch has four positions
hard puff
soft puff
hard sip
soft sip

anyone that could lend some expertise I would be deeply appreciative.

Schlebb

 

[RadioRon]

Sensing the puff or sip pressure can be done with a pressure sensor that is reasonably sensitive. I'm wondering what happens at the output of this. Are we talking about switch outputs, and if so, what kind of voltage and current?

Pressure sensors can get expensive, but a quick look at Digikey finds that Freescale makes inexpensive ones, here is an example:
Digi-Key - MPXM2010D-ND (Manufacturer - MPXM2010D)

The circuit to connect this to will include an op amps for gain and comparison to setpoint voltages. Each of those would drive some sort of transistor switch.

 

[Sceadwian]

RadioRon, how would that sensor be able to detect negative pressures? It only responds to positive pressure.

 

[RadioRon]

RadioRon, how would that sensor be able to detect negative pressures? It only responds to positive pressure.

Yes, you are right. I scanned the data sheet and noted it is a differential (2 port) sensor, but did not catch that it only tolerates positive differential pressure, not negative. I'm looking for an alternative now.

 

[RadioRon]

After reviewing many pressure sensors of the type sold by electronic distributors, I conclude that this is, in fact, not the right technology for the device. All of these sensors focus on precision, and all cost a lot. So I think the right way to go is to either investigate the markeplace for pressure switches such as are used in various pneumatic equipment, or invent a simple sensor for this application.

 

[Roff]

You could use two positive-pressure switches side-by side, antiparallel (physically, not electrically).
There are some sip/puff switches available online, if you have some bucks.